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CATALYSTTODAY

CATALYSTTODAY

Edition No 01 (November 2015)

Published by IIUM Chemistry Publishing

Catalyst Today is a science-based bulletin which focuses on industrial catalysis.

It is produced by the first batch students of Bachelor of Science (Applied

Chemistry) of International Islamic University Malaysia (IIUM).

The production was supervised by Dr Rosliza Salim who currently teaches the

students for Industrial Catalysis subject (SCH3053) in semester 1, 2015/2016

session.

EDITORIAL BOARD

FOREWORD

ENGINEERS OF ORGANISMS

METAL SALT CATALYST

PHOTOCATALYSIS

COMIC: ENZYMES IN ACTION

ZEOLITE

POSTER

MONSANTO PROCESS

HYDROFORMYLATION

THE RED STIMULANT

THE WACKER PROCESS

THE WRITERS

PEARL OF WISDOM

Assalamualaikum w.b.t.

I gratefully acknowledge my indebtness to my third year students from Department of

Chemistry for their input in this project. These students from Applied Chemistry have worked

a lot on the drafts, observations, and discussions to the topic of “homogeneous catalysis”,

which eventually condensed in this bulletin. The material presented in this bulletin was selected

based on the syllabus which includes eight topics of homogeneous catalytic reactions with

proven industrial applications and well-established mechanism. Besides getting deeper

understanding on industrial catalysis subject, this bulletin serves as the assignment which seeks

cooperation and teamwork of each group member to accomplish the task given.

I am very thankful and pleased with the commitment I received right from the start from the

editorial board members which did their best in designing, correcting and improving the

contents of this bulletin. More than anything else, I really hope that this bulletin would give a

clear view on the homogeneous catalysis and be a source of knowledge for the students and

also the readers.

Thank You.

Asst. Prof. Dr. Rosliza Mohd Salim

Advisor,

Catalysis Today.

FOREWORD

CATALYST T O D A Y

ENGINEERSO f o r g a n i s m

ENZYMESare famously known

as the “engineers” of an organism. Their roles and applications are

highly varied and yet its mechanistic

concepts are essentially similar.

By Izni, Atiqah, Khai, Anis Hamizah & Afiq Luqman

The Chemical Equation of hydrolysis of lactose by lactase

CATALYST T O D A Y

METALSALTS

C A T A L Y S T

CATALYST T O D A Y

CATALYST T O D A Y

Friedel-Crafts acylation (above) and alkylation (below)

AgTPA

CH3CN

80°C

R1 = aryl, cyclohexyl

R2, R3 = dialkyl, dibenzyl

R4 = alkyl, phenyl

PHOTOCATALYSISHave you eve r heard o f pho toca ta lys i s ?

What i s pho toca ta lys i s ?

By Huda, Sakinah, Hafiza, Fazleen & Fatin Nadiah

PHOTOCATALYSIS

CATALYST T O D A Y

,

•

•

Titanium dioxide is

one of the chemicals

added in paint and

coating system.

Titanium dioxide is

used in cosmetics

industry.

Titanium dioxide has

been well accepted in

food industry as additive

in various food products

that mainly for whitening

and texture.

It also applicable in

oral pharmaceutical

formulations

It ensures the longevity of

the paint. This catalyst also

has excellent light-scattering

properties which produce

the light colored paints that

can provides an impression

of openness and spacy

room.

Titanium oxide included as

protection of skin from

harmful effects of solar

ultraviolet radiation.

It is widely use on most

surfaces and items that are

white in color. This proved

that titanium dioxide is

harmless.

Nano-sized titanium dioxide

is considered as a non-

irritant and non-toxic

excipient. This is supported

by Pharmaceutical

Excipients handbook.

CATALYST T O D A Y

CATALYST T O D A Y

YAYY!!

%

By Hannan, Jazmi,

%

A Zeolite acting an a molecular sieve and a catalyst du-ring the formation of 1,4-dimethylbenzene from methyl-

benzene.

Structure The basic chemical structure of Zeolite

StelleritRudny, Kazakhstan

StelleritEdinband, Scotland

StilbiteAurangabad, India

NatroliteBombay, India

Hannan, Jazmi, Syafini, Nadia Aimi & Atif

CATALYST T O D A Y

,

, ,

CATALYST T O D A Y

CATALYST T O D A Y

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What is hydroformylation? It is a type of

oxo process which involves the catalyzed

conversion of olefins into aldehydes

through the addition of synthesis gases,

carbon monoxide (CO) and hydrogen (H2).

Hydroformylation process is important in

industries since the end products are

commercially used mainly in the plastics

and detergents manufacture.

Discovered in 1938 by Otto Roelen,

this process developed special significance

to industries since it produces a highly

versatile chemical intermediates, alde-

hydes that can be further transformed into

many other functional groups. It is called

as hydroformylation because the product

is derived from addition of the C-H bond of

formaldehyde across the carbon-carbon

double bond of the olefin. So far, the most

commonly used catalysts are cobalt

(HCo(CO)4) and rhodium with some

modifications such as cobalt phosphine

modified catalyst (HCo(CO)3(PR3)3), rho-

dium phosphine catalyst (HRh(CO)(PPh3)3)

and triphenylphosphinetrisulfonate

(TPPTS).

Now let’s take a look on the first

catalyst employed for hydroformylation

which is cobalt. This was based on Roelen's

original research whereby cobalt, under

H2/CO pressure of 200-300 bar and at 110-

180°C, produced HCo(CO)4 as an active

homogenous catalyst. The frequently use

starting material for HCo(CO)4 catalyzed

By Nur Hidayah, Nur Shafina, Farah Hani,Nafisah & Dayang Fatin Nadhirah

CATALYST T O D A Y

CATALYST T O D A Y

hydroformylation, Co2(CO)8 reacts with

hydrogen gas under catalysis reaction

conditions to form two equivalents

HCo(CO)4. However, HCo(CO)4 is only

stable under certain minimum CO partial

pressures at a given temperature. When

CO pressure increases, the reaction rate

decreases and give a high ratio of linear to

branched product. On the contrary, when

CO pressure decrease, the reaction rate

will increase, hence, more branched alkyl

through reverse ß-elimination will be

yielded.

Therefore, scientists had discovered

another transition metal that is suitable to

yield more aldehyde and gives high

regioselectivity of the expected product,

which is rhodium. In 2004, about 75% of

all hydroformylation processes are based

on rhodium triarylphosphine catalysts,

which excel with C8 or lower alkenes. The

initial catalyst system was derived from

Wilkinson's catalyst, RhCl(PPh3)3, but it

was rapidly discovered that halides were

inhibitors for hydroformylation. Hence,

HRh(CO)(PPh3)3 and Rh(acac)(CO)2 are two

common starting materials used as they

were halide-free materials.

COBALT CATALYST, HCo(Co)4 RHODIUM CATALYST, HRh(CO)(PPh3)3

Decompose to metallic cobalt at high temperature

and low CO pressure

Very selective in preferred linear aldehyde products

due to higher activity under milder condition

One advantage of the HCo(CO)4 technology is that

catalyst separation and recycling is well established

Very high linear to branched aldehyde

selectivities of 20:1 for a variety of 1-alkenes could be

obtained under ambient conditions (25° C, 1 bar 1:1

H2/CO)

The reaction conditions for HCo(CO)4

hydroformylation are largely governed by the thermal

instability of HCo(CO)4, which produces metallic cobalt

if the CO partial pressure is not kept high enough

In reaction, loss of PPh3 from HRh(CO)(PPh3)2

generates considerably more active, but less

regioselective hydroformylation catalysts. Addition of

excess phosphine ligand shifts the phosphine

dissociation equilibrium back towards the more

selective HRh(CO)(PPh3)2 catalyst.

Bimetallic pathway; general mechanism of hydroformylation

By Akmal, Hakimah, Hanis Azizan, Hafizah & Syahirah

Chlorotris(triphenylphosphine)rhodium (I) is known as

Wilkinson’s Catalyst. It is a type of homogeneous catalyst used in

hydrogenation of olefins. Rhodium in Wilkinson’s with +1

oxidation number has 16-electron configuration. Due to the

presence of vacant coordination site, Wilkinson’s catalyst can

accommodate an olefin molecule to form six-coordination square

planar molecular geometry.

CATALYST T O D A Y

Application of Wilkinson’s catalyst

Used in selective hydrogenation of alkene

and alkyne without affecting the functional

groups C=O, CN, NO2 and aryl CO2R

Preparation of Wilkinson’s Catalyst

Wilkinson’s catalyst can be prepared by

reacting rhodium chloride hydrate

(RhCl3.H2O) with excess triphenyl-

phosphine (PPh3) in ethanol (EtOH).

Shown below is the balance chemical

equation of the reaction:

RhCl3•3H2O + P(C6H5)3 ⟶ RhCl[P(C6H5)3]3

1. Reaction of sterically less hindered and less

substituted double bonds is more prefered.

2. Exocyclic double bonds will be hydrogenated

compared to endocyclic double bonds.

3. Cis alkenes will undergo hydrogenation

compared to trans alkenes.

4. Isolated double bonds will be hydrogenated

rapidly over conjugated dienes.

5. Terminal alkynes are hydrogenated faster than

terminal alkenes. Acidic alcoholic co-solvents

can be used to enhance the selectivity.

6. Functional groups like C=O, C=N, CO2R, aryl,

NO2, are unaffected.

7. Unsaturated substrates containing polar

functionality are hydrogenated faster.

Reaction of Wilkinson’s Catalyst

Wilkinson’s catalyst is mainly used in selective hydrogenation of alkene. The examples of the reaction are:

Place 5 mL of ethanol in a 10 mL round-

bottom flask equipped with a magnetic

stirring bar.

Attach a water condenser and place the apparatus on a heating block on a stirrer hot plate.

Heat the ethanol to just below its boiling

point (78 ºC).

Remove the condenser

momentarily, add 150 mg of

triphenylphosphine to the hot ethanol and stir until the solid is

dissolved.

A small amount of solid may remain at

this point.

Remove the condenser once

again, add 25 mg of hydrated rhodium(III)

chloride to the solution and continue

to stir.

Heat the solution to a gentle reflux for ~30

minutes.

Collect the product crystals by suction

filtration on a Hirsch funnel and dry the

crystals on the filter by continuous

suction.

Wilkinson’s catalyst powder

Preparation of Wilkinson’s catalyst

CATALYST T O D A Y

THE

PROCESS

The development of the Wacker process began in 1956 at Wacker Chemie. At that

time, the production of acetaldehyde is from acetylene. As time passed by, they

discovered that ethylene would be a cheaper raw-material, thus some investigation

about its potential uses have been carried out. As the research proceeded, the reaction

between ethylene and oxygen over palladium on carbon in a quest for ethylene oxide

unexpectedly resulted on formation of acetaldehyde. More research about this reaction

takes place resulted in a gas-phase reaction using a heterogeneous catalyst and lastly the

previous reaction was replaced by the water-based homogeneous system for the better

results.

Wacker process is a homogeneous olefin oxidation by tetrachloropalladate(II)

catalysts. Specifically, it is an industrial process for the conversion of ethylene into

acetaldehyde. The favorable economics of the process is due to the abundance of

ethylene present.

The discovery and development of Wacker process have been a great contribution

to the industrial process of synthesizing aldehyde from alkene. The modification of

industrial Wacker process to laboratory scale that is the Tsuji-Wacker Oxidation has led to

the synthesis of various kind of ketone. This process has shown an important process

driven by transition metal in the catalysis of organic compound. Catalyst is an ihsan

towards human being as it helps in the production of compound in a more convenient

way. One of the properties of a catalyst is to speed up the chemical reaction. This is also

what a human should be until he returns to Allah SWT to be questioned. A person should

strive for the best and manage their time wisely to be a productive and effective Muslim

as the responsibility of being a khalifah has been given by Allah SWT to the mankind.

By Fatin Nadzirah, Noor Raihan, Munirah, Noor Fatinie & Ashikin

CATALYST T O D A Y

The first step of this process involves the

formation of the olefin complex

[Cl3Pd(C2H4)]- . The metal activated olefin is

now ready for the nucleophilic attack by

water and this step will generate the

complex [Cl3Pd-CH2-CH2-OH]2-. β–hydrogen

transfer leads to the second olefin

complex. Alkyl complex with a hydroxyl

group as the substituent is then formed,

and this alkyl complex undergoes reductive

elimination to produce the desired

aldehyde and Pd(0). The presence of

copper(II) chloride in the reaction will

regenerate or reoxidise the Pd(0) to Pd2+. If

there is no oxidising agent to carry out this

step, the Pd(0) will be precipitated and the

reaction will stop after only one cycle.

Later, the Wacker Process was modified for

the use in experimental condition. It is

called Wacker- Tsuji oxidation. Variety of

ketones and aldehydes is synthesized by

using copper as redox co-catalyst as well as

palladium-catalyzed oxidation and

molecular oxygen as the oxidant. 10 % mol

PdCl2, stoichiometric CuCl, organic co-

solvent (often DMF), and 1 atmosphere of

oxygen gas is mixed with water. When high

oxygen pressure and sensible choice of

solvent is used, this process can undergo

without using co-catalyst, which is copper.

If copper is used, Copper(I) is rapidly

oxidized to Copper(II) by dissolving in

oxygen for 30 minutes in order to complete

the oxidation process. Copper(II) minimize

concentration of chloride in solution which

will induce syn-hydroxypalladation. Besides

water, peroxides also can be used as the

source of oxygen, in which the co-catalyst

is not needed. If the conditions fail, vast

modifications of reactions can be applied.

CATALYST T O D A Y

THE

WRITERS

CATALYST T O D A Y

THE

WRITERS

CATALYST T O D A Y

THE

WRITERS

CATALYST T O D A Y

THE

WRITERS

CATALYST T O D A Y

VERILY WITH THE HARDSHIP THERE IS RELIEF

[Qur’an 94:6]