CycloheptaneFrom Wikipedia, the free encyclopedia

Cycloheptane

Identifiers

CAS number 291-64-5 

PubChem 9265

ChemSpider 8908 

ChEMBL CHEMBL453194 

Jmol-3D images Image 1

SMILES

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InChI

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Properties

Molecular formula C7H14

Molar mass 98.19 g mol−1

Density 0.8110 g/cm3

Melting point -12 °C, 261 K, 10 °F

Boiling point118.4 °C, 392 K, 245 °F

Solubility in water Immiscible

Solubility in ethanol Miscible

Hazards

EU classification Flammable (F)

Harmful (Xn)

Dangerous for

the environment (N)

Severe eye irritant, may cause corneal

clouding

NFPA 704

310

Flash point 6 °C

Related compounds

Related cycloalkanes Cyclohexane Cyclooctane

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Except where noted otherwise, data are given for materials in their standard

state (at 25   °C, 100   kPa)

Infobox references

Cycloheptane is a cycloalkane with the molecular formula C7H14. Cycloheptane is used as

a nonpolar solvent for the chemical industry and as anintermediate in the manufacture of chemicals

and pharmaceutical drugs. It may be derived by Clemmensen reduction from cycloheptanone. Cycloheptane

vapour is irritating to the eyes and may cause respiratory depression if inhaled in large quantity.[1]

Glucose (C6H12O6) is the principal source of energy for most living things. The body converts most dietary carbohydrates into glucose. Glucose is a monosaccharide, or simple sugar , a class of molecules that forms 5- and 6-sided rings, not unlike a benzene ring. In solution, the glucose molecule prefers a ring (cyclic) shape. Unlike benzene, not all points of its hexagon are carbon atoms.

Read more: Cyclic Structure of Glucose | eHow.com http://www.ehow.com/about_5498724_cyclic-structure-glucose.html#ixzz2K1ozPg77

s of Glucose?

Structure of Glucose

1. Cyclic Shape

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Outside of the open-chain, or dry, form, glucose is circular in structure. Its hexagonal shape has five carbon atoms and one oxygen atom at its six corners. Hydrogen and hydroxide groups (-OH) extend off four of these corner carbons. This circular version of glucose is usually in the "chair form" -- as opposed to the boat form -- so called because its sides fold in opposite directions (see diagram).

Glucose prefers the cyclic (circular) shape in solution, but at equilibrium some 0.02 percent of glucose rings are open, i.e., in the "dry form."

2. Polymers of Glucose Ringso Glucose is one of the simple sugars, along with galactose, fructose, xylose, and

ribose, among others. Technically, they don't hydrolyze (break down by addition of water) into simpler carbohydrate units. They are as simple as sugar gets.

Many complex carbohydrates (starch, glycogen, cellulose) are polymers (long chains) of the glucose ring, repeating over and over. This is easily  demonstrated using acid to hydrolyze them into monosaccharides.

Read more: Cyclic Structure of Glucose | eHow.com http://www.ehow.com/about_5498724_cyclic-structure- glucose.html#ixzz2K1p8g4ff

More Than One Cyclic Form

Glucose has two isomers (angular forms) with the chair form. The alpha and beta chair forms differ from each other by the orientation of one of the hydrogen-hydroxide orientations (see top diagram). A third cyclic isomer is called the "boat form," because the hexagon shape is cuplike.

Ring Points

Monosaccharides favor 5- and 6-sided rings because they bring the angles between the carbon bonds  closest to the ideal of 109.5 degrees. This is the natural angle for them, as can be seen from the separation angle of bonds in a methane (CH4) molecule, for example.

Six-membered cyclic structures like glucose are called "pyranose," after the hexagonal pyran molecule, which has 5 carbons and an oxygen in its ring just like glucose.

Representation of Cyclic Form Representation of the cyclic form can be done as a flat structure or in a way

that indicates the true angles of the bonds. The flat structure is called a "Haworth projection." "Ring conformers" present side views to make the angle difference, and the resulting puckering of the ring, clearer. A comparison can be found on the Michigan  State University website.

Read more: Cyclic Structure of Glucose | eHow.com http://www.ehow.com/about_5498724_cyclic-structure-glucose.html#ixzz2K1pMjx67