Study on the sio2 supported ionic liquid phase (SILP) catalysts for the hydroformylation of ethylene

MINISTRY OF EDUCATION AND TRAINING
HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY

STUDY ON THE SiO2 SUPPORTED IONIC LIQUID PHASE
(SILP) CATALYSTS
FOR THE HYDROFORMYLATION OF ETHYLENE
Speciality: Petrochemistry and catalysis for organic synthesis
Code: 62.44.35.01

CHEMISTRY DISSERTATION
A thesis submitted to Hanoi University of Science and Technology
for the degree of Doctor of Philosophy in Chemistry
By
Nguyen Thi Ha Hanh

SUPERVISORS : Assoc.Prof. Dr. Vu Dao Thang
Assoc.Prof. Dr. Le Minh Thang
INVITED SUPERVISOR: Prof. Rasmus Fehrmann


HANOI - 2011

ACKNOWLEDGMENTS

I would like to thank my supervisors, Assoc. Prof. Vu Dao Thang, Assoc.
Prof. Le Minh Thang, Prof. Rasmus Ferhmann, and Assoc. Prof. Anders Rissager
for their guidance, encouragement, and the academic and financial support in
accomplishing this work.
Many thanks to Dr. Olivier Nguyen Van Buu for introducing me to the airsensitive synthetic techniques, the hydroformylation reactor unit.
I also would like to thank my college - Msc.Truong Duc Duc for all his
help in the characterization of catalyst structures presented in this dissertation.

Very special thanks to my husband Quach and my daughter Minh Khue for
their love, support, and encouragement. And to my mom, and my dad– thanks for
being always there for me.
I would like to thank to my teachers at Department of Organic and
Petrochemical Technology, my colleges at the Laboratory of Petrochemical
Refining and Catalysis Materials for their supports, their commendation and their
discussions.
Acknowledgments are also extended to Danida Foundation for funding this
research.


CONTENTS
INTRODUCTION

1

CHAPTER 1: LITERATURE REVIEW
1.1
1.1.1.
1.1.2.
1.1.3.
1.1.4.

4
5
7
11
14

1.1.6

Hydroformylation of alkenes (Oxo Reaction)
The importance of hydroformylation products
The role of hydroformylation reaction
Catalysts for hydroformylation reaction
Recent trends in the heterogeneous hydroformylation
reaction
Heterogeneous
catalysts
for
vapor
phase
hydroformylation of alkenes
Mechanism of hydroformylation reaction

1.2.

SILP catalyst

26

1.2.1.
1.2.2
1.2.3
1.3

Composition of SILP catalysts
Synthesis of SILP catalysts
Catalytic activity of SILP catalysts
Aim of thesis

27
33
34
35

1.1.5.

17
21

CHAPTER 2: EXPERIMENT

2.1

Catalyst Synthesis

37

2.1.1

Chemicals

37

2.1.2

Synthesis procedures

38

2.2

Catalyst characterization

41

2.2.1

Characterization of surface properties by physical
adsorption
Infrared (IR) spectroscopy

41

2.2.2

43


2.2.3

Thermal analysis

44

2.2.4

SEM- TEM technichque

45

2.2.5

Nuclear magnetic resonance spectroscopy –NMR

49

2.3

Measurement of density of ionic liquid

50

2.4

Measuarement of catalytic activity

51

2.4.1

Hydroformylation of ethane

50

2.4.2

Hydroformylation of penten

53

2.4.3

Calculation of catalytic activities

54

CHAPTER 3: RESULTS AND DISCUSSION
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5

Catalyst characterization
The density of ionic liquid
NMR spectra of ligand TPPTS-Cs3
TPD NH3 of SiO2 support
Thermal analysis of IL, ligand and SILP catalyst
Surface area and physical adsorption properties of
SILP catalysts

57
57
59
59
60
66

3.1.6
3.1.7
3.1.8
3.2
3.2.1

FTIR characterization
SEM observation
TEM observation
Catalytic activity
Catalytic activity of the catalysts using ligand TPPTSCs3 for the hydroformylation of ethylene
Influence of ionic liquid loading content on acitivity
of SILP
Influence of Rhodium content on activity of SILP
Influence of ligand/Rh ratios on activity of SILP
catalyst
Deactivation of catalytic performance

70
75
79
82
83

3.2.1.1
3.2.1.2
3.2.1.3
3.2.1.4

84
87
90
88


3. 2.1.5
3.2.2
3.2.2.1
3.2.2.2
3.2.3

Activation energy
Catalytic activity of the catalysts using sulfoxantphos
ligand
Catalytic activity for the hydroformylation of ethylene
Catalytic activity for the hydroformylation of pentene
Discussion
CONCLUSION
References
Appendix

93
96
96
103
107
110
111

LIST OF TABLE
Table

Title

Page

1.1

Developments in hydroformylation processes

12

1.2

Classification of immobilised metal complex catalysts

17

1.4

Supported ionic liquid phase hydroformylation in ionic liquids

30

1.5

Supports used for SILP-catalysed hydroformylation of propene

32

2.1

Summary of synthesized catalysts

40

2.2

Retention times of reactants and products in the hydroformylation of
ethylene

53

2.3

Retention times of reactants and products in the hydroformylation of
pentene

54

3.1

Density of inonic liquid –[BMIM][n- C8H17OSO3],- at different temp

57

3.2

Weight loss due to the decomposition of IL in the samples with different
IL loadings, before and after use

65

3.3

Influence of IL loading on the Surface properties of SILPs

66

3.4

Surface properties of SILPs with different ligand and L/Rh ratios

67

3.5

Surface properties of SILP catalysts with different IL loading before and
after hydroformyl reaction (used)

68

3.6

Element compositions of different points indicated in figure 3.23

77

LIST OF FIGURES
Figure

Title

Page

1.1

Global consumption of 2–ethylhexanol for various applications (wt %)

6

1.2

Global consumption of n–butanol and iso–butanol (wt %)

7

1.3

Worldwide growth in the production of oxo products

8

1.4

Region wise production statistics for oxo products (2008)

9

1.5

Statistics of oxo products for Asia region (2003)

9

1.6

Worldwide oxo product derivatives distribution.

10

1.7

Production capacities for oxo products by worldwide known
industries

10

1.8

Hydroformylation reaction in biphasic medium.

16

1.9

Coordinative anchoring of a metal complex to the support surface

18

1.10

A schlenk line and schlenk tube

33

2.1

The Schlenk system to synthesize catalysts

39

2.2

BET plot

42

2.3

Ways to obtain vibrational spectroscopy: Transmission infrared

44

2.4

A themal Analysis Device

45

2.5

Effects produced by electron bombardment of a material

46

2.6.

Transmission electron microscope with all of its components

48

2.7

Spin state of a nulear

49

2.8

A description of the transition energy for a 31P nucleus

49


2.9

Scheme of the reactor set-up

52

2.10

Calibration curve for propanal

56

3.1

Density of inonic liquid [BMIM][n-C8H17OSO3], at different
Temperature

58

3.2

Ab. Viscosity of [BMIM][n-C8H17OSO3] at different temperature

58

3.3

NMR spectra of synthesized TPPTS-Cs3 ligand

60

3.4

TPD NH3 profiles of uncalcined and calcinated SiO2

61

3.5

TG-DSC profiles of [BMIM][n-C8H17OSO3] (nitrogen atmosphere,
heating rate: 5oC/min)

62

3.6

TG-DSC profile of ligand TPPTS-Cs3 (nitrogen atmosphere, heating
rate: 5oC/min)

63

3.7

TG-DSC profile of SILP -Cs-L/Rh10-IL10- Rh0.2 (nitrogen
atmosphere, heating rate: 5oC/min)

64

3.8

TG-DSC profile of SILP -Cs-L/Rh10-IL50- Rh0.2 (nitrogen
atmosphere, heating rate: 5oC/min)

64

3.9

TG-DSC profile of SILP -Cs-L/Rh10-IL30- Rh0.2 (nitrogen
atmosphere, heating rate: 5oC/min)

64

3.10

TG-DSC profile of SILP -SX-L/Rh10-IL10- Rh0.2 (nitrogen
atmosphere, heating rate: 5oC/min)

64

3.11

BJH desorption profiles of samples with different IL loading content
before (a) and after the reaction (used) (b)

69

3.12

FT-IR spectrum of SiO2, TPPTS-Cs3 ligand, IL and SILP-Cs-L/Rh10IL10-Rh0.2

70

3.13

FT-IR spectra of SILP catalyst using TPPTS ligand with different IL

71


loading contents
3.14

FT-IR spectra of SILP catalyst using TPPTS ligand with different
L/Rh ratios

72

3.15

FT-IR spectra of SILP catalyst using TPPTS ligand with different Rh
loading contents

72

3.16

FT-IR spectra of SILP catalysts with different IL loading before and
afer exposed to high temperatures of the reactions

73

3.17

FT-IR spectra of SILP catalysts with different Rh loading before and
afer exposed to high temperatures of the reactions

74

3.18

SEM images of SiO2 support

75

3.19

SEM images SILP-Cs-L/Rh10-IL5-Rh0.2

75

3.20

SEM images SILP-Cs-L/Rh10-IL10-Rh0.2

75

3.21

SEM images SILP-Cs-L/Rh10-IL20-Rh0.2

76

3.22

SEM images SILP-Cs-L/Rh10-IL50-Rh0.2

76

3.23

Positions for EDX measurement and EDX spectra of SILP-CsL/Rh10-IL10-Rh0.2 catalyst:

77

a) position for EDX measurement, b) EDX spectrum at S1, c) EDX
spectrum at S2, d) EDX spectrum at S3

3.24

SEM images of SILP-Cs-L/Rh10-IL5-Rh0.2 before and afer exposed
to high temperatures of the reactions

78

3.25

SEM images of SILP-Cs-L/Rh10-IL10-Rh0.2 before and afer
exposed to high temperatures of the reactions

79

3.26

SEM images of SILP-Cs-L/Rh10-IL50-Rh0.2 before and afer
exposed to high temperatures of the reactions

79


3.27

TEM images of SiO2 support

80

3.28

TEM images of SILP-Cs-L/Rh10-IL5-Rh0.2 before and afer exposed
to high temperatures of the reactions

80

3.29

TEM images of SILP-Cs-L/Rh10-IL10-Rh0.2 before and afer
exposed to high temperatures of the reactions

81

3.30

TEM images of SILP-Cs-L/Rh10-IL10-Rh0.2 before and afer

exposed to high temperatures of the reactions

81

3.31

TEM images of SILP catalysts with different Rh loading

82

3.32

Catalytic activity of SILP catalysts with different IL loading

85

3.33

Influence of IL loading contents on the maximum temperature which
the catalysts still work stably

85

3.34

Influence of IL loading content on the catalytic activity of SILP
catalysts

86

3.35

Influence of Rh content on the activity of SILP catalysts

87

3.36

Influence of ligand/Rh ratios on the catalytic activity of SILP
catalysts

88

3.37

Influence of ligand/Rh ratios on the maximum temperature which the
catalysts still work stably

89

3.38

TOF at 90oC (except for the sample with 50%IL, which TOF is at
80oC since the catalyst start to loose activity from 90oC already) of
the catalysts with different IL loading contents before and after the
exposition to high temperatures

90

3.39

TOF at 90oC of the catalysts with different Rh loading contents
before and after the exposition to high temperatures

91


3.40

Activity at 90oC of the catalyst SILP-Cs-L/Rh10-IL10-Rh0.2 before

92

and afer cofeed 10%V propanal in the feed stock
3.41

Influence of evacuation on the activity of deactivated catalysts

93

3.42

Arrhenius plots of the samples with different IL loading content

94

3.43

Arrhenius plots of the samples with different Rh loading content

95

3.44

Arrhenius plots of the samples with different L/Rh ratios

96

3.45

Influence of ethylene partial pressure on the TOF of the catalyst

97

3.46

Influence of ethylene partial pressure on the ethylene conversion

98

3.47

Influence of ethylene partial pressure on propanal selectivity

99

3.48

Catalytic activity on stream of the catalyst SILP-SX-L/Rh10-IL10Rh0.2 at different ethylene pressures

100

3.49

Influence of residence time on ethylene conversion

101

3.50

Influence of residence time on propanal selectivity

101

3.51

Influence of residence time on turn over frequency

101

3.52

Arrhenius plots to calculate activation energy of the catalyst SILPSX-L/Rh10-IL10-Rh0.2 at different ethylene pressures

103

3.53

Yield and selectivity at temperature of 125oC

104

3.54

Yield and selectivity at temperature of 116oC

104

3.55

Arrhenius plot for Rh-SILP-catalyzed hydroformylation

105

3.56

Selectivity (n/iso ratio) at different temperatures

105

3.57

Arrhenius plot for hydroformylation of pentene on the catalyst SILPSX-L/Rh10-IL10-Rh0.2 10bar syngas (alkene:CO:H2 = 1:1:1),
residence time =17s

106


LIST OF SCHEME
Scheme

Title

Page

1.1

Three stages of the catalyst development for the
hydroformylation reaction.

13

1.2

Hydroformylation of ethylene and propylene.

22

1.3:

Dissociative mechanism for hydroformylation cycle

22

1.4

Associative mechanism for hydroformylation cycle

23

1.5

Mechanism for ethylene hydroformylation, L=PPh3

24

1.6

The formation of heavy products (by-product)

26

1.7

Illustration of supported ionic liquid phase catalyst

27


LIST OF SYMBOLS AND ABBREVIATIONS
acac

acetyl-acetonate

BMIM

Butyl methyl imidazolium

FT-IR

Fourier transform infrared spectroscopy

Et

ethyl

IR

Infrared Spectroscopy

IL

Ionic liquid

L/B

linear to branched

Me

methyl

mL

milliliter

mM

Millimole

mol

mole

NMR

Nuclear magnetic resonance

Ph

phenyl

SEM

Scanning electron microscopy

SILP

Supported ionic liquid phase

TEM

Transmittance electron microscopy

TMGL

1,1,3,3-tetramethylguanidinium lactate

TOF

Turn-over-frequency

TPPTS-Cs3

Tri-cesium tris(m-sulfonatophenyl)phosphine

Y

Yield, mol-%


INTRODUCTION
Hydroformylation is one of the oldest and largest homogeneously catalyzed
reactions of olefins.
Hydroformylation is conducted in a mixture of reactants and products, and
as of 1984 in biphasic aqueous media to allow dissolution of Rh catalyst and
reactants in a homogeneous liquid phase. The catalysts used are homogeneous in
nature, dissolved into the solvent or reactant/product mixture. This poses
significant challenges related to separation, which is simplified in the biphasic
RCH/RP oxo-process. This process is based on aqueous biphasic catalysis and
uses tri(m-sulfonyl) triphenylphosphine (TPPTS), as the ligand and a water
soluble Rh metal as the catalyst.
Rhodium is more active than cobalt, but is also more expensive. Rhodium
is the catalyst of choice for conversion of low molecular weight alkenes, while
cobalt based catalysts are used for conversion of high molecular weight alkenes.
For example, Ruhrchemie/Rhone-Poulenc (RCH/RP) process has been applied
for hydroformylation of propene by Rh based catalysts.
Though, homogeneous catalysts give higher conversion and selectivity for
desired product in short reaction time as compared to heterogeneous catalyst
system, this have disadvantage in the separation of catalyst from the product

mixture. Thus, efforts are directed towards the heterogenization of rhodium
complex on the inorganic solid supports for hydroformylation of alkenes. In this
concern, more attention in the present thesis has been paid on literature review
related to the recent developments in the heterogenizaton of homogeneous
catalysts on the inorganic solid supports for hydroformylation of alkenes.
On the other hand, ethylene, propene, butene are light alkene, but only the
hydroformylation of propene, butene reaction in biphasic medium very
successfully.
The main product - propanal derived from the hydroformylation of
ethylene, however, bears a significant miscibility with water. If the reaction
could happen in aqueous- biphasic like propene reaction, there would be some
problems:
- Water in the aldehyde cannot be removed by distillation, due to the
formation of azeotropic mixtures,
1


- Together with the water dissolved in the propanal, a significant amount of
catalyst is transported out of the reactor; a recovery of this portion of the catalyst
is difficult.
Athough, the hydroformylation of ethylene itself in the water-based
Rh/TPPTS system is quite fast, ethylene can soluble in the water phase, is
counterbalanced by the unfavorably high solubility of water in propanal. For this
reason the hydroformylation of ethylene is performed in homogeneous Rh/TPP
systems.
Thus, if the hydroformyltion of ethylene reaction can be done by using
SILP catalyst as heterogenous way, it will be a promising way to apply in
industry scale.
The goal of this research was to develop a solid catalyst for heterogeneous
hydroformylation of ethylene. Rhodium is the most active transition metal for

hydroformylation and it was obvious choice for the catalytic metals in the
preparation of the solid catalysts. Silica was chosen, because it is an inert,
available support material widely applied in catalysis.
Ligands change the electronic and steric properties of the catalyst complex.
Two ligands (TPPTS-Cs3 and sulfoxantphos) were chosen to evaluate their
activity in ethylene hydroformylation.
The thesis includes three chapters. The first chapter summarizes the aspects
about the hydroformylation process, synthesis, the structure, the catalytic
property of SILP catalyst in the literature. The second chapter describes the
catalysis synthesis and introduces basic principles of the physico-chemical
methods used in the thesis.
The chapter III is focused on the characterization of SILP, the catalytic
activity of SILP with two above mentioned ligands.
Final is the general conclusions of the performed work.

2


CHAPTER 1: LITERATURE REVIEW
Development of green catalytic routes for the synthesis of commercially
important chemicals is a rewarding endeavor from environment and economic
point of view. Green chemistry comprises designing, development and
implementation of chemical products and processes to reduce or eliminate the
use and generation of substances hazardous to the human health and
environment. It is an innovative, non–regulatory, economically driven approach
toward sustainability. Green technology is receiving significant attention as the
awareness about environmental issues has increased. The concept for the design
of environmentally benign products and processes is embodied in the 12
Principles of Green Chemistry as follow [11].
1. Waste prevention instead of remediation

2. Atom efficiency
3. Use of less hazardous/toxic chemicals
4. Design safer chemicals and products
5. Use innocuous solvents and reaction conditions
6. Design energy efficient processes
7. Preferably renewable raw materials
8. Shorter synthesis route and avoid derivatization
9. Use catalyst instead of stoichiometric reagents
10. Design products for degradation after use
11. Real time analytical methodologies for pollution prevention
12. Inherently safer processes to minimize the potentials for accidents
Catalysis plays a vital role in production of wide variety of products, which
are having applications in drugs, plastics, agrochemicals, perfumery, detergents,
food, clothing, fuels etc. [90]. In addition to, it plays an important role in the
balance of ecology and environment by providing cleaner alternative routes to
stoichiometric technologies. Green catalytic process efficiently utilize all the
atoms of raw materials, eliminates waste and avoids the use of toxic and/or
3


hazardous reagents and solvents in the manufacture and application of chemical
products.
Hydroformylation is an important commercial process for the conversion of
alkenes, carbon monoxide and hydrogen into aldehydes to be further used in the
production of various chemicals. The industrial processes operate in a
homogeneous mode. Therefore, the development of a solid catalyst would solve
problems related to catalyst separation and thus, contribute to decrease waste
from these chemical processes. This section summarizes the basic knowledge in
the field of hydroformylation of alkenes in liquid phase and especially in the gas
phase condition.

1.1 Hydroformylation of alkenes (Oxo Reaction)
Hydroformylation is one of the oldest and largest homogeneously catalyzed
reactions of olefins. The reaction was first discovered in 1938 by Roelen while
working for Ruhrchemie in Germany. Roelen investigated the effect of added
olefins to cobalt catalysts and identified aldehydes as one of the oxygen
containing components. H2 and CO can add across the double bond of olefins to
form aldehydes in the presence of a Co (or Rh) catalyst [42, 93].
The process is frequently referred to as the “Oxo” process, with Oxo being
short for Oxonation, i.e. the addition of oxygen to a molecule. However, the term
hydroformylation is descriptively more accurate and more useful in
characterizing this type of reaction catalyzed by various transition metal
complexes because during the reaction a hydrogen atom and a formyl group are
added to the olefinic double bond.
RCH2 = CH2 + CO + H2→RCH2CH2CHO + RCH(CH3)CHO (Eq.1.1)
“normal”

“branched”

The relative amounts of normal- and branched-chain aldehydes
produced depend on the identity of R and other constituents of the reaction
mixture. Normal-chain aldehydes, the more desirable products, usually are
hydrogenated, affording straight-chain alcohols, or self-condensed, affording
more complex aldehydes. With a terminal alkene as substrate, the
normal/branched ratio is an important parameter in the industrial
hydroformylation process; generally speaking, the better catalytic
performance, the higher the ratio, although significant markets have

4

developed for the branched aldehydes. In addition to linear terminal olefins,
a wide variety of different olefins have been successfully hydroformylated,
e.g. linear internal olefins, unsaturated alcohols, phenols, ethers, and amides.
Hydroformylation, the reaction of an alkene with syngas (carbon
monoxide and hydrogen) to form aldehydes and alcohols, is an
homogeneously catalyzed reaction performed industrially on a large scale.
Rhodium and cobalt carbonyls have been used for a long time, but such a
homogeneous process includes a difficult and expensive step of catalyst
recovery. Consequently it has been attempted to avoid this step by using
heterogeneous catalysts.
The first generation of hydroformylation catalysts was based on cobalt
carbonyl without phosphine ligand [26, 42, 93]. The conditions were harsh,
as activity of cobalt is low. The process was used both for lower as for
higher alkenes, and notably also internal alkenes give mainly linear product
aldehyde. Initially rhodium catalyzed reaction seemed slow, because the
formation of rhodium hydrides requires high pressures of hydrogen.
A nearly commercial application of phosphine-free rhodium was by
Mitsubishifor the hydroformylation of higher 1-alkenes in 1970. Since
Shell's report on the use of phosphines in this process [93], many industries
started applying phosphine ligands in the rhodium process as well. While
alkylphosphines are the ligands of choice for cobalt, they lead to slow
catalysis when applied in rhodium catalysis. In the mid-sixties the work of
Wilkinson showed that arylphosphines should be used for rhodium and that
even at very mild conditions very active catalysts can be obtained [37, 114].

1.1.1. The Importance of Hydroformylation Products
World production and consumption of hydroformylation (oxo) chemicals is
more than 8.8 million metric tons per year finding use in the manufacture of
solvents, soaps, detergents, plasticizers and various intermediates for fine and
perfumery chemical industry. n–propanol and n–propyl acetate produced from

ethylene hydroformylation are used in flexographic and gravure inks, which
require volatile solvents to prevent spreading and ink accumulation on printing
processes [32,59,104]. n–propanol is also used as a solvent, pesticide
intermediate, precursor for glycol ether, surface coating applications, grain and
5


food preservatives, herbicides, etc.
Over 90% of world consumption of n–butanal, which is produced by
hydroformylation of propylene, is for the production of 2–ethylhexanol (2–EH)
and n–butanol. The butanal is mainly applied as an intermediate for the
production of plasticizers, rubber accelerators, synthetic resins, solvents and high
molecular weight polymers. The reason for high production and demand of C4
aldehydes is due to its use in the production of 2–ethylhexanol (2–EH). About
60% of the total C4 aldehydes production amount (or about 70% of the n–butanal
production capacity) is consumed for the synthesis of 2–ethylhexanol. 2–
Ethylhexanol is used for the production of dioctyl phthalate and other
plasticizers, coatings, adhesives, stabilizers, low volatility solvent, perfumery
and specialty chemicals (Figure 1.1). 2–ethylhexanol derivatives are used as an
additive for diesel fuel to reduce engine emissions and for lube and mining oils
to improve their performance.

Figure 1.1. Global consumption of 2–ethylhexanol for various applications
(wt %) [32].

n–Butanol is a versatile intermediate for chemical industry. It reacts with
acids to yield esters and with oxides to yield glycol ethers. n–Butanol is an
intermediate chemical for the synthesis of esters like butyl acetate, butyl acrylate,
butyl methacrylate, etc. and these esters are used as solvents for coating. Other
applications of n–butanol are solvent, cleaning fluids, herbicides, dyes, printing

inks, personal care products, pharmaceuticals, plasticizers, textiles and lube
additives. The global consumption of the butanol is shown in Figure 1.2.
6


Figure 1.2. Global consumption of n–butanol and iso–butanol (wt %)[32]

C5 valeraldehyde derivatives are used predominantly to make lube oil
additives, automotive anti–wear applications, aeromotive synthetic lube
formulation and refrigerant lubricants. n–valeric acid, which is prepared from the
hydroformylation of butene followed by oxidation, is used for the synthesis of
lubricants, biodegradable solvents, plasticizers, perfumery and pharmaceutical
chemicals. C6-15 oxo alcohols are used in the fine chemicals and perfumery
industry, for the synthesis of neopolyol esters plasticizers and detergent
applications [105].
1.1.2. The role of Hydroformylation Reaction in Industry
The fast growing market for the oxo products plays an important role in the
hydroformylation processes. Figure 1.3 shows the growth in the production of
oxo products around the world [32].
As seen from Figure 1.3 and 1.4, Asia, North America and Western Europe
are contributing 32%, 23% and 30%, respectively to the world production
capacity of oxo products and are major oxo producers today. USA and Germany
with 23% and 21% of world’s production are also leading producers. Within
Asia, Japan, South Korea and China are the major manufacturers with as many
as five other countries engaged in the production of oxo products (Figure 1.5).
Vietnam is still an imported country, production of oxo products has not been
started yet, most of chemicals are imported. Between 1998 and 2002,
7

approximately 1.8 million metric tons of oxo chemical capacity was added,
mainly in Southeast Asia.
Demand for oxo chemicals in the United States is expected to grow
moderately, at an average annual rate of almost 2% during 2008–2013. The longterm prospects for oxo chemicals in Western Europe improved considerably
during 2005–2008, as consolidations and capacity reductions resulted in
improved efficiencies and capacity utilization. The commissioning of plants for
2-PH and additional isononyl alcohol (INA) capacity helped reduce the former
reliance on 2-EH. Western European consumption of oxo chemicals is forecast
to grow at an average annual rate of 2.0% during 2008–2013. Japanese
consumption is forecast to experience 0.9% average annual growth during 2008–
2013. Other Asian consumption, excluding Japan, is expected to grow at 5.0%
annually during the same period; China, India and Taiwan are the main growth
markets in this region. Middle Eastern consumption of oxo chemicals is forecast
to grow significantly at an average annual rate of 4.8% during 2008–2013, albeit
from a small base, largely as a result of increased n-butanol demand for n-butyl
acrylate by late 2010.
These data show that Asia has been the main growth center for these
chemicals during last five year with North America and Western Europe
showing stagnancy. It is estimated that in the coming five years too, Asia will
witness the growth in oxo products with only a small increase in production
capacities in other countries.

8


Figure 1.3. Worldwide growth in the production of oxo products [32]

Figure 1.4. World concumption of oxo products (2008)[106].

The worldwide oxo product derivatives distribution is shown in Figure 1.6.

The production rate of 2–ethylhexanol is high among all oxo derivatives, which
is mostly consumed by the plastic industry, followed by production of butanol.

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Figure 1.5. Productions of oxo products in Asia region (2003) [32].

Figure 1.6. Worldwide oxo product derivatives distribution [32].

The detergent grade alcohols also have significant contribution in the world
market, which are produced by oxo reaction. Figure 1.7 gives the estimated
production capacities for the oxo products via hydroformylation reaction by
worldwide known industries. It is observed from these data that around 57% of
the oxo products are produced by seven big companies namely BASF, Exxon,
EON, Celanese, Dow, Eastman and Kyowo Hakko [32].
10


Figure 1.7. Production capacities for oxo products by worldwide known
industries [32].

1.1.3. Catalysts for Hydroformylation Reaction
The hydroformylation catalysts, typically, consist of a transition metal atom
(M), especially from the platinum group metals. These transition metal
complexes interact with carbonmonoxide and hydrogen to form metal carbonyl
hydride species, which is an active hydroformylation catalyst. Typically,
complexes containing carbonyl ligands are known as unmodified catalysts. On
the other hand, the introduction of tailor–made ligand to the transition metals are
known as the modified catalysts.

Three developmental stages for hydroformylation catalysts are reported in
the literature. The first stage of hydroformylation was exclusively based on
cobalt (Co) containing catalyst. The catalytic active species for hydroformylation
reaction was the cobalt carbonyl hydrides in the pressure range of 240–300 bar at
150–200 °C temperature. Separation of products from the reaction mixture,
severe reaction conditions and low activities of catalysts were the main
limitations of this stage’s processes. The research efforts led phosphine replacing
11


carbonyl complexes as an electron donating ligand and this emerged as a
fundamental step in metal carbonyl catalyzed reaction, which imparted ability to
the scientists to tailor–make catalyst by modifying the electronic and steric
properties of the ligand.
The second stage of hydroformylation reaction was the combined
development in ligand modification and replacement of cobalt rhodium (Rh)
metal. It took almost a decade of research before first rhodium catalyst based
commercial process was launched in 1974 and the process was termed as Low
Pressure Oxo (LPO) process. Compared to cobalt based processes, many
advances were made in the second developmental stage of hydroformylation,
especially with respect to material and energy utilization. Thus, second stage of
hydroformylation was concluded with development of more effective Rh–
phosphine catalyst. However, the industrial problems of first stage such as,
separation of products from reaction mixture, catalyst recovery, loss of costly
metals, use of corrosive solvents, etc. continued in the second stage too.
The third stage, can be called a break-through in hydroformylation
process

-

two-phase

catalysis

(biphasic

or

liquid

multi-phase

systems

hydroformylation), because of finding a way of separating the catalyst and the

reaction products under mild conditions that is ecologically as well as
economically efficient. The fundamental idea consisted in applying water–
soluble catalysts by ligand modification and thus transferring the
hydroformylation into aqueous phase. With the help of such catalysts,
separations of desired products have become an easy task. The idea of applying
water–soluble Rh–complex as a catalyst for the hydroformylation of propylene
and 1–butene was taken up and commercialized by Ruhrchemie AG [29]. The
first plant was commissioned in 1984, only two years after the development on
laboratory scale, followed by rapid further increases in capacity to more than 3 x
6

10 tons/year. An additional unit for the production of n–pentanal (n–
valeraldehyde) from 1–butene [95] has been brought on stream in 1995. The
developments of hydroformylation processes in different stages are shown in

Table 1.1 and the catalysts used are presented in Scheme 1.1.

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