Kirk Othmer PDF
Kirk Othmer PDF
Kirk Othmer PDF
ALCOHOLS, HIGHER
ALIPHATIC, SYNTHETIC
PROCESSES
1. Introduction
Higher aliphatic alcohols (C6 C18) are produced in a number of important indus-
trial processes using petroleum-based raw materials. These processes are sum-
marized in Table 1, as are the principal synthetic products and most important
feedstocks (qv). Worldwide capacity for all higher alcohols was approximately
5.3 million metric tons per annum in early 1990, 90% of which was petro-
Kirk-Othmer Encyclopedia of Chemical Technology. Copyright John Wiley & Sons, Inc. All rights reserved.
Vol. 2 ALCOHOLS, HIGHER ALIPHATIC, SYNTHETIC PROCESSES 27
leum-derived. Table 2 lists the major higher aliphatic alcohol producers in the
world in early 1990.
By far the largest volume synthetic alcohol is 2-ethylexanol [104-76-7],
C8H18O, used mainly in production of the poly(vinyl chloride) plasticizer bis(2-
ethylhexyl) phthalate [117-81-7], C24H38O4, commonly called dioctyl phthalate
[117-81-7] or DOP (see PLASTICIZERS). A number of other plasticizer primary
alcohols in the C6 C11 range are produced, as are large volumes of C10 C18
synthetic, mainly primary, alcohols used as intermediates to surfactants (qv)
Table 2 (Continued)
Company and Capacity
location 103 t/yr Alcohol products Feedstock
Table 2 (Continued)
Company and Capacity
location 103 t/yr Alcohol products Feedstock
Table 2 (Continued)
Company and Capacity
location 103 t/yr Alcohol products Feedstock
Table 2 (Continued)
Company and Capacity
location 103 t/yr Alcohol products Feedstock
for detergents. Other lower volume synthetic alcohol application areas include
solvents and specialty esters.
The Ziegler process, based on reactions discovered in the 1950s, produces predo-
minantly linear, primary alcohols having an even number of carbon atoms. The
process was commercialized by Continental Oil Company in the United States in
1962, by Condea Petrochemie in West Germany (a joint venture of Continental
Oil Company and Deutsche Erdol, A.G.) in 1964, by Ethyl Corporation in the
United States in 1965, and by the USSR in 1983.
Four chemical reactions are used to synthesize alcohols from aluminum
alkyls and ethylene (qv).
Triethylaluminum Preparation
2 Al 3 H2 6 C2 H4 ! 2 C2 H5 3 Al
Chain Growth
C2 H5 3 Al 3x C2 H4 ! C2 H5 C2 H4 x 3 Al
Oxidation
2 C2 H5 C2 H4 x 3 Al 3 O2 ! 2 Al OC2 H4 x C2 H5 3
Hydrolysis
2 Al OC2 H4 x C2 H5 3 3 H2 O ! 6 C2 H5 C2 H4 x OH Al2 O3
Fig. 1. Ziegler ethylene chain growth. Theoretical (Poisson) distribution of primary alco-
hols at (& ) 2.5, ( ) 3.0, (^) 3.5, and (. . 4 . .) 4.0 moles of ethylene per 13 mole
aluminum. Courtesy of Ethyl Corporation.
and (2) alpha olens can react with trialkylaluminum to produce branched alu-
minum alkyls and branched olens.
This second reaction leads to the small amount of branching (usually less than
5%) observed in the alcohol product. The alpha olens produced by the rst reac-
tion represent a loss unless recovered (8). Additionally, ethylene polymerization
34 ALCOHOLS, HIGHER ALIPHATIC, SYNTHETIC PROCESSES Vol. 2
Fig. 3. Flow diagram for the Vista Corporation primary alcohols plant, Lake Charles,
Louisiana. Courtesy of Vista Corporation.
Fig. 4. Flow diagram for the Ethyl Corporation primary alcohols plant, Houston, Texas.
Courtesy of Ethyl Corporation.
36 ALCOHOLS, HIGHER ALIPHATIC, SYNTHETIC PROCESSES Vol. 2
catalyst
RCH CH2 + CO + H2 RCH2CH2CHO + RCHCHO
CH3
catalyst
RCH2CH2CHO + RCHCHO + H2 RCH2CH2CH2OH + RCHCH2OH
CH3 CH3
These reactions are applicable to most monoolens and are used to obtain a large
number of commercial products.
3.2. Cobalt Catalyst, Two-Step, High Pressure Process. The olen,
with recycle and makeup cobalt catalyst at 0.11.0% concentration, is preheated
and fed continuously to the oxo reactor together with the synthesis gas at a
Vol. 2 ALCOHOLS, HIGHER ALIPHATIC, SYNTHETIC PROCESSES 37
Fig. 5. Flow diagram for oxo alcohol manufactured by the two-stage process.
Courtesy of the Ethyl Corporation.
39
Fig. 6. Flow diagram for the Shell Chemical alcohol-olen complex, Geismar, Louisi-
ana, and Stanlow, United Kingdom. Courtesy of the Shell Chemical Corporation and
the Ethyl Corporation.
40 ALCOHOLS, HIGHER ALIPHATIC, SYNTHETIC PROCESSES Vol. 2
Ethylene-Based Olens
Aluminum Alkyl Chain Growth. Ethyl, Chevron, and Mitsubishi Chemi-
cal manufacture higher, linear alpha olens from ethylene via chain growth on
triethylaluminum (15). The linear products are then used as oxo feedstock for
both plasticizer and detergent range alcohols; and because the feedstocks are lin-
ear, the linearity of the alcohol product, which has an entirely odd number of car-
bons, is a function of the oxo process employed. Alcohols are manufactured from
this type of olen by Sterling, Exxon, ICI, BASF, Oxochemie, and Mitsubishi
Chemical.
Catalytic Oligomerization. Shell Chemical provides C11 C14 linear inter-
nal olen feedstock for C12 C15 detergent oxo alcohol production from its SHOP
(Shell Higher Olen Process) plant (16,17). C9 C11 alcohols are also produced by
this process. Ethylene is rst oligomerized to linear, even carbonnumber alpha
olens using a nickel complex catalyst. After separation of portions of the a-
olens for sale, others, particularly C18 and higher, are catalytically isomerized
to internal olens, which are then disproportionated over a catalyst to a broad
mixture of linear internal olens. The desired C11 C14 fraction is separated;
the lighter and heavier fractions are recycled to the isomerization/disproportio-
nation section. The SHOP process has been described in detail in the literature
(18) and is shown schematically in Figure 6.
catalyst
2 CH3CH2CH2CHO CH3CH2CH2CH CCHO + H2O
CH2CH3
catalyst
CH3CH2CH2CH CCHO + 2 H2 CH3CH2CH2CH2CHCH2OH
CH2CH3 CH2CH3
In earlier studies (24), the reaction was carried out at temperatures above 2008C
under autogenous pressure conditions using alkali metal hydroxide or alkoxide
catalysts; signicant amounts of carboxylic acid, RCH2COOH, were formed as
were other by-products. More recent reports describe catalysts which minimize
by-products: MgOK2CO3 CuC2O2 (25), less basic but still requiring high tem-
peratures; Rh, Ir, Pt, or Ru complexes (26); and an alkali metal alkoxide plus Ni
or Pd (27), effective at much lower temperatures.
Some 2,0003,000 t/yr of these specialty alcohols are produced in the
United States (Exxon) and in Germany (Henkel) (28). Their high liquidity
because of branching permits use of less volatile, higher molecular weight mate-
rials, reported to be less irritating than the lower molecular weight linear alcohol
materials, in a variety of cosmetic products (29).
BIBLIOGRAPHY
Alcohols, Higher in ECT 1st ed., Vol. 1, pp. 315321, by H. B. McClure, Carbide and
Carbon Chemicals Corporation; Alcohols, Higher, Synthetic in ECT 2nd ed., Vol. 1,
44 ALCOHOLS, HIGHER ALIPHATIC, SYNTHETIC PROCESSES Vol. 2
CITED PUBLICATIONS
28. K. Noweck and H. Ridder, Ullmanns Encyclopedia of Industrial Chemistry, 5th ed.,
VCH Verlagsgesellschaft mbh, Weinheim, Germany, 1987, p. 288.
29. K. Klein, P. E. Bator, and S. Hans, Cosmetics and Toiletries, 95, 70 (1980); A. J.
OLenick, Jr., and R. E. Bilbo, Soap, Cosmet. Chem. Spec. 52 (April, 1987).
GENERAL REFERENCES
Oxo Processes
G. U. Ferguson, Chem. Ind. 11, 451 (1965).
H. Weber and J. Falbe, Ind. Eng. Chem. 62(4), 33 (Apr. 1970).
H. Weber, W. Dimmling, and A. M. Desal, Hydrocarbon Process. 55(4), 127 (1976).
46 ALCOHOLS, POLYHYDRIC Vol. 2
JOHN D. WAGNER
GEORGE R. LAPPIN
J. RICHARD ZIETZ
Ethyl Corporation