Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
L9g
Back~round of the Inventlon
Me~hyl mercaptan is a well known article of commerce, being used
as an intermediate for the manuEac~ure of a variety of agricultural chemicals,
and as a raw material for the manufacture of methionine, a widel~ used feed
supplement for poultry. The current preferred commercial method for manu-
acturing methyl mercaptan is by reaction oP methanol and hydrogen sulfide.
A variety of catalysts can be used such as thoria, zirconia, activated
aluminas, silica~aluminas, and alumina promoted with tungstates or moly-
bdates (U.5. Patent 2,820,062) or wlth heteropoly acids or their salts
~U.S. Patent 3,035,097?. These processes as practiced commercially are
highly efficient and provide methyl mercaptan in high yield and purity.
Nevertheless, further economy can be achieved by the use of the
more basic raw materials carbon monoxide or carbon dlo~lde ln place of
methanol. Methyl mercaptan can be prepared from carbon oxldes accordlng
to the following equations:
( ) 2 2 ~ 3 2
(2) C02 + H2S + 3H2~ CH3SH + 2H20
U.S. Patent No. 33070,632 to Olin et al, that issued December 25,
1962, discloses the prior art process associated with equations (1) and
(2) above.
The above prior art method has a number of shortcomings from a
commercial viewpoint. The yields are rather low. The most favourable
yield for methyl mercaptan is in Example 2 of the above patent and ~s
23.2%. The two phase cataly~t system is a comple~ system involving a
large amount of powdered sulfactive hydrogenation catalyst suspended in a
large volume of a liquid organic amine, relative to the amount of reactants
employed. The preferred reaction conditions disclosed in the above patent
are inherently expensive from a conmlerclal viewpoint as they involve operat-
ing at high pressureswlthin the 1200 to 2000 psig. range over long reaction
t:Lmes of 3 to 6 hours.
In addition, the amLne co-catalyst of the prior art method produces
hydrosulfide salts at the reactlon conditions and these salts are unstable
at standard atmospheric conditions, whereby highly toxic hydrogen sulfide
gas is released. The yield in the above patent is particularly low with
respect to utili~ing carbon dio~ide as the raw materlal, as shown in the
aforementioned equation (2~. Example 1 of the above patent shnws carbon
monoxide produces a yield of 17.7%. Less than 5% conversion is obtained
with carbon dioxide.
The improved process of this invention overcomes these shortcomings
and provides a practical and economical process for the produc~ion of methyl
mercaptan from carbon oxides.
; The prDcess of this invention involves a single-phase solid catalyst
composition that is considerably more active in promoting the above reactions
1 and 2 to provide vastIy improved yields over the aforementioned U.S. patent.
The process of this invention provides a continuous process requiring
relatlvely short reaction times at mild conditions~of temperature and
pressure, thereby making the process to be of practical application.
Summary of the Invention
The process of this invention is defined as an lmprovement in a
process for the manufacture o methyl mercaptan which includes feeding
a carbon oxide, hydrogen sulfide or elemental sulfur, and hydrogen reactants
to a reactor and subJecting the reactants to reaction conditions including
h$gh temperature and pressure in the presence oE a hydrogenation catalyst
to provide methyl mercaptan; the improvement which comprises, utilizing a
single-phase, solid catal~st prepared by ~he process which comprises:
-- 2 --
~,
g
A. mlxing:
~1~ an oxLde, sul1de, hydroxide or salt of a metal or metals
selected rom the group conslsting of lron~ nlckel,
chromium, cobalt and molybdenllm, wlth
(2~ an effectlve amount of an alkali metal inorg~nic base
selected from the group of alkali metal bases consisting
of oxide, hydroxlde, sulfide or salt to provide an admixture;
and then
B. at least partially sulfldlng the admixture oi A by heating
the admlxture in the presence of hydrogen sulfide or ele~ental
sulfur; with the proviso that step B is optlonal when a metal
sulfide is used in both steps A(l~ and A~2);
to prov~de enhanced conversions with lower reaction times at lower tempera-
ture and pressure conditions, wlthout the formation of substantial un-
desirable by-products.
It ls preferred that the metal oxide, stslflde, hydroxide or salt
in step A(13 be on a support, with activated alumlna be-Lng the most pre-
ferred support.
Nickel is the preferred metal with nickel oxide being preferred as
the presulfide form.
The process works well with either carbon monoxide or carbon dioxlde,
but carbon monoxide is preferred.
In step ~(2), the inorganic base can be an o~ide, hydroxide~ sulfide,
or salt of potassium, rubldlum, or cesium, wlth cesium belng the most
preferable.
It i9 preferred that the reactants carbon oxide, hydrogen sulflde
and hydrogen are ed to the reactor in a molar ratio within the range of
about 1/3/2 to about 1/8/8 with respect to one ano~her.
-- 3 --
,. ~
^?'~
~' :
99
The hydrogen sulfide reactant can be preliared in situ within the
reactor by feeding elemental sulfur to the reactor, i.n which case the molar
ratlo of carbon oxide, elemental sulfur and hydrogen with respect to one
another charged to the reactor is wlthin the range of about 1/3/3 to about
1/8/10.
'l`he preferred temperature within the reactor ls within the range
of about 250 C to about 350 C; ~hereas, the preferred pressure is within
the range of about 600 to about 1000 psig.
It is preferred to operate the process at conditions to provide a
space velocity within the range of about 5 to about 200 volumes of carbon
oxide per volume of catalyst per hour~
It is desirable to preheat the reactants prior to feedlng to the
reactor, with a preheating temperature within ~he range o:E about 180 C to
about 300 C.
The above catalyst can al50 be defined as a composition after ~he
sulfiding step of B above. The catalyst composition is defined as a single-
phase, solid catalyst composition whlch comprises:
(a) a metalllc sulfide or mixture of metallic sulfides selected
from the group of sulfides consisting of iron, nickel5
chromium, cobalt and molybdenum sulfides, in admixture with
(b) an alkall metal sulfide and/or hydrosulfide,
to provide enhanced converslons with lower reaction times at lower tempera-
ture and pressure conditions, without the formation of substantlal
undeslrable by-products.
D~ tion of the Preferred Embodiments
The ca~alyst consists of a conventional hydrogenation catalyst
treated with an inorganic base and sulfided with hydrogen sulfide at
elevated temper:tures.
-- 4 --
.,
..
.
4c~g
The inorganic base may be any alkali metal oxide, sulfide, hydroxide
or salt, and is preferably the oxide, sulfide, hydroxide or salt of potas-
sium, rubidium or cesium. It ls understood that on treatment with H2S these
bases are at least partially conver~ed to the hydrosulfides and/or sulfides.
The conventlonal hydrogenation catalysts used may conslst of iron,
nickel, chromium, cobalt or molybdenum, singly or in combination as their
oxides, sulfldes, hydroxides or salts alone or on a suitable support such
as alumina, silica, kieselguhr, carbon, clays or refractory materials. The
preferred hydrogenating me~al i9 nlckel. The hydrogenating metals are at
least partlally converted to the sulfides on treatment with H2S. The pre-
ferred support is an activated alumina.
The most preferred catalyst composition contains about 5% by weight
cesium sulfide and 13~ by weight nlckel sulfide supported on activated
alumina. In a typical preparation 950 grams of a co~mercial pel:Letized
hydrogenation catalyst containlng 11% nickel oxide on activated alumina
(Harshaw* N~-0301 T) i9 predried at 150C and impregnated with a solution
containing 50 grams of cesium hydroxide in 250 cc. of water. The solution
is added slowly with thorough mlxing and the wet catalyst is dried overnight
in an oven at 150 C.
The dried catalyst is charged into the process reactor and sulfided
by passing hydrogen sulfide gas over it at about 370C and atmospheric
pressure for several hours (e.g., 6-8 hours) until water of reac~ion is no
longer preserlt in the effluent gas stream. The catalyst is now ready to
use in the proces~.
The process is preferably operated in a continuous fashion by pre-
heating and premixing the reactant gases carbon monoxide or carbon dioxide,
hydrogen sulfide, and hydrogen, and passing the mixture over the catalyst
bed under appropriate conditions ~or reaction ~o occur. 1~e ratio o
* Trade Mark - 5 -
~ ~ .
reactants ~o be used is based on the stolchio~etry of equations (1) and (2).
Preferably the carbon o~ide will be reacted with a molar excess of hydrogen
sulfide and a molar excess of hydrogen. Most preferably, molar raeios of
COl 2/H2SIH2 between 1/3/2 and 1/8/8 are used. The gases are preheated to
about 180-300C, mixed and passed through the catalyst bed to effect reac-
tion.
A wide range of reactionconditions may be used to obtain conversion
to methyl mercaptan. In general the production of methyl mercaptan is
favoured by higher pressuresup to about 600-lOOO pslg., catalyst bed temp-
eratures in the range 250-350 C, and space velocities ranging from abou~
5 to 200 liters of carbon oxide per liter of catalyst per hour. Methyl
mer aptan formation is also favoured by longer catalyst contact times, i.e.
lower space velocities, but tn commercial practice where high production
rates are desired, this process can be operated at higher sp~ce velocities
in the range of 60-200 liters of carbon oxide per liter of catalyst per
hour with relatively high conversions of carbon oxide to methyl mercaptan
per pass. The unconverted reactants can be separated by distillation from
the products and recycled in a commercial operation to obtain maximum
economy in raw materials.
Carbon monoxide is more reactive than the dioxide in this process
and ls the preferred raw material for operation with high conversions at
the higher space velocities. Elemental sulfur may be substituted for the
hydrogen sulfide in the proce3s, since the hydrogen present in the feed
mixture will convert the sulfur to hydrogen sulfide in situ at the process
conditions. Correspondingly higher ratios of hydrogen must of course be
used when elemental sulfur is substituted for hydrogen sulfide, the pre-
ferred molar ratlos of`COl 2/S/H2/ ranging from about 1/313 to about 1/8tlO.
The equations for~the reactions with elemental sulEur are as follows:
- 6 -
~.,g~.,
Z
9~
(3) C0 S 3a2 > 3 2
(4) C~2 ~ S + 4~2 -- iCH3SH ~ 2H20.
Carbon mono~ide-hydrogen mixtures can be inexpensively produced from
methane and steam by the well known l'synthesis gas" process,
( ) 4 2 ) C0 ~ 3H2.
By adding hydrogen sulfide or elemental sulfur to "synthesls gas" a suitable
low cos~ reactant mlxture is obtained to produce methyl mercaptan by this
process.
The improved process for the production of methyl mercaptan is
illustrated by the following examples.
~xample 1
A series of inorganic (alkali and alkaline earth hydroxides and
salts) basic promoters are evaluated at 5~ by weight Otl a comme~cial 11%
nickel oxide on al.umina catalyst tHarshaw* Ni-0301T) using a fixed bed~
tubular, continuous reactor The reactants are carbon mono~lde, hydrogen
sulfide and hydrogen. The initial nlekel oxide - alumina catalyst has a
surface area of 64 9q . meters per gra~, a pore volu~e of 0.32 cc per gram,
average bulk density of 70 lbs. per cu. ft., table~ed in 1/8 inch tablets.
The reactants are mlxed ~st prlor to being passed downward through the
vertically mounted reactor, with no preheating. Conversions to methyl
mercaptan are relati~ely low due to lack of preheating and the low pressure
employed (175 psig), but the data serve to compare the effectiveness of
the vari.ous basic promoters. Carbon dloxide is a major by-product at the
low pressure. The pressure ls controlled by an automatic back-pressure
regulator, and the crude product stream is passed as a vapor through heated
lines at atmospheric pressure into ~he gas sampling device of a gas chroma~
tograph for analyses.. The single-pass conversions and yields of carbon
monoxide to me~hyl mercaptan (M~l) are calculated from the gas chromatographic
-- 7 --
9~
analyses.
The yield flgures take into account vnly ~he ~mreacted carbon
monoxide remainlng in the crude product after a sin~le-pas~ through the
reactor and do not include by products such as carbon dioxlde, carbonyl
sulfide, and carbon disulflde which can ln fact be recycled to produce
additional M~, with high ultimate ylelds.
The reaction conditions, conversions and yie].ds to ~ are shown in
Table 1 belo~. ~11 runs are of at least 15 hours duration. All catalysts
are presulfided by passing hydrogen sulflde gas over them at about 370 C
and atmospher:Lc pressure for about si~ hours.
o
-- 8 --
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~ ~ c~ ~t ~ ~ ~ ~ ~`~ ~ ~ J ~ J ~ r~ h
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___ _ _ _ _ _ _ _ __ _ ___ ':J
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~ ~ ~ oo co 00 ~0 oO CO o~ a
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~ ~ r-l r-l r~l r-l r~l r~l r-l ~1 r-l r~ ~1 r~l ~ ~ h
_ _ __ _ _ _ _ __ ___ .,u
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r~ r~ ,~ r- ,~ r~ ,-1 r~ rl r-l r~ ,1 . ~ r~
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F~. 1~r~ 1~ 1~ 0~ 0~ oO ~ OD OD CO CO ~ 0~ rt~
~8 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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o, ~ ~ u~ ~ ~ ~ ~ In ~ ~
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u æ ~ ~ ~. ~ o~ o~ o~ ~ o~ ~ c
o~ o~ o~ P~ ~ :~ ~o, P~ C~
~e ~ I o $ ~, æ E~ ~ ~ ~ ~ ~ o
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_ __~ _Z Z _ _ _ ~ P~ ~ p:; ~ ~ C~
_ 9 _ _ __ _ _
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Following up on the resnlts of Example l and using the same operat-
ing procedure and general reaction condit.ions (175 psig.), various levels
of cesium hydroxide pro~oter on the 11% nlckel oxide on alumina catalyst
(~larshaw* Nl-0301T) are lnvestigated. All catalysts are presulfided. All
experiments are carried out at a space velocity ~f 5 liters C0/liter
catalyst/hour, a C0/H2S/H2 molar feed ratio of l/8/4~ and 175 psig. pressure.
The resuLts are given in Table 2 below and show the 5% cesium hydroxide on
NiO/A1203 catalyst ~o give optimu~ convarsion to MM. The conversions and
yields for this and succeeding Exan~ples are calculated in the same manner
as in Example 1.
Table 2
_ _ ~
Ca~alyst Catal~st Avg. % Avg. %
Temp. C Conversion Yield
CO ~ MM CO~
1% CsOH on NiO/A12O3 288 31.0 .34.2
2,5% CsOH on NiO/A1203 286 37.8 40.4
5% CsOH on NiO/Al2O3 290 46.9 47.6
10% CsOH on NiO/A12O3 290 39,8 42.5
" .~02 ~3.7 45.2
313 44.5 45.7
, 318 45.4 47.3
_ _331 44.6 45.4
-----
Exa~ple 3
Various 5% alkali hydroxide-promo~ed metal oxide hydrogenation
catalysts are eva]uated using the same operating procedure and reactlon
~ 10 -
4~3
conditions (175 pslg) as in Example 2. All catalysts are presulfided.
The results are s~lown in Table 3 below.
TABLE 3
_~ _ , _ _ . __ ~
Catalyst Ca~alyst Avg. ~ Avg.
Bed Conversion Yleld
Temp. C CO ~MM CO -~MM
__ _.~
5% KOH on Co-Mo/A12O3 (1) 289 15 18
5~ CSOH on CoO/A1203 (2) 288 17 l9
5% KOH on NlO/Kieselguhr t3) 283 3 11
5% KOH on A12O3 (4) 282 16 24
5% CSOH on Ni-Co-Mo~Al~D3 ~5) 288 17 17
(1) Co-Mo/Al2O3: HDS-16A(American Cyanamid)
(2) CoO/A1~03: G-67~Girdler)
(3) NiO/Kieselguhr: HSC 102~Houdry)
(4) Al203: H-151(Alcoa)
(5) Ni-Co-Mo/Al203: G76(Girdler)
Exam~ ~,
High collversions and yields of carbon monoxide ~o methyl mercaptan
are obtained by preheating the reactants and carrylng, nut the reaction at
higher pressures above 400 psig. At the higher pressures the CO i5 con-
verted to more MM at the expense of by-product C02. It is believed that
the CO2 arises from the reaction of starting material CO wlth reaction by-
product H20 according to the well known reactlon,
CO ~ H20 ~ C2 ~ ~2. ~le C02
apparently reacts slowly with H2S and H2 (according to equation 2) at low
pressures, but ~wch more rapidly at higher pressures. Pressures above
about 700 psig., however, are not necessary to obtain high conversions to
MM as shDwn by ~he results in Table 4 below, usin~ 5% KOH on NiO/~1203 and
5% CsOH on NiO/A1203 catalysts prepared from Harshaw's Ni-0301T NiO/A1203
- 11 - I
V49~
and presulfided at 370 C and atmospherlc pressure for about 9iX hours with
hydrogen sulflde, prlor to use.
__, ___ _ __ _ _ __ _ ____._ .
~ ~ t~ ~ tS~ _ r~ t`l _ ~ ~ ;l ,~,
r~ 'I` ti ~t; ~ ~~1 ~ ~C) I~ ~) t~l ~4 O
~r I In ~D ~) U~~g u~ ~ 1~ CCl ~ ~0 Cl\
~ ~__ _ _. _ _ _ _ _ _ __. ____
.~
¦` ~ ~o tX~ o oI~ I_ r-~ ~D . ~1 t~l
~1) t~ t~ ~ t~l t`i t`l ~:) t' ~ ~ tS~ ~D O
~0 ~ ~ ~ U~ ~ U~ ~V ~ t~ U~ t~ t~
o~C '-~10 co o~ a~ ~ ~ ~ -co ~ __.
m ~ .~ x) co .~ 00 .~ .~ .~ .~` 00 00
o ~
~ ~ ~ r--i 1--l r~/ r I r-l r-l r-~ ~--1 r-l r-l r-l r-l
1_1 ___ __ _- _ _ _ __ _ _ ._ _ __
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t/~ t~ Ir~ ~ U~ U~ U~ U~ In U~ ~r~ ~ u~
0~ .
~oC~ ___ _ _ _ ___ _ _ _ __
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V E~ I~ t,o c~ ~ tJ~ tJ~ tJ~ tX) tJ~ tJ~ Cl~ t~
~1tL) ~ ~`I t~l t`l t~l t~l C`J t~l t~l t~l (~ ~ ~ t`l
~" _ . __ _ _ _ ._ _ __ __ _ ~ __
V ~ t~
~d r t~ O O O O O O O O O O O tf O
tU O O O O O O O O O O O O O
~3v~ o~ _1 .-1 _1 _ ,~ ~ _1 __ __~ __ __
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tn . o o o o o o o o o o o o ~q o
o o o o ~ o o o O o c~ O
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- 12 - .
.... --..
.
.
~ le 5
As the C0 space veloclty is increased, the conversion to M~I
decreases and the amount of by-product C02 incrcase3. I~ is found
beneficlal for high conversions a~ h1gher space velocities to use less
of a molar e~cess of H2S and H2 over CO in the feed mixture and sligh~ly
higher catalyst temperatures. Fhe data in Table 5 show that fairly
high conversions of C0 to M~I are obtained at commercially practlcal
space velocities in the range of 60 to 180 liters of C0 per liter of
catalyst per hour. The maJor by-produc~ at the higher space velocities
ls C02, whlch (as sbown ln the followlng Example 6) can be recycled to
produce addltional M~I, or can be reconverted to C0 by a well known reaction
with methane, 2 ~ CH4 ~ 2C0 -t 2H2, or other means, to provlde
hlgh ultimate yields of MM.
The catalyst used ln the~e experiments is S~ by welght CsOH lm-
pregnated on a commercial ll,u' NiO/A1203 (Harshaw* Nl-0301T) catalyst and
presulfided with hydrogen sulfide as described previously.
TABLE 5
C0 Space ColH2s/H Cata]yst Pressure Avg. ~
velocity molar ra2cio Temp., C psig. Conversion
C0 ~ MM
. __ _~
l/8/4 275 700 ) 89
1/8/4 ~75 70~ ~ 54
1/6/2 275 700 61
1/4/2 275 700 57
1/3/2 275 700 54
120 1/6/2 299 700 53
180 1/8/3 316 700 49
. . .. .. ~ . .
Example 6
Carbon dioxlde, hydrogen sulfide and hydrogen streams are separate-
ly preheated at 150-l90 C, mixed, and passed continuously into a horizon-
tal reactor contai.ning a 5~ by weight cesium hydroxide-promoted NiO/Al203
catalyst ~Harshaw's Ni-0301T) at 260-295 C. The pressure in the reactor
- 13 -
. ~
is maintained at 700 psig~ by means of a back pressure regulator valve.
The molar ratio of C02/H2SIH2 ~n the feed mixture ls 1/8/4. The crude
product mlxture is passed at atmospheric pressure by means of heated 316
sta:Lnless steel tubing to the heated gas sampling device of a gas chroma-
tograph for analysis. Conversions and yields of the C02 to MM are cal-
culated from the GC analysis.
The results, summarized in Table 6 below, show that C02 is like-
wise converted to M~l, bu~ that it is somewhat slower to react and g~ves
lower converslons to ~ per pass than carbon monoxide does at the same
reaction condi~lons.
.
~04~D
,~ .,~1 .,, ~ ,~,
o~ o~ ~:
~ _ ~
~ ~ ~ ~ U~ .
~; R o~`l _~_ O
~ 0000 ~ :
~q ~ o O ~ O ~J
O~ _ O
~r~ ~1
~ td~ ~--o~ ~ ,~
~ ~ ~ ~ ~ V
o~ , ~'o~ 0~ ' :
~ ~ r~
~ _~ ~
O ~ o o o ~ ;~
:~ _ ~ ~ ~
___ __ D u
~d~ U)U~ o ~V
O~p ~ ~_
The above Examples 1-6 show ~he ability of the process oE this
invention to be used in a continuous manner at commercially feaslble
reaction condltions to produce methyl mercaptan from carbon monoxide
- 15 -
''' , : ~
499
and carbon dioxide with high convcrsions and yields.
When the preferred carbon monoxide is used as the startlng
materiall gas chromatographic analyses of ~he crude product streams show
carbon dloxide to be the maJor by-product, with small amounts of carbonyl
sulflde and dimethyl sulfide and traces of methane also detected. Metharle
formation is minimlzed by maintainlng the reaction temperature below
about 300C. The remaining by-products are easily separated by distilla-
tion In no case is methanol detectecl to be present in the crude product
stream, indicating that it is not an intermediate in this process. The
reaction sequence by which carbon monoxide is converted to ~ thus is as
follows:
(6) C0 ~ H2S ~ ?COS ~ H2
(7) COS + 3H2 3 3 2
Reactions 6 and 7 proceed readlly with the preferred catalystand ~nditions
of this process, whereas C0 and H2 do not react to produce methanol at
these conditions~
The proportion oP hydrogenation catalyst used in admixture with the
alkali metal promoter as described herein preferably ranges from about 70
to 95 percent, based on the weight of the admlxture, while the proportion
of the alkali metal promoter ranges from about 30 to about 5 percent.
This admixture is preferably carried by an alumina support wherein the
alumina corlsists of about 10 to about 90 percent of the total welght of
catalyst system i.e., hydrogenation catalyst, alkali metal promo~er and
support.
In another embodiment oE thls invention, an alkali promoted
zlnc chromite on an alumlna support offers certaln advantages over the
prevlously described catalyst of this inventlon. The following is set
forth to demonstrate this embodiment.
~ ,
~,
.~
V~9
A catalys~ i~ prepared by 1~ impregna~ing Harshaw~s ZN-0601
zlnc chromite - ZntGrO2)2~ ZnO ~ Cr203 - on alumina catalyst with
cesium hydroxLde so that ~he final catalyst is 10% by weight cesium
hydroxide, and 2) sulfiding the catalyst by passing hydrogen sulfide
gas over it as previously described hereinbefore. m e Hawshaw* ~N-0601
ca~alyst consists of 38% zinc oxide (YnO) and 25% chromium oxide (Cr203)
on activated alumina (Al~03). It has an average bulk density of 97 lbs/
cu. ft , a surface area of 56 M /G, and a pore volume of 0.18 CC/G.
The zinc containing catalyst~ prepared as shown above was used
to prepare methyl mercaptan as shown in the followlng example
CO ~ S ~ 3H2 ~ ~ CH3SH + H20
Molten sulfur is vaporized in a preheater and mixes with carbon
monoxlde and hydrogen to provlde a gaseous feed mixttlre containing carbon
monoxide, sulfur9 and hydrogen :Ln a molar ra~lo of 1¦6/4. The mixture
is passed continuously over the above described zinc catalyst at a
carbon monoxlde gaseous space velocity of 80 HR -i*. The pressure in
the reactor is maintained at 250 psig., and the catalyst bed temperature
is maintained at 665 degrees F. (395.6 degrees C).
Gas chromatographlc analysis of the product stream exiting from
the reactor shows a high hydrogen sulfide content, and a 27.6% conversion
of the carbon monoxide to methyl mercaptan. All the sulfur is consumed
in one pass through the reactor. Recycling of ~he hydrogen sulfide
eormed in the flrst pass over the catalyst will produce addltional methyl
mercaptan.
* Space velocity: Liters of carbon oxide per liter of catalyst per
hour at standard temperature and pressure.
17 -
:. i' .
