Catalyst Today Issue 01
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Transcript of Catalyst Today Issue 01
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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
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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
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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]