Preparation of ethanol and higher alcohols from lower carbon number alcohols

A process for forming an alcohol fraction boiling in the range of motor gasoline that is enriched in higher alcohols, comprises contacting a mixture of hydrogen, carbon monoxide and a lower alkanol with a catalyst comprising: PA0 (1) a first component comprising molybdenum, tungsten or a mixture thereof in free or combined form; PA0 (2) a second component comprising an alkali or alkaline earth element or a mixture thereof in free or combined form; PA0 (3) an optional third component comprising cobalt, nickel or iron or a mixture thereof in free or combined form; and PA0 (4) an optional fourth component comprising a support, under conditions sufficient to convert at least some of the one or more lower alcohols to higher alcohols.

FIELD OF THE INVENTION 
This invention relates to a process for making ethanol and higher alcohols 
from alcohols with lower carbon numbers. 
BACKGROUND OF THE INVENTION 
There are several significant processes for making mixed alcohols from 
synthesis gas or H.sub.2 /CO. For example, British patent publication No. 
2,083,469 discloses such a process wherein the catalyst is based on 
chromium, zinc and at least one alkali metal. While the applicants claim 
that the mixed alcohols may contain from 35 to 75 weight percent methanol, 
the examples given vary from 43 to 69 percent methanol. 
The Dow Chemical Company in U.S. Ser. No. 622,029, filed June 18, 1984, now 
abandoned which is a continuation-in-part of Ser. No. 476,674 which was 
filed March 18, 1983, now abandoned, both of which are hereby incorporated 
by reference, and PCT application 84.00405 filed Mar. 16, 1984 published 
Sept. 27, 1984 as 84/03696 which is also incorporated herein by reference, 
discloses a process for making mixed alcohols from synthesis gas using a 
molybdenum-based catalyst. 
Substantial methanol may be coproduced with the higher alcohols in these 
processes. The coproduction of methanol may be undesirable for a number of 
reasons. At the time this application is being filed, methanol prices are 
depressed due to oversupply and it is available for a price substantially 
lower than any of the higher alcohols. 
The major targeted use for the synthesized mixed alcohols is as a fuel 
additive in gasoline engines. Some have held that methanol is an 
undesirable component for a number of reasons. When blended in hydrocarbon 
gasolines, methanol is said to increase evaporative emissions and to be 
liable to phase separation which may lead to corrosion of fuel systems and 
engine components and possible inferior drivability. While these 
deficiencies may be in dispute, it is at least desirable to minimize or at 
least reduce coproduced methanol. 
One remedy is to make a lower percentage of methanol in the mixed alcohols. 
U.S. Ser. No. 635,999, filed July 30, 1984, now abandoned, which is 
incorporated herein by reference, discloses that one may vary the ratio of 
methanol to higher alcohols in a mixed alcohols process using a 
molybdenum-based catalyst by adjusting the concentration of a 
sulfur-releasing substance in the feed. As the concentration of the 
sulfur-releasing substance is adjusted upwards, the percentage of methanol 
in the mixed alcohols produced is lowered. However, in addition, as the 
sulfur concentration of the feed is increased, the catalyst becomes less 
active for making alcohols. The minimum practically obtainable weight 
percentage of methanol in the mixed alcohols at the time of this filing is 
about 30 percent by this method. 
One may also lower the percentage of methanol in the mixed alcohols through 
catalyst selection. In U.S. Ser. No. 636,000, filed July 30, 1984, now 
abandoned, which is hereby incorporated by reference, the applicant 
discloses a catalyst which comprises a first component which may be 
molybdenum or tungsten, a second component which may be iron, cobalt or 
nickel, a third component comprising an alkali or alkaline earth element 
with an optional fourth component being a support. Within certain limits 
as one increases the ratio of the second component to the first component, 
the percentage of methanol in the mixed alcohols decreases. One may 
achieve a methanol content as low as about 10 weight percent at practical 
productivities using the disclosed catalyst. 
It would be desirable to make a lower methanol to higher alcohols ratio at 
a high productivity and without lowering the activity or selectivity of 
the catalyst to mixed alcohols. 
OBJECTS OF THE INVENTION 
It is an object of this invention to make a C.sub.2 -C.sub.6 alcohol from a 
lower carbon number alcohol. It is a preferred object of this invention to 
make a mixed alcohols stream with a lower methanol to higher alcohols 
ratio. It is a more preferred object of the invention to make a mixed 
alcohol stream with less than 50 weight percent methanol while retaining 
high activity and selectivity to mixed alcohols. It is an alternative 
object of this invention to convert lower value methanol into higher 
valued higher alcohols. 
SUMMARY OF THE INVENTION 
These and other objects of the invention may be achieved by a process 
comprising contacting a mixture of hydrogen, carbon monoxide and one or 
more lower alcohols with a heterogeneous catalyst comprising: 
(1) a first component comprising molybdenum, tungsten or a mixture thereof 
in free or combined form; 
(2) a second component comprising an alkali or alkaline earth element or a 
mixture thereof in free or combined form; 
(3) an optional third component comprising cobalt, nickel or iron or a 
mixture thereof in free or combined form; and 
(4) an optional fourth component comprising a support; under conditions 
sufficient to convert at least part of the one or more lower alcohols to 
higher alcohols. 
It is a feature of this invention that methanol or another lower alcohol is 
combined with the H.sub.2 /CO feed. The advantage of the invention is that 
the lower value methanol or other alcohols are apparently converted to a 
higher homologue. While the process appears to be a homologation, the 
applicants do not wish to be limited to the possibility of this mechanism 
since the exact mechanism is uncertain. 
DETAILED DESCRIPTION OF THE INVENTION 
The hydrogen and carbon monoxide required for this process may be obtained 
by methods known in the art. Examples are gasification of 
hydrocarbonaceous materials such as coal, high specific gravity oil, or 
natural gas; as a by-product of partial combustion cracking of 
hydrocarbons; by steam reforming of liquid or gaseous hydrocarbons; 
through the water-gas shift reaction; or some combination of these. The 
two components may also be generated separately and combined for the 
subject reaction. The molar ratio of hydrogen to carbon monoxide in the 
feed gas which contacts the catalyst ranges generally from about 0.25 to 
about 100, preferably from about 0.5 to about 5, and more preferably from 
about 0.7 to about 3. A most preferred range is from about 0.7 to about 
1.5. 
The one or more lower alcohols are preferably C.sub.1 -C.sub.5 alcohols. 
Exemplary alcohols include: aliphatic alcohols such as methanol, ethanol, 
1-propanol, 2-propanol, n-butanol, 2-butanol, 2-methyl-2-propanol, and 
higher homologues; dihydroxy alcohols such as ethylene glycol, propylene 
glycol and 1,4-dihydroxybutane; trihydroxy alcohols such as glycerine; 
cycloaliphatic alcohols such as cyclohexanol and substituted 
cyclohexanols, and phenols and substituted phenols. The lower alcohols may 
be substituted. Preferably, the substituents are inert. By inert it is 
meant that the substituent is not altered under the conditions experienced 
by the lower alcohol during the reaction. 
Preferred lower alcohols are the C.sub.1 -C.sub.3 alcohols. Methanol is 
most preferred because its higher homologues are substantially more 
valuable. A particularly preferred lower alcohol is one formed by 
fractionating the mixed alcohol product of the process to remove the 
methanol which is then recycled back into the feed. One may substantially 
reduce the methanol content of the mixed alcohols using this scheme or may 
if one wishes recycle the methanol to extinction. Alternatively, one may 
bring in methanol from outside the process to add to the feed. This may 
not decrease the ratio of methanol to higher alcohols in the product but 
instead may act to upgrade the purchased methanol feed. 
The first component of the catalyst preferably consists essentially of at 
least one member selected from the group consisting of molybdenum and 
tungsten in free or combined form. Molybdenum is preferred. 
The molybdenum or tungsten may be present in the catalyst in "free or 
combined form" which means that it may be present as a metal, an alloy or 
a compound of the element. Representative compounds include the sulfides, 
carbides, oxides, halides, nitrides, borides, salicylides, oxyhalides, 
carboxylates such as acetates, acetylacetonates, oxalates, etc., carbonyls 
and the like. Representative compounds also include the elements in 
anionic form such as molybdates, phosphomolybdates, tungstates, 
phosphotungstates, and the like and include the alkali, alkaline earth, 
rare earth and actinide series of salts of these anions. The sulfides, 
carbonyls, carbides and oxides are preferred, with the sulfides being most 
preferred. 
The second component of th catalyst preferably consists essentially of at 
least one member selected from the group consisting of the alkali elements 
or alkaline earth elements in free or combined form. Alkali elements 
include lithium, sodium, potassium, rubidium and cesium. Alkaline earth 
elements include magnesium, calcium, strontium and barium. Alkali elements 
and in particular cesium and potassium are preferred. Potassium is most 
preferred. 
The second component or promoter may be present in free or combined form as 
a metal, oxide, hydroxide, sulfide or as a salt or a combination of these. 
The alkaline promoter is preferably present at a level sufficient to 
render the catalyst neutral or basic. 
The second component may be added as an ingredient to the molybdenum or 
tungsten component or to the support or may be a part of one of the other 
components such as sodium or potassium molybdate or as an integral part of 
the support. For example, carbon supports prepared from coconut shells 
often contain small amounts of alkali metal oxides or hydroxides or the 
support may contain a substantial amount of the promoter such as when the 
support is magnesia. 
The third optional component of the catalyst preferably consists 
essentially of at least one element selected from the group consisting of 
iron, cobalt or nickel in free or combined form. Cobalt and nickel are 
preferred. 
Representative compounds include the sulfides, carbides, oxides, halides, 
nitrides, borides, salicylides, oxyhalides, carboxylates such as acetates, 
acetylacetonates, oxalates, etc., carbonyls and the like. Representative 
compounds also include the elements combined with first component elements 
in the anionic form such as iron, cobalt or nickel molybdates, 
phosphomolybdates, tungstates, phosphotungstates and the like. The 
sulfides, carbonyls, carbides and oxides are preferred with the sulfides 
being most preferred. 
A fourth optional component of the catalyst may be a support which may 
assume any physical form such as a powder, pellets, granules, beads, 
extrudates, etc. The supports may be coprecipitated with the active metal 
species or the support in powder form may be treated with an active metal 
species and then used as is or formed into the aforementioned shapes or 
the support may be formed into the aforementioned shapes and then treated 
with the active catalytic species. 
The first three components may be dispersed on the support by methods known 
in the art. Examples include: impregnation from solution which may be 
followed by conversion to the active species, vapor deposition, intimate 
physical mixing, sulfiding of other first or second component species, 
precipitation of sulfides in the presence of the support and the like. One 
or more of these methods may be used. 
Exemplary support materials include: the aluminas, basic oxides, silicas, 
carbons or suitable solid compounds of magnesium, calcium, strontium, 
barium, scandium, yttrium, lanthanum and the rare earths, titanium, 
zirconium, hafnium, vanadium, niobium, tantalum, thorium, uranium and 
zinc. Oxides are exemplary compounds. Preferably, the supports are neutral 
or basic or may be rendered neutral or basic by addition of the alkaline 
promoters. The aluminas include the alpha, gamma and eta types, the 
silicas include for example silica gel, diatomaceous earth and crystalline 
silicates. 
The carbon supports, which are preferred, include activated carbons such as 
those prepared from coals and coal-like materials, petroleum-derived 
carbons and animal- and vegetable-derived carbons. Preferably, the carbon 
support will have a surface area of 1 to 1500 m.sup.2 /g, more preferably 
10 to 1000 m.sup.2 /g and most preferably 100 to 500 m.sup.2 /g, as 
measured by the BET nitrogen test. Exemplary carbon supports include 
coconut shell charcoal, coals, petroleum cokes, carbons formed by 
pyrolyzing materials such as vinylidene chloride polymer beads, coal, 
petroleum coke, lignite, bones, wood, lignin, nut shells, petroleum 
residues, charcoals, etc. 
For several reasons, the preferred form of the catalyst is the alkalized 
agglomerated sulfide. Certain forms of cobalt/molybdenum sulfide are more 
preferred. Most preferred is agglomerated, cobalt/molybdenum sulfide in 
which the cobalt and molybdenum sulfides are coprecipitated. 
Methods for making sulfide catalysts are disclosed generally at pages 23-34 
of Sulfide Catalysts, Their Properties and Applications, O. Weisser and S. 
Landa, Pergamon Press, N.Y., 1973, the whole of which is incorporated 
herein by reference. 
Sulfide catalysts may be made by precipitating iron, cobalt or nickel 
sulfide in the presence of ammonium tetrathiomolybdate or other 
thiomolybdates or thiotungstates and thereafter thermally treating the 
mixture to convert the thiomolybdate or thiotungstate salt to the sulfide. 
Alternatively, one may use the methods disclosed in U.S. Pat. Nos. 
4,243,553 and 4,243,554, which are hereby incorporated by reference. 
Combined first and third component sulfides are available commercially 
from several catalyst manufacturers. 
Cobalt and molybdenum may be impregnated as salts on a support, then 
calcined to the oxide and then sulfided with hydrogen sulfide as taught in 
G.B. patent publication No. 2,065,491 which is incorporated herein by 
reference. A cobalt/molybdenum sulfide may be precipitated directly onto a 
support, but the unsupported cobalt/molybdenum sulfide is preferred. Other 
combinations of first and second component sulfides may be similarly made. 
An unsupported catalyst preferably has a surface area of at least about 10 
m.sup.2 /g and more preferably more than 20 m.sup.2 /g as measured by the 
BET nitrogen surface area test. 
The preferred method of making a cobalt/molybdenum sulfide or other first 
and third component sulfide is by adding solutions of ammonium 
tetrathiomolybdate or other equivalent salt and a cobalt or nickel salt 
such as the acetate more or less simultaneously to 30 percent acetic acid. 
This results in a coprecipitation of cobalt or nickel/molybdenum sulfide. 
By varying the ratios of cobalt or nickel and molybdenum or other salts in 
the solutions, one may vary the ratio of cobalt or nickel and molybdenum 
or other elements in the sulfide catalyst. 
The cobalt/molybdenum sulfide or other sulfide may then be separated from 
the solvent, dried, calcined and blended with a second component promoter 
such as potassium carbonate and agglomerating agents and/or pelleting 
lubricants, then pelleted and used as a catalyst in the process. It is 
preferred to protect such catalysts from oxygen from the time it is made 
until it is used. 
The alkali or alkaline earth second component may be added to the active 
catalytic elements prior to, during or after the formation of the sulfide 
by physical mixing or solution impregnation. The active metal sulfide may 
then be combined with binders such as bentonite clay and/or pelleting 
lubricants such as Sterotex.RTM. and formed into shapes for use as a 
catalyst. 
The finished catalyst may be used in a fixed bed, moving bed, fluid bed, 
ebullated bed or a graded fixed bed in which the concentration and/or 
activity in the catalyst varies from inlet to outlet in similar manner to 
known catalysts. The catalyst may be used in powder form or may be formed 
into shapes with or without a binder. 
Catalysts of the invention preferably contain less than 25 weight percent 
based on the total weight of carbon oxide hydrogenation active metals, of 
other carbon oxide hydrogenation active metals and more preferably less 
than 20 weight percent and most preferably less than 2 weight percent. The 
inventive catalyst may be essentially free of other carbon oxide 
hydrogenating components. By "essentially free" it is meant that the other 
carbon oxide hydrogenating components do not significantly alter the 
character or quantity of the alcohol fraction. For example, a significant 
change would be a 5 percent change in the amount of the alcohol fraction 
or a 5 percent change in the percentage of any alcohol in the alcohol 
fraction. 
Carbon oxide hydrogenating components present in thus limited quantities or 
excluded are preferably those that contain chromium, manganese, copper, 
zinc, ruthenium and rhodium. More preferably, in addition to the 
above-mentioned components, those that contain halogen such as iodine, 
rhenium, titanium, vanadium, cerium, thorium, uranium, iridium, palladium, 
platinum, silver and cadmium are excluded. 
Preferably, compounds acting as ligands are also absent. Exemplary ligands 
which may be limited or excluded include those that are disclosed in U.S. 
Pat. No. 4,405,815, which is incorporated herein by reference. These are 
generally polydentate ligands in which the donor atoms are phosphorous, 
arsenic, antimony or bismuth, though other monodentate and polydentate 
ligands may also be excluded. 
It may be advantageous to use conditions for the reaction which encourage 
low methanol to higher alcohol ratios in the product stream. Two 
alternative methods would be the aforementioned use of a sulfur-releasing 
compound in the feed or the addition of cobalt, nickel or iron to the 
catalyst. These two schemes generally do not work well when they are 
combined, so one normally uses one or the other. The conditions under 
which this reaction occurs are similar to those under which mixed alcohols 
may b formed directly from the H.sub.2 /CO synthesis gas. Accordingly, the 
alcohol conversion and the alcohol synthesis reactions take place 
simultaneously. 
In the normal operating ranges, the higher the pressure at a given 
temperature, the more selective the alcohols synthesis process will be to 
alcohols. The minimum contemplated pressure is about 500 psig (3.55 MPa). 
The preferred minimum is about 750 psig (5.27 MPa) with about 1000 psig 
(7.00 MPa) being a more preferred minimum. While about 1500 psig (10.4 
MPa) to about 4000 psig (27.7 MPa) is the most desirable range, higher 
pressures may be used and are limited primarily by the cost of high 
pressure vessels and compressors needed to carry out the higher pressure 
reactions. The typical maximum is about 10,000 psig (69.1 MPa) with about 
5000 psig (34.6 MPa) a more preferred maximum. A most preferred operating 
pressure is about 3000 psig (20.8 MPa). 
The minimum temperature used is governed by productivity considerations of 
the alcohols synthesis reaction and the fact that at temperatures below 
about 200.degree. C. volatile metal carbonyls may form. Alcohols may also 
condense at lower temperatures. Accordingly, the minimum temperature is 
generally around 200.degree. C. A preferred minimum temperature is 
240.degree. C. A maximum temperature is about 400.degree. C. Preferably, 
the maximum temperature is about 375.degree. C. or less, more preferably 
350.degree. C. or less and the most preferred range is from about 
240.degree. C. to about 325.degree. C. 
The H.sub.2 /CO gas hourly space velocity (GHSV) is a measure of volume of 
the hydrogen plus carbon monoxide gas at standard temperature and pressure 
passing a given volume of catalyst in an hour's time. This may range from 
about 100 to about 20,000 hr.sup.-1 and preferably from about 300 to about 
5000 hr.sup.-1. Selectivity to alcohols of the alcohols synthesis process 
generally increases as the space velocity increases. However, conversions 
of carbon monoxide and hydrogen decrease as space velocity increases and 
the selectivity to higher alcohols decreases as space velocity increases. 
Preferably, at least a portion of the unconverted hydrogen and carbon 
monoxide in the product gas from the reaction, more preferably after 
removal of product alcohols, water and carbon dioxide formed and even more 
preferably any hydrocarbons formed, may be recycled to the reaction. One 
may wish to isolate one or more of the alcohols and recycle that also. 
That is typically done in a separate step wherein the alcohol to be 
recycled is isolated from the balance of the alcohols. For purposes of 
this discussion, the amount of recycle is expressed as the recycle ratio 
which is the ratio of moles of gases in the recycle stream to the moles of 
gases in the fresh feed stream. A recycle ratio of zero is within the 
scope of the invention with at least some recycle preferred. A recycle 
ratio of at least about one is more preferred and at least about 3 is most 
preferred. 
The rate of alcohol fed to the process is generally expressed as liquid 
hourly space velocity (LHSV) which is defined as the volume of liquid 
alcohols feed at 0.degree. C. and 760 mm Hg pressure which is vaporized 
and passes over a catalyst bed in an hour's time ratioed to the volume of 
the catalyst bed. This feed rate may range from about 0.01 hr.sup.-1 to 
about 5 hr.sup.-1 and preferably from about 0.05 hr.sup.-1 to about 0.5 
hr.sup.-1. Preferably, there is a substantial excess of syngas to alcohol 
feed and generally, a ratio of at least 2 moles of hydrogen or carbon 
monoxide per mole of alcohol in the feed. 
The alcohol fraction formed boils in the motor gasoline range. The minimum 
boiling pure alcohol is methanol at 64.7.degree. C. ASTM D-439 calls for a 
225.degree. C. end-point for automotive gasoline. Accordingly, the alcohol 
may boil in a range from about 60.degree. C. to about 225.degree. C. when 
distilled by ASTM D-86. Other alcohols may boil outside this range but 
preferably do not. It is not necessary that the entire liquid product boil 
in this range, but it is preferred. It is not necessary that the alcohol 
fraction meet all the distillation specifications for motor gasoline; only 
that it boil within the broad range of motor gasolines. For example, it 
need not be within the 50 percent evaporated limits as set by ASTM D-439. 
Because two processes are taking place simultaneously, one must look at 
incremental yields to see the extent to which lower alcohols are being 
converted to higher alcohols. One process is a Fischer-Tropsch type 
process wherein H.sub.2 /CO are converted directly to mixed alcohols. And 
in fact, some of these alcohols after they are formed during the course of 
the process, are converted to higher alcohols within the reactor. The 
second process comprises the conversion of the lower alkanols which are 
fed to the process into higher alcohols. 
When the alcohol is easily differentiated from the products of the 
Fischer-Tropsch type alcohol synthesis, differentiation of the two 
processes is quite simple. For example, when the added alkanol is 
isopropanol, one need only analyze for homologues of isopropanol in the 
product to adequately define the yields. However, when the alcohol fed is 
methanol, for example, one must look at incremental yields, that is, look 
at the yield structure of the mixed alcohols formed without the addition 
of methanol and then look at the yield structure when methanol is added in 
addition to the H.sub.2 /CO feed. 
Using either of these schemes, preferably at least 25 percent of the 
alcohol added to the reaction is converted to higher homologues. 
Under preferred conditions, the amount of water formed is substantially 
less than the amount of alcohols formed. Typically, there is less than 20 
weight percent and preferably less than 10 weight percent water based on 
the quantity of alcohol. This water may be removed by known techniques if 
the alcohol fraction is to be used as a motor fuel additive. If the water 
content is about 5 weight percent or less based on alcohols, the water may 
advantageously be removed by absorption on molecular sieves. At higher 
water contents one may use a water-gas shift drying step as disclosed in 
British patent publication Nos. 2,076,015 and 2,076,423; and U.S. patent 
application, Attorney's docket No. 31,805-A, filed on or about Oct. 23, 
1984, which is a continuation-in-part of U.S. patent application Ser. No. 
508,625, filed June 28, 1983, now abandoned. These references are hereby 
incorporated herein by reference. 
The product mixture, as formed under preferred conditions, contains small 
portions of other oxygenated compounds besides alcohols. These other 
compounds may not be deleterious to use in the product, as is, in motor 
fuels. However, these other oxygenates, generally acetate esters, are 
formed in higher proportions when alcohols are added to the H.sub.2 /CO 
feed than when they are not. 
Preferably, the coproducts formed with the alcohol fraction are primarily 
gaseous products; that is, C.sub.1 -C.sub.4 hydrocarbons. Preferably, 
C.sub.5 + hydrocarbons are coproduced at less than about 20 percent 
CO.sub.2 -free carbon selectivity, more preferably at less than 10 percent 
and most preferably at less than 5 percent. Lower amounts of normally 
liquid hydrocarbons make the normally liquid alcohols easier to separate 
from by-products.

EXAMPLES 
Comparison A and Example 1 
Comparison A and Example 1 are conducted using a catalyst comprising 
molybdenum supported on carbon. 
Approximately a cubic foot of Witco MBV 4-6 mesh carbon in the form of 
3/16-inch (0.48 cm) extrudates is immersed for 10 minutes at 60.degree. 
C.-70.degree. C. in a solution containing 155.5 pounds of 22 percent 
ammonium sulfide, 26 pounds of ammonium heptamolybdate and 6.5 pounds of 
potassium carbonate. The extrudates are then removed and the excess liquor 
is drained therefrom. The extrudates are then calcined in nitrogen at 
300.degree. C. for four hours. These steps are repeated until the 
extrudates have absorbed 20 percent molybdenum and 5 percent potassium 
based on the total weight of the catalyst. After the last impregnation, 
the calcination temperature is raised to 500.degree. C. The catalyst is 
then passivated with 2 percent oxygen in nitrogen at a maximum temperature 
of 70.degree. C. 
The catalyst is placed in a 1/2-inch (1.27 cm) stainless steel tube. Total 
volume of the catalyst is 30 cm.sup.3. The weight of catalyst is 22 g. 
Premixed carbon monoxide and nitrogen from a cylinder is passed through a 
molecular sieve bed at ambient temperature to remove iron and other 
carbonyls. Hydrogen and hydrogen sulfide from cylinders is then mixed with 
the carbon monoxide and nitrogen and the mixture is compressed to the 
pressure stated. The nitrogen is added at about a 5 percent level to serve 
as an internal standard for analytical purposes. Methanol is added as 
stated using a high pressure liquid pump. 
The combined feed gas and methanol stream is then preheated and passed at 
the stated hourly space velocities through the fixed bed reactor which is 
maintained at the stated reaction temperatures by an electric furnace. 
The reactor product is passed through a pressure letdown valve into a 
vapor-liquid separator at room temperature. The product gases leaving the 
separator flow past the gas chromatograph sampling port, through a second 
pressure letdown valve into a dry ice cooled condenser. Liquid products 
from the vapor-liquid separator and the condenser are collected, weighed, 
sampled and analyzed. The data sets given represent the combined analyses 
of both of these samples. The results of the experiment are shown in Table 
I. 
TABLE I 
______________________________________ 
Comparison A 
Example 1 
______________________________________ 
Temperature (.degree.C.) 
260 260 
Pressure 
(psig) 2500 2500 
(MPa) 17.3 17.3 
H.sub.2 /CO GHSV (hr.sup.-1) 
1870 1870 
H.sub.2 /CO mole ratio 
1.12 1.12 
H.sub.2 S level (ppm)* 
20 20 
Methanol feed rate (g/hr) 
0 5.9 
Methanol (g/hr) 2.42 7.76 
Ethanol 0.81 1.57 
Propanols 0.15 0.27 
Butanols 0.016 0.023 
Pentanols -- -- 
Methyl Acetate 0.0433 0.211 
Ethyl Acetate 0.016 0.015 
______________________________________ 
*vol/vol based on H.sub.2 /CO 
The reaction conditions for Comparison A and Example 1 are identical except 
that methanol is not fed during Comparison A but is fed during Example 1. 
The addition of methanol results in an increase in the rate of production 
of higher alcohols. The large increase in the production of acetate esters 
suggests that the reaction may proceed through the formation of these 
acetates. 
Comparison B and Example 2 
The catalyst used in this example is a coprecipitated molybdenum cobalt 
sulfide. 
Ammonium tetrathiomolybdate (NH.sub.4).sub.2 MoS.sub.4 and cobalt acetate, 
in a mole ratio of molybdenum to cobalt of 2 to 1, are added to 30 percent 
acetic acid at 50.degree. C. The precipitate is filtered and dried under 
nitrogen at 120.degree. C. and then calcined for 1 hour at 500.degree. C. 
in a nitrogen atmosphere. The dry cake is then ground together with 
potassium carbonate, bentonite clay and Sterotex.RTM. to achieve a weight 
ratio of 66 weight percent (CoS/2MoS.sub.2), 10 weight percent K.sub.2 
CO.sub.3, 20 weight percent bentonite clay and 4 weight percent 
Sterotex.RTM.. This mixture is then pelleted at 30,000 psig and the 
pellets are stored under nitrogen until used. 
The reaction system for these examples is the same as that for Comparison A 
and Example 1. Total volume of catalyst is 30 cm.sup.3. The weight of 
catalyst is 32.7 g. The operating conditions and the results are shown in 
Table II. 
TABLE II 
______________________________________ 
Comparison B 
Example 2 
______________________________________ 
Temperature (.degree.C.) 
290 290 
Pressure 
(psig) 2000 2000 
(MPa) 13.8 13.8 
H.sub.2 /CO GHSV (hr.sup.-1) 
2000 2000 
H.sub.2 /CO mole ratio 
1.05 1.05 
H.sub.2 S level (ppm)* 
30 30 
Methanol feed rate (g/hr) 
0 7.0 
Methanol (g/hr) 1.96 2.73 
Ethanol 3.31 5.36 
Propanols 1.00 1.51 
Butanols 0.24 0.38 
Pentanols -- -- 
Methyl Acetate 0.070 0.148 
Ethyl Acetate 0.108 0.247 
______________________________________ 
*vol/vol based on H.sub.2 /CO 
The reaction conditions for Comparison B and Example 2 are identical except 
that methanol is not fed during Comparison B but is fed during Example 2. 
The addition of methanol results in an increase in the production of 
higher alcohols and again in the increase in production of acetate esters. 
Comparison C and Example 3 
In additional experiments ethanol is added to the H.sub.2 /CO feed. 
The catalysts in these two examples are the same as those used in Example 
2. The reaction is carried out in the same apparatus as Example 2. The 
reaction parameters and results are set out in Table III. 
TABLE III 
______________________________________ 
Comparison C 
Example 3 
______________________________________ 
Temperature (.degree.C.) 
289 289 
Pressure 
(psig) 2000 2000 
(MPa) 13.8 13.8 
H.sub.2 /CO GHSV (hr.sup.-1) 
3000 3000 
H.sub.2 /CO mole ratio 
1.08 1.08 
H.sub.2 S level (ppm)* 
90 90 
Ethanol feed rate (g/hr) 
0 3.32 
Methanol (g/hr) 1.80 1.76 
Ethanol 1.36 3.24 
Propanols 0.344 0.513 
Butanols 0.083 0.061 
Pentanols 0.011 0.000 
Methyl Acetate 0.046 0.055 
Ethyl Acetate 0.026 0.092 
______________________________________ 
*vol/vol based on H.sub.2 /CO 
It can be seen that the ethanol is converted to higher alcohols. The 
conversion is not as efficient as it is for methanol however. 
Comparison D and Example 4 
Using the same catalyst and reactor setup as Example 2, the reaction with 
ethanol is carried out again. The reaction conditions and results are as 
set out in Table IV. 
TABLE IV 
______________________________________ 
Comparison D 
Example 4 
______________________________________ 
Temperature (.degree.C.) 
270 270 
Pressure 
(psig) 3000 3000 
(MPa) 20.8 20.8 
H.sub.2 /CO GHSV (hr.sup.-1) 
2000 2000 
H.sub.2 /CO mole ratio 
1.05 1.05 
H.sub.2 S level (ppm)* 
30 25 
Ethanol feed rate (g/hr) 
0 2.21 
Methanol (g/hr) 1.078 1.198 
Ethanol 0.612 1.762 
Propanols 0.171 0.244 
Butanols 0.054 0.041 
Pentanols 0.006 0.000 
Methyl Acetate 0.064 0.081 
Ethyl Acetate 0.027 0.090 
______________________________________ 
*vol/vol based on H.sub.2 /CO 
Again, the ethanol is apparently converted to higher alcohols. 
Comparison E and Example 5 
The catalyst used in this example is an unsupported molybdenum disulfide 
catalyst comprising pelletized 66 percent MoS.sub.2 (High Surface Area 
Special MoS.sub.2 obtained from Climax Molybdenum), 20 percent bentonite 
clay, 10 percent K.sub.2 CO.sub.3, and 4 percent Sterotex.RTM.. 
In Comparison E and Example 5, the reactor consists of a jacketed stainless 
steel pipe packed with catalyst. The total volume of catalyst is about one 
cubic foot (0.028 m.sup.3). The reactor jacket carries a heat-transfer 
fluid to remove the heat of reaction. The carbon monoxide feed gas passes 
through a bed of molecular sieves at room temperature to remove iron and 
other carbonyls. The hydrogen and carbon monoxide feed gases are then 
mixed at the ratio stated with 300 ppm hydrogen sulfide. Nitrogen is added 
to the feed gas at two percent by volume as an internal standard and the 
mixture is compressed to the pressure stated. Methanol is added. The 
methanol and feed gas mixture is preheated to the stated reaction 
temperature and then passed through the fixed-bed reactor at the stated 
hourly space velocity. The reactor products pass through a water-cooled 
condenser into a high pressure vapor/liquid separator. The product liquids 
from the high pressure separator pass through a pressure letdown valve 
into a low pressure vapor/liquid separator. The product gases leaving the 
high pressure separator pass through a pressure letdown valve, are 
combined with the gases from the low pressure separator, and flow past a 
gas chromatograph sampling point. Liquid products from the low pressure 
separator are collected in a receiver where they may be sampled and 
analyzed. 
The reactor operating conditions for Comparison E and Example 5 are shown 
in Table V. 
TABLE V 
______________________________________ 
Comparison E 
Example 5 
______________________________________ 
Temperature (.degree.C.) 
233 233 
Pressure 
(psig) 1800 1800 
(MPa) 12.5 12.5 
H.sub.2 /CO GHSV (hr.sup.-1) 
896 888 
H.sub.2 /CO mole ratio 
1.04 1.05 
H.sub.2 S level (ppm)* 
300 300 
Methanol feed rate (g/hr) 
0 766.57 
Methanol (g/hr) 683.51 1050.29 
Ethanol 305.31 333.66 
Propanols 43.50 47.58 
Butanols 7.62 9.66 
Pentanols 0 0 
Methyl Acetate 24.31 51.39 
Ethyl Acetate 5.85 6.94 
______________________________________ 
*vol/vol based on H.sub.2 /CO 
The addition of methanol results in an increase in the production of higher 
alcohols and again in an increase in production of acetate esters. 
Although the invention has been described in considerable detail, it must 
be understood that such detail is for the purposes of illustration only 
and that many variations and modifications can be made by one skilled in 
the art without departing from the spirit and scope of the invention.