4661 4665.output

* GB785068 (A)

Description: GB785068 (A) ? 1957-10-23

Improvements in or relating to electric measuring and testing apparatus

Description of GB785068 (A)

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COMPLETE SPECIFICATION. Improvements in or relating to Electric Measuring and Testing Apparatus. We, SHELL RESEARCH LIMITED, a British Company, of St. Helen's Court, Great St. Helen's. London, E.C.3, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to electric measuring and testing apparatus of the kind including a capacitance cell having an electrode structure the capacitance of which is measured when part at least of the interelectrode space is filled with an insulating fluid. Such apparatus will be referred to as electric measuring and testing apparatus of the kind specified. Where only part of the interelectrode space is filled, the arrangement of the cell is such that it is a

predetermined part, whereby the conditions can be reproduced on separate occasions with sufficient accuracy. Such apparatus may be employed for the determination of the dielectric constant of a fluid, by comparison of the capacitance when the inter electrode space, or the part thereof, is filled with the fluid under measurement and the capacitance when it is filled with a standard fluid for example air. Alternatively, particularly in testing operations, the variations of the dielectric constant of different samples of a fluid may be measured, without an absolute determination being made. In some cases the cell may be arranged so that the fluid may be passed through in continuous flow, the capacitance being measured continuously or at intervals for the purpose of detecting variations in the dielectric constant of the fluid. One particular application of such apparatus is in the detection of water in a liquid with which it is immiscible, for example oil. Small quantities of water suspended as droplets in oil give rise to appreciable variation in the apparent dielectric constant of the oil, and, where it is required to provide dry oil, measurement of the dielectric constant of the oil in a capacitance cell may therefore be employed to test for the presence of water. Previously capacitance cells have included an insulated metal probe projecting into a space, which is filled with the fluid under test or measurement, the capacitance between the probe and an adjacent plate (often earthed) being measured. Other capacitance cells have been provided with one or more pairs of plates, at least part of the space between which can be filled with the fluid under test or measurement. An objection to these known arrangements is that after a period of operation the measurements may become unreliable owing to the collection of foreign matter on or around the electrodes. Also, should a relatively large quantity of water enter a cell, for example one which is being used under continuous flow conditions for the detection of water in a stream of oil, it is difficult to free the electrodes of the water which tends to adhere to them. Short of dismantling the cell and cleaning it out, it may thus be necessary to put the cell out of action for a considerable time before the water gets washed away. It is an object of the present invention to provide a construction for a capacitance cell, for inclusion in electric measuring and testing apparatus of the kind specified, which cell is not subject to these disadvantages to any great degree. According to the present invention an electrode structure for the capacitance cell of electric measuring and testing apparatus of the kind specified comprises two or more metal plates of substantially the same size and shape mounted parallel to and in alignment with one another for rotation about a common axis normal to their planes,

electrical conductors interconnecting the plates in two sets to form the two electrodes of a condenser, and one or more planer electrically insulating spiders separating adja; cent plates of the two sets, each spider consisting of a central portion and a number of arms projecting outwards from the central portion, the plates being provided with openings at or towards their centres to allow passage of fluid from the openings in the end plates into those parts of the spaces between adjacent plates not filled by the spiders and the arms of the spiders being shaped so that, when the structure is immersed in a fluid and is rotated about said axis, fluid is - drawn - in through the openings in the end plates and is ejected centnfugally from the gaps between the edges of the plates. According to another aspect of the present invention a capacitance cell for electric measuring and testing apparatus of the kind specified includes a fluid tight compartment, means for supplying fluid to and withdrawing fluid from the compartment, and an electrode structure mounted in the compartment on - a rotatable spindle structure extending out of the compartment through a fluid tight bearing, the electrode structure comprising two or more metal plates of substantially the same size and shape mounted on the spindle structure parallel to and in alignment with one another for rotation with -the spindle structure about a common axis normal to their planes, electrical - -conductors interconnecting the plates in two sets to form the two electrodes of a condenser and one or more planar electricady insulating spiders separating adjacent-plates of the two sets, each spider consisting of a central pofflon and a number of arms projecting outwards from the central portion the plates being provided with openings at or towards their centres to allow passage of fluid from the openings in the end plates into those parts of the spaces between adjacent plates not - filled by the spiders and the arms of the spiders being shaped so that, on filling the compartment with fluid and rotating the spindle structure, fluid is drawn in through the openings in the end plates and is ejected centrifugally from the gaps between the edges of the plates, and -the spindle structure incorporating electic connections leading to the exterior of the compartment from the two electrodes. A capacitance cell in accordance with the invention will be used in operation in com bination with means for rotating the spindle structure and means for measuring the capacitance between the electric connections incorporated in the spindle structure. Where three or more plates are provided in the electrode structure, it is of advantage

to connect the two end plates in the same electrode and to earth that electrode, to reduce the effects of external influences on the cell. The spindle structure may comprise a pair of spaced coaxial members, electrically con nected within the cell one to each of the electrodes, and a pair of slip rings spaced from one another along the length of the spindle structure outside the cell each con nected electrically to one of the coaxial members. Brushes or spring contacts are then provided to make continuous contact with the slip rings as the spindle structure is rotated. In a simple embodiment the plates are substantially circular and are mounted for rotation about a common axis passing through their centres. In a simple case only three plates are provided, the centre one forming one electrode and the two end ones the other One electrode, preferably that including the two end plates, may be earthed together with the parts of the spindle struc ture to which it is connected electrically. The spiders may be provided with three or more equal forms, each of which curves outwardly in the same direction from the central portion, the electrode structure being rotated in operation in a direction such that the curvature of the arms assists in centri fugal ejection of fluid. A suitable material for the spiders is polytetrafluoroethylene, but other materials may be used as long as they are suitable having regard to the pro jected application of the cell. A capacitance cell in accordance with the present invention will now be described by way If example with reference to the drawAng accompanying the Provisional Specifica tion in which: Figure 1 shows a cross section of the electrode and spindle structures of the cell in a plane containing their axis of rotation;

and Figure 2 shows a plan view of a spider; and Figure 3 shows an exploded perspective view of the electrode structure. As shown in the drawings, the capacitance cell includes an electrode structure consist ing of three circular stainless steel plates 1, 2 and 3, and a pair of insulating spiders A and 5 of- polytetrafiuoroathylene, a plan view of one of which is shown in Figure 2. The centre parts of the two outer plates 1 and 3 are cut away leaving a circular opening of radius greater than the radius of the centre portions of the spiders 4 and 5. The spiders 4 and 5 are provided with a central hole 6 and the centre plate 2 is provided with a central hole 7, which enable them to be passed together on to the threaded end part of a metal spindle 8, and secured in position by a nut 9.. The centre plate 2 is provided with a further six holes 10 spaced round the hole 7 at a radius greater than the radius of the centre portions of the spiders 4 and 5. The outer plates 1 and 3 are secured in position by three qually spaced bolts 11 (only one of which is visible in Figure 1), which pass through holes 12 in the plates 1 and 3 and the spiders 4 and 5, and through larger holes 13 in the plate 2, being insulated from the latter by polytetrafluoroethylene washers 14 which fit into the holes 13.. The bolts 11 are secured to an end flange 15 on the spindle structure by nuts 1d, the plate 1 being held away from the flange 15 by spacers 17. The spindle structure on which the electrode structure is mounted, consists essentially of the central spindle 8, -and a metal sleeve 18 coaxial with it, -on the end of which the flange 15 is formed. The spindle 8 and the sleeve 18 are insulated from one another by p olytetrafluoroethylene washers 19 and 20. At an intermediate -point along its length, the spindle structure passes through a fuid tight gland in The .wall of the capacitance cell (not shown) of which it forms part, thekele.ctrode structure thus being mounted within the cell. At the end remote from the electrode structure and outside the capacitance cell, the spindle 8 terminates and has.a slip ring 21 secured to it by a screw 22. The slip ring 21 is insulated from.the sleeve 18 by a polytetrafluoroethylene sleeve 23, and the sc=v .22 is similarly insulated -by a washer 24. A spindle 25 projects coaxially from the end of the sleeve 18 remote from the electrode structure, and a further slip ring 26 is secured to

the spindle 25 by a grub screw 27. An electric motor (not shown) is employed to rotate the spindle 25 in operation, and brushes are provided to make contact with the external surfaces of the slip rings 21 and 26. The lead from the brush contacting the slip ring 21 is connected to the centrerconductor of a short length of coaxial cable, and the lead from the brush contact ing the slip ring 26 is connected to the outer conductor. The other end of the length -of -cable is connected to capacitance measuring apparatus for example some form of Schering bridge apparatus. It will be appreciated from the above description, that the plate 2 together with the spindle 8, the screw 22 and the slip ring 21 are electrically connected to one another but are insulated from the plates 1 and 3, the flange 15, the sleeve 18, the spindle 25 and the slip ring 26, which are all electrically connected, and will usually though not necessarily be earthed. The plate 2 thus forms one electrode of a condenser and the plates 1 and 3 tqgether the other electrode, the spindle structure Providing electrical connections from the electrodes to the exterior of the cell in which they are enclosed. V"hen the canadtance cell is filled with liquid, the spaces lying between the arms of the -spiders 4 and 5 and the major surfaces of the plates 1, 2 and 3 are filled with. liquid, and if the electrode structure is then rotated by means -of the electric motor, liquid is drawn in through the central openings in the plates 1 and 3 and ejected by centrifugaA action from the gaps between the edges of the plates 1-3, lying between the ends of the anns of the spid- rs 4 and 5. The holes 10 in the plate 2 are provided to permit communication between The spaces on. either side of the plate 2 should there he any asymmetry in the flow conditions in the cell. The arms of the spiders .4 and 5. are curved to assist in this action, when the direction of rotation is clockwise, with respect to the spider gas shown in Figure 2. If an absolute - deterutination of the dielectric constant of a liquid or gas is required, separate measurements of the capacitance of the cell are made with two fluids of known dielectric .-constant filling the spaces. in the electrode structure, before it is -measured with the liquid or gas filing those spaces. The dielectric constants of the two fluids being known, that of the liquid or gas can be determined from the latter measurement. The calibrating measurements need of course only be -performed initially, and nqssi131y at iut-eryaJs asacheck, provided that the es.ults are yecor,ded. Where, for example, it is desired -to check a continuous stream of liquid for;impurities, for example oil for the presence of emulsifled water, pan of the -stream is passed through the cell which is provided

with a suitable inlet and outlet for continuous flow, and the capacitance -is recorded continuously or at intervals. Any ,v.ariation in the capacitance will then be due to the presence of impurities or of a change in the -properties of the oil. Due to the rotation of the electrode structure and the consequent flow of liquid through it, the retention of impurities in the inter-electrode space is unlikely. In addition, owing to the self-cleansing action, the -spacing between the plates may be made small without rendering the appara .tus liable to he put out of action by the retention of impurities. This means that for a given plate size the capacitance can be increased and with it the change of capacitance for a given change in dielectric constant, thus reducing the effects of stray capacitance in the leads, etc. and between the plate 2 and the walls of the capacitance cell. (This latter stray capacitance will vary with the dielectric constant of the fluid filling the cell). Further the electrode structure may be modified to increase the capacitance by adding further plates. For example, five plates could be employed, the two outer ones and the centre one being connected to form one electrode and the other two being connected to form the other electrode. Alternatively, only two plates could be employed although the electrical screening provided by having an earthed plate at either end is thought to be advantageous. Whilst polytetrafluoroethylene has been specified as the material for the insulating parts such as the spiders 4 and 5, other materials may be used as long as they are suitable having regard to the intended use of the cell. If the cell is used for the specific purpose of measuring the water content of an oil, such for example as a fuel oil, it may be found convenient to incorporate a reference capacitance cell in the capacitance measuring apparatus, which cell is filled with dry oil from the same source as the possibly wet oil passed through the measuring cell, in order to be able to correct for variation in the dielectric constant of different base oils from which the fuel is derived. The ratio of the capacitances of the reference cell and the measuring cell, may be measured directly by means of a bridge circuit for example. What we claim is: 1. An electrode structure for the capacitance cell of electric measuring and testing apparatus of the kind specified comprising two or more metal plates of substantially the same size and shape mounted parallel to and in alignment with one another for rotation about a common axis normal to their planes, electrical~ conductors interconnecting the plates in two sets to form the two electrodes of a condenser, and one or more planar electrically insulating spiders

separating adjacent plates of the two sets, each spider consisting of a central portion and a number of arms projecting outwards from the central portion, the plates being provided with openings at or towards their centres to allow passage of fluid from the openings in the end plates into those parts of the spaces between adjacent plates not filled by the spiders and the arms of the spiders being shaped so that, -when the structure is immersed in a fluid and is rotated about said axis, fluid is drawn in through the openings in the end plates and is ejected centrifugally from the gaps between the edges of the plates. 2 An electrode structure according to Claim 1, in which there are three or more plates, the two end ones of which are connected in the same electrode. 3. An electrode structure according to either Claim 1 or Claim 2 in which the plates are substantially circular and are mounted for rotation about a common axis through their centres. 4. An electrode structure according to any one of Claims 1-3 in which the spiders have three or more equal arms, each of which curves outwardly in the same direction from the central portion. 5. An electrode structure according to any one of Claims 1A in which the spiders are constructed of polytetrafiuoroethylene. 6. An electrode structure for the capacitance cell of electric measuring and testing apparatus of the kind specified, substantially as hereinbefore described with reference to the drawing accompanying the Provisional Specification. 7. A, capacitance cell for electrio measuring and testing apparatus of the kind specified including a fluid tight compartment, means for supplying fluid to and withdrawing fluid from the compartment, and an electrode structure as claimed in any one of Claims 1-6 mounted in the compartment on a rotatable spindle structure extending out of the compartment through a fluid tight bearing, the spindle structure incorporating electric connections leading to the exterior of the compartment from the two electrodes. 8. A capacitance cell according to Claim 7 in which the spindle structure comprises a pair of spaced coaxial members, electrically connected within the cell one to each of the electrodes, and a pair of slip rings spaced from one another along the length of the spindle structure outside the cell each connected electrically to one of the coaxial members. 9. A capacitance cell according to either

Claim 7 or Claim 8 in which the two end plates are connected in the same electrode. 10. A capacitance cell according to Claim 9 in which said electrode is earthed by connection to the main casing of the cell. 11. A capacitance cell for electric measuring and testing apparatus of the liquid specified, substantially as hereinbefore described with reference to the drawing accompanying the Provisional Specification. 12. In combination, a capacitance cell according to any one of Claims 7-11 and means for continuously rotating the spindle. structure.

* GB785069 (A)

Description: GB785069 (A) ? 1957-10-23

New heterocyclic compounds

Description of GB785069 (A) Translate this text into Tooltip



X Am E 1 \\i; 2- _ PATENT SPECIFICATION e N W 1 ot ^ T' x"v Inventor: MERVYN EVAN 'lit L Date of filing Complete Specification: May 4, 195 i Application Date: May 18, 1955 N Complete Specification Published: Oct 23, 1957. Index at acceptance:-Class 2 (-3), C 2 D 27, C 3 C 5 (A 4: B: C 7: E 5).

International Classification:-C 07 d. COMPLETE SPECIFICATION New Heterocyclic Compounds We, ALLEN & HAN Bu RYS LIMITED, a British Company, of Three Colts Lane, Betrbnal Green, London, E 2, do hereby declare the nvention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to new heterocycliccompounds. The new heterocyclic compoundcs of the present invention are 5-(isobutyl)-5-ethyl-lmethyl thiobarbituric acid and its therapeutically useful salts, particularly the sodium salt The term "therapeutically useful salts" as used herein meanis the: sodium, calcium or lithium salts. The present invention also includes a process for the preparation of the new compounds wherein an isobutyl-ethyl-malonic acid dialkyl ester is reacted with N-methyl-thiourea in a solution of an alkali metal alkoxide, preferably sodium alkoxide, in a lower aliphatic alcohol. The present invention also includes a process for the preparation of the novel Icompounds of the present invention wherein a lower alkyl ester of isobutyl-ethyl-cyanoacetic 6 ( 30 ff J S. o 14369/55. acid is condensed with N-methyl thiourea, followed by hydrolysis The term "lower alkyl" as used herein means an alkyl group containing not more than four carbon atoms. The thiobarbituric acid may be converted into its therapeutically useful salts by reaction with a metal alkoxide in solution in the corresponding alcohol or with an aqueous alkali. The compounds of the present invention are surgical anaesthetics having a significantly shorter duration of action than that of the known, coalpounds, this= making them useful in cases where brief surgical anaesthesia is needed for minor surgical procedures. The activity of these compounds was determined by intravenous administration to mice which were placed on a rotating drum for three minutes after administration Potency (ED 50) is expressed as the dose causing 50 % of the animals to fall off The results are given in Table I below, in, which a lcomparison is made with the known substances Thiopentone Sodium Recovery was determined by periodically replacing fallen mice on the rotating druim TABLE I No of ED 50 in mg per kg -4Compound animals standard error Sodium salt of 5-(isobutyl)-5-ethyl1 l-methyl thiobarbituric acid 140 7 3 0 3 Thiopentone Sodium 116 7 0 0 7 lPrice 3 s 6 d 1 r 61 9 1 Iv__) Similar tests on rabbits in which loss of hypnosis are given in Table II. the righting reflex was taken as a lcriterion of TABLE II No of ED 50 in mg per kg 4Compound animals standard error Sodium salt

of 5-(iso butyl)-5-ethyl-l-methyl thiobarbituric acid 32 2 8 0 3 Thiopentone Sodium 24 2 6 4 0 5 In mice at high equipotentf doses the dura the ED 50 the duration of action is one-half o 10 tion of activity of the sodium salt of of that of Thiopentone Sodium, The median 5-(isobutyl)-5-ethy I-l-methyl thiobarbituric lethal dose of 5-(isobutyl)-5-ethyl-l-methyl acid is one-sixth of that given-by Thiopentone thiobarbituric acid was determined in mice, Sodium, and in rabbits at doses of ten times Table HI, -and rabbits, Table IV. : Ta LE I Compound No of animals LD 50 in mg per kg 4standard error Sodium salt of 5-;(iso: butyl)-5-ethyl-l-methyl thiobarbituric acid 90 74 5 i 1 4 Thiopent 6 ne Sodium 50 79 O 4 4 0 l TABLE IV: -'' ' -No of LD 50 in mg per kg -: C Compound animals standard error Sodium salt of 5 (iso butyl)-5-ethyl 4 l-methyl thiobarbituric acid 23 28 8 i 2; 4 Thiopentone Sodium 14 26 0 0 6 The conpounds:of the-present invention of sodium dried ethyl alcohol, and 62 gm of have also been administered to cats to ascer isobutyl-ethyl-malonic acid diethyl ester was 35 tain whether any undesirable side effects added to this solution followed by 25 gn L of accompanied their anaesthetic properties In N-methyl thiourea The mixture was heated these experiments no cardiac arhyfimnia was under reflux for 24 hours, allowed to cool revealed and there was no -essential difference and poured on to 100 gmn of solid carbon between these compounds and Tfiiopentone dioxide After 20 minutes 400 ml of water 40 Sodium on blood pressure or transmission id was added to the mixture and the oil which an autonomic ganglionm In rabbits there was separated was extracted into ether The no essential difference in their effects on ethereal solution was washed, with water, thern respiration or blood pressure with three succicessive portions of 100 ml of The following examples illustrate the in 2 % aqueous sodium bicarbonate solution and 45 vention: finally with waterThe solution was then dried EXAMPLE 1 over anhydrous magnesium sulphate and Preparation of 5-(isobutyl)-5-ethyl-1-methyl filtered and the solvent ether removed by disthiobarbituric acid tillationThe residue was distilled under 5.3 Gm of sodium was dissolved in 100 ml reduced pressure and the fraction which dis 50 785,069 z 1 - 8,6 tilled at 136-1380 C at 0 7 mm collected; this consisted of 5-(isobutyl)-5-ethyl-1-methyl thiobarbituric acid, which was a very pale green viscous fluid n D 22 1 5592. Calculated: C 54 52 %; -H 7 4 A?/o; N 11 57 %; S 13 23 %. Found: C 54 65 %; H 7 51 %; N 11 71 %; S 13 05 %. EXAMPLE 2. Preparation of the sodium salt of 5-(isobutyl)5-ethyl-l-methyl thiobarbituric acid.

Ml of a solution of sodium ethoxide prepared by dissolving 2 3 gin of sodium in anhydrous ethyl alcohol sufficient to produce 100 ml of solution was added to 2 43 gin of 5-(isobutyl)-5-ethyl-1-methyl thiobarbituric acid, prepared as described in Example 1 The solvent was removed by evaporation and the residual solid crushed into a cream coloured powder, melting point 264-266 C EXAMPLE 3. Preparation of 5-(isobutyl)-5-ethyl-1-methyl thiobarbituric acid. 345 Gm of isobutyl-ethyl-cyanoacetic acid ethyl ester and 157 6 gin, of N-methyl thiourea were added to a solution prepared by dissolving 40 27 ginm of sodium in 600 mil of sodium dried ethyl alcohol The mixture was boiled under reflux for 16 hours, allowed to cool and poured into 3 litres of iced water A mixture of 100 ml of concentrated hydrochloric acid and 200 ml of water was added slowly with stirring and acidification then completed by passing a stream of carbon dioxide through the reaction mixture An oil separated and after this had solidified the solid was removed by filtration and dissolved in 400 ml of' 95 % ethanol 100 ML of water was added to this solution,> a crystalline solid separated on cooling and was removed by filtration and crystallised from 80 % ethanol. The product, 5-(isobutyl)-5-ethyl-1-methyl-4imino thiobarbituric acid was a white crystalline solid, melting point 104 5 to 105 5 O C. To 142 gmin of this compound a solution of 54 ml of concentrated hydrochloric acid in 1,000 ml of water was added and the mixture boiled for 1 hour under reflux and stirred continuously The mixture was then allowed to cool and the organic layer which separated was extracted with ether The ether solution was washed with water and dried over anhydrous magnesium sulphate After filtration the ether was removed from the filtrate by evaporation The residue was distilled under reduced pressure and the fraction which distilled at 141 C at 1 mm was collected 5(Isobutyl)-5-ethyl-1-methyl thiobarbituric acid was obtained as a very pale green viscous liquid nf 2 l 1 5592. EXAMPLE 4. Preparation of the sodium salt of 5-(isobutyl)5-ethyl-l-methyl thiobarbituric acid. 86.48 Ml of a 2 673 N solution of sodium ethoxide in sodium dried alcohol was added to a solution of 56 gin of 5-(isobutyl)-5-ethyl1-methyl thiobarbituric acid in 200 ml of dry benzene The resulting solution was filtered and the solvent mixture removed by distillation under reduced pressure until the reaction 70 mixture became turbid A further 100 ml of dry benzene was then added and the crystals which formed were filtered off and dried in vacuo The product was a cream coloured crystalline solid, melting point 258 C 75 The term "lower aliphatic alcohol" as used herein means an aliphatic alcohol containing not more than 3 carbon: atoms.

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* GB785070 (A)

Description: GB785070 (A) ? 1957-10-23

Improved adherent self-curing polysulphide polymer compositions

Description of GB785070 (A) Translate this text into Tooltip



COMPLETE SPECIFICATION Improved Adherent SelfwCuring Polysulphide Polymcr Compositions. We, MINNESQTA MINING and-MANUFAC- TURING COMPANY of 900 Fauquier Avenue, Saint Paul 6, Minnesota, United States of America, a Corporation organised under the laws of the State of Delaware, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be partictilarly described in and by the following statement :- This invention relates to polysulphide polymer compositions capable of forming highly adherent tough and flexible protective coatings on metal and other surfaces. The compositions are usually applied in

liquid form. and are then permitted to cure at room or elevated. temperatures. The resultant coatings are found to adhere firmly to the metal. They are strong, tough and flexible, and remain so on prolonge exposure to oils, organic solvents, and salt water, and over a wide range of temperatures. The products are therefore useful as protective coatings, sealing and caulking compounds, adhesive bonding agents, and for other pur -poses. The invention is particularly important in its application to liquid polysulphide polymers of the general type described in United States patent No. 2,466,963 having. a molecular weight of about 500 to 12,000 and existing at 25 C. as a liquid. Such polymers may be cured to the rubbery solid state by means of curing agents such as peroxides. The. cured product is flexible and resilient, highly resistant to solvents, oils and brines, and stable on heating ; but it is substantially non-adherent to metal and other surfaces with which the polymer is in contact during the curing operation. Some degree of adhesion has heretofore been imparted to these polysulphide polymers by adding various resins, but the cured products of such compositi'qns have shown inferior properties with respect to solvent resistance and heat resistance. In further describing the. high degree of permanent adhesion now made available by means of the compositions of the present invention, referenceE is here made to the"peel-back adhesion test." Test specimens are prepared by first spread ing a 1/8 inch layer of the composition over the clean surface of a l-by 6 inch strip of aluminium plate, permitting the layer to cure to a firm state, adhering a wire. screen strip to the thus cured composition with afurther-coat- ingof the uncured material, and then curing the entire panel for one week at 80 F. The wire screen strip is loosened at one-end, the assembly is placed in a suitable testing machine, and thestripis peeled back from the surface of the panel at a rate of two inches per minute and at an angle of between 90 and 180 degrees with its initial position'on the panel. The adhesion of the composition to the panel is determined in pounds of removal effort per inch width of the specimen. The compositions of the present invention have provided adhesion test values of well over 60 and even up to 100 pounds or more per inch of width, both as initially prepared and also after the test strips have been held in warm oil, solvents or brine for a number-of days. In a number of cases-the-test has been limited by the failure of the metal-screen at stresses of about 80 to 100-pounds per inch width. On the contrary, previously available adhesive compositions based on the said polysulphide polymers have in general provided much lower

initial adhesion values, and these values have decreased greatly when the samples were subjected to the test conditions described. The polymers by themselves, i. e. when cured in the absence of conventional resinous or other tackifier additives, have produced zero adhesion values under some or all of these test conditions. It is therefore a principal object of this invention to provide self-curing polysulphide polymer compositions, which when cured in contact with metal or other surfaces form strong, adherent, and permanent bonds thereto, the cured polymer being tough and flexible, and highly resistant to oils and aromatic fueXs, over a wide range of temperatures. Another object, is to provide spreadable polymeric polysulphide compositions which polymerise rapidly to form adherent, heat-resistant and solvent-resistant coatings. A further object is the provision of coated surfaces or articles hav-- ing an adherent coating or component of tough and flexible, heat-resistant, and solvent-resistant, cured polysulphide polymer material. These advantages are obtained, in accordance with the invention, by a composition comprising a liquid aliphatic saturated low molecular weight polysulphide-polymer, lead peroxide in an amount sufficient to cure said polymer, and small but significant amounts of an active furane derivative and an. organic acidic component. A specific example of-a commercially availahle liquid aliphatic saturated low molecular weight polysulphide polymer that has been found eminently suitable for the purposes of this invention is a-material known as "Thiokol" (Registered Trade Mark) LP-2 polymer. The said LP-2 polymer is a liquid aliphatic saturated oxahydrocarbon polysulphide polymer having a molecular weight-of about 4000 and having reactive mercaptan groups capable of further polymerization and cross-linkage. It is obtained by the condensation polymerization of a mixture of 98 mol percent of dichloroethyl formal and 2 mol percent of trichloropropane with sodium polysulphide, followed by reductive cleavage of disulphide groups to yield a product having an average molecular weight of about 4000 and, by calculation, an average of about two and one-half mercaptan (-SH) groups per molecule. Its viscosity is 450 poise, specific gravity 1.27 and pH 6 to 8. Another suitable commercially available liquid polysulphide polymer is"Thiokol" LP-3. These polymers or polycondensates are fully identified in an article by J. S. Jorszak and E. M. Fettes, appearing in the February 1951 issue of Industrial and Engineering Chemistry. "Thiokol"LP-32 is another suitable polycondensate which has about the same viscosity as the LP-2. The. formulation of the LP-32 has been

stated to contain only 0.25 percent of the trifunctional component, e. g., trichloropropane, whereas the LP-2 requires about 2 percent of such component in its formulation. In the following illustrative examples,. proportions of components will be indicated in parts by weight unless otherwise stated. Example I Parts LP-2 polymer....................... 100 Carbon black 30 Furfuryl alcohol 3 Lead peroxide........................... 8 Stearic acid.......................... 1 Toluene.................................6 The lead peroxide, stearic acid and toluene were separately combined into a heavy paste which was mixed into the mixture bf the poly mer, carbon black and furfuryl alcohol just before application. The adhesion to aluminium in the peelback adhesion test was found to be 40 pounds per inch, whereas a. similar composition containing no furfuryl alcohol exhibited no adhesion. After initial mixing, the com position could be satisfactorily : applied and spread during a period of about 22 houris. A softer cured product results when the carbon black reinforcing pigment is omitted. Example II Parts LP-2 polymer........................... 100 Carbon black........................ 35 Furfuryl alcohol........................ 3 Lead peroxide.......................... 7 p-Dioxane..............................3 Maleic acid (or anhydride)............ 0.14 Compounding was carried out as in Example I and peelback adhesion values were deter mined. Values of over 100 pounds per inch were consistently obtained. A similar composition. containing no fur furyl alcohol showed good adhesion to the aluminium when first tested, but this adhesion was completely lost on immersion of the specimen for several days in an aqueous medium such as 3 % salt solution or sea water,

whereas the composition containing the fur furyl alcohol remained firmly bonded under such conditions. Example III Parts LP-32 Polymer.................... 100 Alumina (powdered) 50 Furfuraldehyde.....................4 Sulphur......................... 0.1 Lead peroxide....................... 8 Stearic acid....................... 1 Toluene.............................. 6 The polymer employed in this example has a lesser degree of cross-linking than that of Examples I and II, and hence a small propor tion of sulphur is added to provide a better cured product. This composition develops fully effective adhesion to aluminium and in a some what shorter time than those of the-previous examples. The adhesion is permanent under prolonged immersion in oils, solvents or brine. Example IV Parts LP-3 polymer........................ 100 Furfuryl alcohol............ 4 Lead peroxide 20 Stearic acid 2. 5 Xylene................................. 15 The polymer of this formula has an average molecular weight. of about 1,000, a viscosity at 25 C. of 10 poise and a pH value of 5 to 6. The lower molecular weight polymer requires the use of an increased amount of the lead peroxide curing, agent. The product provides excellent adhesion to aluminium under the various test conditions previously indicated. In the above examples, the mixture of curing agenti-organic acid and solverit is added to a pre-formed blend of the liquid polymer and the furfuryl alcohol or equivalent active furane derivative just prior to application of the adhesive composition. The separate mixtures prior to being mixed together are entirely stable and may be stored for long periods of time without change. Other pre-combinations may be made s. desired, or the separate ingredients may ; simultaneously be mixed together or may be added individually in forniing the spreadable adhesive composition. These

various methods of forming the final composition provide equally satisfactory final results when the mixture is prepared just before application. Where. premixed subcombiiiations are to be stored for long periods of time, it is found desirable to combine the polysulphide polymer, furane derivative and inert additives in one mixture, and the peroxide catalyst and acidic component, together with sufficient inertvolatile liquid vehicle to provide improved. miscibility, in another, as noted in Example I. Thus a mixture of 5.5 parts of lead peroxide, 0.7 parts of stearic acid and 318 parts of furfuryl alcohol is not completely, stable on long standing and will eventually reach a stage at which it will no longer produce an adequate cure of the polymer when mixed therewith. However the individual components in the amounts indicated, or the freshly combine components, may be added to 100 parts of the liquid polymer to produce a highly effective adhesive or coating composition. In the absence of the. stearic acid or equivalent component of the foregoing formula the adhesion obtained is Iess effective ; but initially acid-free mixtures of lead peroxide and furfuryl alcohol gradually improve in this respect with moderate aging. For example, a mixture of 8 parts of lead peroxide and 4 parts of furfuryl alcohol when freshly prepared and blended with a mixture of 100 parts of LP-2 polymer and 30 parts of carbon black provided poor adhesion; but after the peroxidealcohol mixture had aged for one month at 90 F., the peelback adhesion value of the mixture with the polymer and the carbon black was found to be at least about 60 pounds per inch of width. Prolonged aging. of the mixture, however, lessened its utility in the same manner noted in connection with the combination of peroxide, alcohol and stearic acid. Thus, compositions. comprising the polymer and a mixture of lead peroxide and furfuryl alcohol may provide either very poor. or very good adhesion values depending on the length of time-the mixture of peroxide-and alcohol is allowed to age prior to blending with the poly mer. In probable explanation of this phenomenon ; it is-believed that reaction slowly occurs between, the peroxide and the alcohol, with production. of acidic components, during the aging period., The presence of a small but significant pro portion of an acidic component appears to be essential to the development and maintenance of a high adhesion value, it being immaterial whether the acidic component results from a formation thereof in situ or from adding acidic material or both.

Example V Parts LP-2 polymer.......................... 100 Carbon black 30 Furfuraldehyde..................... 3 Leadperoxide................... 8 Stearic Stearicacid.............................1 Xylene.....................................'6 Peelback adhesion values of 60 pounds per inch or more were obtainedwiththis composi tion. High-adhesion values were retained on prolonge soaking of the te5t. > specimens in oil, solvents, and brine ar both room and elevated temperatures. Example VI Parts LP-2 polymer............. 100 Carbon black........................... 30 Liquid furfuralcohol resin ("DUREZ 14371") (made by-coiitrblled acid catalysis of furfuryl alcohol as described in U : S. patent No. 1,665,235)..................... 5 Lead peroxide............... 8 Stearic acid....................... 1 Xylene.................................... 6 The peelback adhesion value obtained with this composition was at least 60 pounds per inch. The amount of active furane derivative required, based on 100 parts of the liquid polymer3 is within the approximate limits of 1 to 6 parts. With less than 1 part of furfuryl alcohol for example, the coating on aluminium loses the-greater part of its adhesion when the assembly is held for several days in 3 % brine. In amounts larger than about 6 parts of fur furyl alcohol, the resulting cured coating is found to soften unduly when subjected to elevated temperatures. Within'this broader range the most effective combination of properties is obtained'at approximately 2 to 4 parts of the'furfuryl alcohol on 100 parts of the liquid LP-2 polymer. The substitution of other

of the liquid-polysulphide polymers and of other active furane derivatives, e. g. fur furaldehyde or furfuryl alcohol resins, may serve to alter these exact-proportions to some extent, although'it is believed that in all cases the best results are obtained within the relative proportions of about 1 to 6 parts of the active furane derivatives and 100 parts of the liquid polymers. The tenm"active furane--derivatives"as here employed derivatives-of furane that are comparatively easily oxidized with the formation of acidic materials, such as fur furyl alcohol, furfuraldehyde, and liquid resins formed by catalytic polymerization of furfuryl alcohol in the-presence of strong a ds. Et exclues derivatives that are difficult to oxidize, such-as tetrahydrofurfuryl alcohol, and furane itself. Example VII Parts LP-2 polymer.... 100 Carbon black..... 30 Lead peroxide.... 8. 5 Stearic acid... 1.07 Maleic. acid........ 0.14 Furfurylalcohol.....................5. 86 The cured coating adhered firmly to aluminium, steel, wood and other smooth surfaces with which the composition was placed in contact prior to curing. The bond was main tained at elevated temperatures and after pro longed contact with oils, brines, and aviation fuels. This coating, like those of the previous Examples, was flexible at low temperatures and provided a combination of properties making it highly useful as a sealant for fuel tanks and oil tanks of airplanes.. As has already been pointed out, composi tions comprising liquid polysulphide polymer and a mixture of lead peroxide and furfuryl alcohol may provide either very poor or very good adhesion values depending on the length of time the mixture of peroxide and alcohol is allowed to age prior to blending with the

polymer. For more accurate control, it is preferred to combine the furfuryl alcohol with the polymer rather than with the peroxide, and to add a small proportion of an acidic material with the latter Stearic and phthalic acids are useful for this purpose. The combination of the liquid polymer, furfuryl alcohol, lead peroxide and stearic or phthalic acid within the approximate. relative proportional limits of 100: 1 to 6: 5 to 20 : If to 5 produces a com position capable of establishing and retaining a high value of adhesion to aluminium as measured by the peel-back test. Maleic, fumaric and furoic acids are still more effective. These acids may be employed in somewhat smaller proportions as indicated in Example II. Rather high preliminary adhesion values have been obtained with com positions. comprising the liquid polymer, lead peroxide, and one of these acids, in the absence of furfuryl alcohol or equivalent ; but such compositions do not retain their adhesive ness when the specimen is subjected to pro longed soaking in brine. With the addition to the formula of a small amount of furfuryl alcohol, permanency of the adhesive bond under such test conditions is provided. The internal strength of these compositions is superior to that obtainable with stearic acid. Oxalic and salicylic acids are also highly effective, and in fact are somewhat superior to maleics fumaric and-furoic. : cids-in imparting notwnly a rather high adhesion value but also an observable increase in permanency f bond under the brine exposure test. However the adhesion value and permanency of bonds made in the presence of these acids are greatly improved by the addition of furfuryl alcohol to such compositions. 'What we claim is :- 1 : A spreadable polymeric composition capable, in the form of a thin coating on a smooth metal surface, of curing at xoom tem-

perature to a permanently firmly adherent state, said composition comprising a liquid aliphatic saturated low molecular weight poly sulphide polymer, lead peroxide in an amount sufficient to cure said polymer, and a small but significant amount of an active furane derivative and of an organic acidic com ponent.


* GB785071 (A)

Description: GB785071 (A) ? 1957-10-23

Improvements relating to wheel suspensions particularly for motor vehicles



FR1131175 (A) US2811214 (A) FR1131175 (A) US2811214 (A) less Translate this text into Tooltip



4, ' 7 C v-s PATENT SPECIFICATION 785071 Date of Application and filing Complete Specification May 24, 1955. No 15003155. Application made in Germany on May 24, 1954. Complete Specification Published Oct 23, 1957. Index at Acceptance:-Class 108 ( 2), D 2 A 2 A. International Classification: -B 62 d. COMPLETE SPECIFICATION Improvements relating to Wheel Suspensions particularly for Motor Vehicles We, DAIMLER-BE Nz AKTIENGESELLSCHAFT, of Stuttgart-Untertiirkheim, Germany a company organised under the laws of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the followmg statement:- This invention relates to a wheel suspension, particularly for a motor vehicle, in which the wheel carrier is arranged on a swinging axle member, and is guided by two longitudinal link members at different levels articulated to the vehicle superstructure or frame (hereinafter included in the term superstructure) Each wheel of a pair is thus guided by the three members independently of the other wheel in a kinematically simple manner, the forces arising at the wheel being transmitted simultaneously to the vehicle superstructure by the link members. The two longitudinal links transmit the forces acting on the wheel in the direction of travel directly to the superstructure without substantially stressing the articulation of the half axle Hinge joints with pins subjected to heavy bending stresses can be avoided All three members can be constructed as simple light rods, especially if the links are arranged to be stressed in tension by the forces ariing on braking. If the two links are directed towards opposite ends of the vehicle, the torque acting on the wheels is taken up in particularly favourable fashion, but the wheel carrier is swung about a transverse axis when the wheel deflects against the springing because the upper link moves through an arc to one side and the lower link through an arc to the, other side. This movement of the links is immaterial with respect to the track position of the wheel as long as the joint connecting the half axle to the superstructure is disposed at the level of the wheel centres, i e of the axes of rotation of the wheels, since the turning of the wheel

carrier due to the links is about a transverse axis coinciding with the axis of the half axle. However, conditions are different if the point of articulation of the half axle is set lower than the wheel centres particularly in 50 order to reduce variation in track on wheel deflection In this case, the axis of the wheel is different from that of the half axle, so that, when the wheel deflects, the wheel axis swings on the surface of a cone due to the turning 55 of the wheel carrier produced by the arcuate movement of the links This swinging causes the wheel to diverge to some extent from the direction of travel. According to the invention, in a wheel 60 suspension having a wheel carrier arranged on a swinging half axle and guided by two longitudinal links articulated to and directed at different levels towards opposite ends of the vehicle superstructure, or directed towards the 65 same end thereof and made of different lengths, the half axle is articulated to the superstructure at a level lower than the axis of the wheel, and both the half axle and the links are so articulated to the superstructure as 70 to be movable in all directions. With this arrangement, a simple but prgctical construction of the suspension is possible and divergence of the wheel from the direction of travel and track variation can be substan 75 tially reduced. A particularly simple and advantageous construction is obtained if the upper link is articulated to the wheel carrier nearer to the wheel centre than is the lower link This arrangement 80 makes it possible to keep the movement of the wheel axis on a conical surface whose axial inclination is determined on the one hand by the joint between the half axle and superstructure and on the other hand, with links of equal 85 length, by the centre point of the wheel carrier which couples the two links, between the respective joints with the links so small that it can be neglected in practice Divergence of the wheel from the direction of travel when it 90 deflects is correspondingly reduced. If desired the articulation points may be so arranged that the track divergence when the wheel deflects upwardly is less than when it 2. 758,071 deflects downwardly, particularly in such a universal joints and may be spherical or rubmanner that when the wheel deflects upward ber joints. ly, that is generally under conditions of heavy If the wheel r and thus the half axle a moves wheel loading, the divergence from the direc up or down, the point C is guided in an arc tion of travel is substantially nil throughout about the straight line A-E and the point D 70 the whole deflection The greater divergence is guided in an arc about the straight line when the wheel deflects downwardly is ima A-F,

as shown by the arcs C-C and D-D' material as regards the road-holding properties for the case of upward movement In other of the vehicle because the wheel is then only words, the triangles A E C and A F D tilt lightly loaded and virtually no disturbing forces about the lines A E and A F respectively The 75 can be produced If the half axles on the two centre point B of the wheel carrier b which sides of the vehicle are articulated on a com acts as a coupling between the two links e and mon axis extending in the longitudinal direc If, then substantially executes a movement tion of the vehicle or are arranged to cross each towards Bl in a perpendicular plane of the other, their length is considerable and this, vehicle, whilst at the same time the said wheel 80 particularly with a low-set -articulation point, carrier swings about a transverse axis into the makes it possible to ensure small variations in position bl Since, however, the wheel pivot wheel camber g coincides with the axis of the half axle a (ie. Reference will now be made to the accorm the prolonged axis of rotation of the wheel -panying drawings, in which: passes through the point A), there is practi 85 Figure 1 is a perspective diagram illustra cally no divergence of the wheel from the ting, for explanation purposes, a wheel sus direction of travel z and the wheel axis or pivot pension with a pendulous half axle articulated g merely moves in the said transverse axis. to the vehicle superstructure approximately at The arrangement of Figure 2 differs from wheel-centre height and oppositely directed that of Figure 1 in that the point A of articu 90 longitudinal links lation of the half axle is displaced downwardly Figure 2 a similar diagram of a suspension from the position (A) at wheel-centre level, in accordance with the invention with a half preferably to approximately the level of the axle articulated to the superstructure below point C or even lower In this case also, the the wheel centre: joints at C and D execute arcuate movements 95 Figure 3 a plan view of the suspension about the axes A-E and A-F when the -according to Figure 2, wheel deflects The -wheel carrier b conseFigure 4 a deflection diagram for the sus quently swings about the axis A B and the pension of Figures 2 and 3, -wheel pivot g executes a movement on the Figure 5 a suspension similar to that of conical surface k with apex angle O At maxi 100 -Figure 2, but with lower-set longitudinal munm spring deflection, the axis or pivot g may, -links for example reach the position g' (Figure 3) Figure 6 a deflection diagram for the sus which corresponds -to a wheel divergence pension of Figure 5, through angle a It should be noted that Figure Figure 7 a side elevation of one practical -3-illustrates an arrangement which is reversed 105 form-of construction, in-mirror-image fashion in comparison with Figure 8 a rear elevation of the suspension -the -arrangement of Figure 2, the

movement of Figure 7, from g to -g' being assumed to be a movement Figure 9 a plan view of the suspension of towards the rear. Figures 7 and 8, -H If the angle a is plotted against the deflec 110 Figure 10 a detail from Figure 7 to a larger -tion h of the wheel centre B, the result will scale and partially-in section, and be approximately as shown in Figure 4 The Figure 11 a perspective diagram of a sus deflection increases progressively, approxipension with a pendulous half axle and two mately= parabolically, with the magnitude of superposed longitudinal links directed -the deflection from the neutral mid-position O 115 -towards the same side If -the total deflection H comprises equal In the wheel suspension of Figure 1, the -upward and downward movement, equal maxiwheel r is carried by a pendulous half axle -mum angles am at both end positions are which is articulated to the vehicle superstruc obtained. ture (or frame) at a point A, at wheel-centre With the suspension of Figure 5, the angle 120 level It is fixed to the wheel carrier b, with is decreased by disposing the wheel axis or which the wheel pivot g is fast, at a point B -pivot g not at the mid-point Bo between the which is midway between C and D and, in the joints C and D, but at B, while the longitu-diagram,-is at the same time the wheel centre dinal links e and f are set lower The wheel Links e and f respectively are articulated to -carrier b then swings about the straight line 125 -the lower end C and the upper end D of the A-B O The resulting half apex angle e/2 is wheel carrier b, the said links being oppositely -smaller than the half apex angle q/2, so that directed longitudinally of the vehicle and con the divergence a is correspondingly smaller -nected to the superstructure at points E and: Figure 6 is a diagram similar to-Figure 4 for F The-articulations A, -C, D, E and -F are all a suspension-substantially -according to Figure 130 795,071 The upward movement of the wheel from the mean position of rest O is + h and the downward movement -h By appropriately proportioning the half axle and links and selecting the position for the mid-point of the wheel and the points of articulation of the links, a very small maximum divergence am, to one side and a '1 to the other side can be obtained on upward wheel deflection If desired oci may be made equal to a ' There is certainly a somewhat greater angle of divergence am ' on downward wheel deflection, but even this can be kept to narrow limits, for example 15 to 20 minutes of -angle, within the limits of accuracy of production and assembly Moreover the somewhat larger angle does no harm as thewheel is unloaded under the conditions in which it occurs The divergence on upward wheel deflection can be limited to 2 to 3 minutes. Figures 7 to 10 show a practical form of construction of the wheel suspension of Figure 2 However, the joints by which the half axles are

articulated to the vehicle superstructure, as shown through an intermediate axle support in the form of an axle-gear housing 11, are displaced to one side of the vertical transverse plane through the wheel centres. In this construction the housing 11 is secured to the frame 10 with the interposition of elastic cushions, for example The pendulous half axles 13 a, 13 b are mounted on a pin 12 arranged longitudinally of the vehicle on the underside of the gearing Wheel carriers 15 carrying the wheels 14 are fixed to the half axles Upper rearwardly directed links 18 and lower forwardly directed links 19 are articulated to the wheel carriers by joints 16 and 17 and to the frame 10 by joints 20 and 21 The wheels are driven from the gearing 11 by articulated shafts 22 and the half axles are sprung by helical springs 23. The pin 12 is carried on the housing of the gearing 11 in eyes 24 and 25 The half axles 13 a and 13 b are mounted on the pin 12 by rubber bushes 26 and 27, if desired with the interposition of sleeves firmly adhering to the bushes On account of the rubber bushes 26, 27, the half axles are free to follow the movements of the links 20 and 21 The joints 16, 17, 20 and 21 may be spherical or pin joints with interposed rubber cushions or sleeves. The suspension of Figure 11 differs from those described above in that the longitudinal links e and f are directed to the same side of the wheel carrier b, so that the axes A-E and A-F about which the articulation points C and D move in arcs are on the same side of the wheel centre B and half axle a The upper link f is made shorter than the lower link e. In this case also the wheel carrier b becomes inclined when the wheel deflects up or down, the inclination being the greater, the lower the point A is located below the level of the wheel centres In this case also, divergence of the wheel pivot can be reduced by lowering the articulation points C and D. The arrangement illustrated in Figures 1-10, in which the lower links e or 19 are 70 directly forwardly and the upper links f or 18 rearwardly, results in the said links being stressed in tension upon braking. As an alternative for the arrangement illustrated in Figures 7-10, in which the two 75 half axles are mounted side by side at the middle of the vehicle, the said half axles may cross each other in per se known manner and be each mounted beyond the middle of the vehicle on the side remote from the respective 80 wheel carrier.

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* GB785072 (A)

Description: GB785072 (A) ? 1957-10-23

Improvements in or relating to the preparation of aromatic carboxylic acids



BE538436 (A) FR1132433 (A) NL92384 (C) US2839575 (A) FR1132434 (A) BE538436 (A) FR1132433 (A) NL92384 (C) US2839575 (A) FR1132434 (A) less Translate this text into Tooltip



PATENT SPECIFICATION 7815072 Date of Application and filing Complete Specification: May 25, 1955. -No 15120/55 Application made in United States of America on May 27, '1954. Complete Specification Published: Oct 23, 1957. Index at Acceptance "-Class 2 ( 3), C 2 B 29, C 3 A 10 A( 4 D: 4 E 5 G 1 5 G 2), C 3 A 16 B( 2 C 5 G 1 5 G 2), C 3 (Al O El: C 2) ' International Classification:-C 07 b, c.

COMPLETE SPECIFICATION ' Improvements in or relating to the Preparation of Aromatic Carboxylic Acids. We, N V DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ, a company organised-under the laws of The Netherlands, of 30 Carel van Bylandtlaan, The Hague, The Netherlands; do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is tobe performed, -to be particularly described in and by the following statement: A - This invention relates to the preparation of aromatic carboxylic acids and is concerned in particular with the preparation of aromatic monocarboxylic acids, and 'also dicarbdxylic acids and their partial esters by the oxidation of alkyl-substituted aromatic hydrocarbons, and alkyl substituted aromatic monocarboxylic acids and their alkyl esters respectively, oxidation being effected in the liquid phase with molecular oxygen or a molecular oxygencontaining gas In recent years the production of aromatic dicarboxylic acids, such as terephthalic acid, has become of particular interest since, for example, terephthalic acid can be esterified by one or more appropriate alcohols, especially glycols, to give esters possessing properties which render their polymers valuable as intermediates in the production of synthetic fibres. Thus, there has been much interest in developing a process for the efficient, low-cost production of these acids and their alkyl esters from cheap, readily available raw materials. The primary raw materials considered hitherto have been hydrocarbons such as the xylenes and other alkyl-substituted benzenes, and the toluic acids In general, the prior processes for converting these hydrocarbons or benzene monocarboxylic acids to the desired 'benzene dicarboxylic acids have involved oxidation, using one or more oxidizing agents to effect the reaction. Employment of molecular oxygen as the oxidizing agent (usually in the presence of-a suitable catalyst) has been effective 'to some extent in producing the desired dicarboxylic lPrice 3 s 6 d l acids, but its use has also introduced problems to which no satisfactory solutions have been found When alkylated aromatic compounds -contain several oxidizable alkyl groups, or when the-alkyl substituent groups contain-relatively 50 longer chains, it is found that whilst the oxidation of the first alkyl group to a carboxyl group takes place with more or less ease, the subsequent oxidation of the resulting alkylated aromatic monocarboxylic acid to the,dicar 55 boxylic acid is more difficult, so that it 'i difficult to obtain the dicarboxylic acids by this method 'According to the present invention there is provided a process for preparing an aromatic 60 carboxylic acid which

comprises oxidising an alkyl-substituted aromatic hydrocarbon 'or an an alkyl-substituted aromatic monocarboxylic acid as hereinafter defined or alkyl ester thereof in the liquid phases with m 6 olecular oxygen or 65 a molecular oxygen-containing gas and in the presence of a saturated aliphatic hydrocarbon which is also oxidised by the said molecular oxygen or molecular oxygen-containing gas wherein the proportion by weight of saturated 70 aliphatic hydrocarbon in the reaction mixture is at least 10 % of the aromatic reactant present therein Preferably the oxidation is effected in a substantially anhydrous'liquid phase system and, if desired, in-the presence of more than 75. one such saturated aliphatic hydrocarbon which is also oxidized Excellent conversion levels are obtained in such a system maintained at low temperatures (preferably 100-200 C) and pressures (preferably 1-5 atmospheres abso 80 lute), a catalyst preferably being present. The amount of the saturated aliphatic hydrocarbon present in the reaction zone is a critical factor in effecting the oxidation of the;aromatic reactant; the oxidation proceeding at a practical 85 rate only when the amount of aliphatic hydrocarbon present in the reaction mixture exceeds about 10 % by weight of the aromatic reactant present therein Higher concentrations of the aliphatic hydrocarbon, up to about 10 times 90 2 ' ', 785,027:: :. the weight of the aromatic reactant, may be desired product e: plo Ve;;without significantly affecting the Where the saturated aliphatic hydrocarbon " conversion level, but it is preferred that the employed is normally gaseous under reaction weight of aliphatic hydrocarbon does not exceed: conditions, the hydrocarbon is dissolved in a about 6 times the weight of aromatic reactant diluent which may be any liquid which is inert 70 Optimum yields and conversions are obtained with respect to the organic reactants and their when the weight ratio of aliphatic hydrocarbon oxidation products, and which-does not inhibit to aromatic reactant lies within the' range'of the desired oxidatiofireaction It-is preferred from about 1: 1 to about 4: 1 that the organic liquid be miscible-with the The-saturated aliphatic hydrocarbon may be aliphatic and aromatic reactants, since the 75 any saturated aliphatic hydrocarbon which is oxidation preferably is carried outin 'a homoreadily susceptible to attack by molecular oxygen geneous reaction system Suitable organic at the temperatures and pressures employed in liquids include aromatic hydrocarbons containthe reaction zone Suitable hydrocarbons in ing no substituent groups which are vulnerable clude, inter alia, the straight-chain alkanes, for to the attack of molecular oxygen under the 80 example ethane, propane, pehtane, hexane, reaction conditions, and other argmatic hydrononane, and decane, and the branched-chain carbons which do not inhibit the

desired oxidaalkanes such as the various isomers of butane, tion reaction, for example benzene, its higherheptane, octane aind decane Mixtures of-such: -alkyl' substitution products, such -as tertbutyl aliphatic hydrocarbons may also be used It is benzene, or its halogen-substitution products, 85 preferred that"the saturated aliphatic hydio such as chlorobenzene and p-dichloro-benzene. carbon be a normal alkane, though the cornm -Naphthalene and naphthalene derivatives are mercially available mixtures of aliphatic hydro excluded,'since these compounds inhibit oxidacarbons such'as' gasoline or other liquid petro tion Also suitable as the diluent are the alileum fractions W hich 'have been freed of phatic carboxylic acids; the lower mono 90 aromatic compounds are also suitable carboxylic acids such as acetic acid and proThe desired oxidation of the aromatic corn pionic acid' being preferred; the methyl and pound occurs, nly when a liquid phase is ethyl esters of such acids; aliphatic ketones, present The liquid phase may comprise the such as di-isobutyl ketone; and aliphatic and aromatic reactant- itself or another organic com aromatic nitriles, such as acetonitrile and 95 pound which 'is a liquid under the reaction benz 6 nitrile. conditi 6 ns The liquid may act either as a Du'ring the oxidation reaction water may be dispersant or as a solvent for the various formed and its removal is desirable to prevent reactants present 'in the reaction mixture, and the formation of two immiscible liquid phases. must be-prese/it in sufficient amount to ensure For this reason the concentration of water 100 that at all times the reaction mixture is in the either as a liquid or as a vapour in the reaction liquid phase, 6 so i'at intimate contact between zone should be maintained at as low a level as the molecular oxygen and the aromatic and possible and preferably the system is mainaliphatic reactants can be maintained It is tained in a substantially anhydrous state. preferred that the 6 rganic liquid employed be Removal of water from the reaction zone may 105 a solvent for both the aromatic and' aiphatic be 'effected by venting the vapours evolved reactants during reaction, condensing the vapours, If thie liqclid employed is a solvent for the separating the condensed water and returning reactants,-the mount of such li 4 uid employed any organic component to 'the system Deshould be sufficient conipltely to dissolve all of hydration may also be 'accomplished by the use 110 the reactants' a d a moderate excess, about of dehydrating agents in the raction zone itself. % to about 100 %, over this amount is pre' If dehydrating agents are employed,'care must ferred If the re'ctants tare substantially in be taken to ensure that such agents are inert soluble in' the liquid, so

0that the liquid acts with respect to all the components of the merely ds' a dispersant, the amount of liquid reaction mixture 115 efiploy 6 d' houild be sufficientbto maintain the The alkyl-substituted aromatic compounds multi-phase systemi in the form'of a dilute, which may be oxidized to mono or dicarboxylic readily fluid uspension of the reactants in the acids by the' process of the present invention liquid ' ' ' ' are the alkyl-substituted aromatic hydrocarbons, 'It has been found that the saturated aliphatic alkyl-substituted aromatic monocarboxylic acids 120. hydrocarbons previously nmeintioned, which are which contain one or more oxidizable alkyl liquid under ieactio''coniditions,;are eminently substituents, and alkyl esters of these acids. satisfactory as' the organic liquid ' Thus, such Alsd included within the terms " alkyl-substialiphatic hydrocarbons'as n-decane, for example, tuted 'aromatic hydrocarbons "' and "alkylmay be emp 16 yedin'the dual role of c 6-reactant substituted aromatic mono-carboxylic acids" 125 and' sbolve't or dispersahnt It is 1 preferable to are those substitution derivatives of the above carry out 'the process 'of the inventioni-in this hydrocarbons' and acids which contain one or way since it has the' advantage of reducing the more other substituents either in the aromatic number of com 1 omiuds present in the'reaction ring or in the' akyl side chamin, which subzone and thus'-implifying the separation of the stituents are not -themselves oxidized and do 130 a temperatures betwveen'aboutf 85 -and about 250 C;, temperatures between about 100 C and about 206 C being preferred, for -at these temperatures a, smooth, effective oxidation of the desired monocarboxylic acid to the corre 70 sponding dicarboxylic acid at high conversion levels with a'minimum of undesirable side reactions may be obtained. The oxidatiopn may be carried out at substantially atmospheric pressure, although in -15 some cases it will be found that the reaction progresses i a more desirable manner under moderate pressure Such pressure need not exceed, bout -7 atmospheres (gauge) and generally a pressure of from about 2 to about 4 80 atmospheres (gauge) will be found quite sufficient to give-the desireddegree of conversion, The process of the present invention is illustrated by the following examples 85 EXAMPLE I Parts by weight of p-xylene were dis-' solved i N 50 parts by weight of n-octane and the mixture was charged to a reaction vessel. The mixture was heated to approximately 90 C, which temperature was maintained throughout the duration of the,reaction Air was passed into the mixture via a fritted glass bubbler at such a rate as to ensure an exdes} of,molecular oxygen in the reaction zone at all 95 times The oxidation was continued for 6 hours The pressure was substantially 1

atmosphere' absolute Analysis of the product showed that a' substantial yield of terephthalic acid was obtained, together with p-toluic acid 100 as the principal by-product. EXAMPLE II A mixture of 27 2 grams of p-toluic acid dissolved in 100 ml n-octane and containing 0.1 % by weight cobalt naphthenate was 05oxidized with air at 1300 C for 17 hours at-'a pressure of r atmosphere absolute A 19 5 % yield of terephthalic acid was obtained. EXAMPLE III Parts by weight of p-methyltoluate, 50 110 parts by weight of n-decane and 0 3 parts by weight of cobalt stearate were charged to a reactor The mixture was heated to 130 C and oxidized with air at 1 atmosphere absolute pressure for 3 hours The product contained 115 % by weight of the monomethyl ester of terephthalic acid, which represented a 37 % conversion of p-methyltoluate. EXAMPLE IV A mixture containing equal weights of pseudo 120 cumene and n-decane, together with 0 1 % by weight of cobalt stearate, was oxidized'with air at 130 C and 1 atmosphere absolute pressure for 1 hour A 10 % yield of dibasic acid was obtained 125.


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