Note: Descriptions are shown in the official language in which they were submitted.
~3~2
HYDROALKYLATION USING MULTI METALLIC Z~OLIT~ CATALYST
The invention relates to a hydroalkylation process, a composition
useful as a catalyst in said process and a method for producing said composi-
tion.
Prior art catalysts in the field of hydroalkylation processes suf-
fered from several drawbacks. These deficiencies of the prior art catalysts
for the hydroalkylation reaction included: (1) The use of support materials
for certain catalysts which are not able to withstand the temperatures employed
in a typical air burn-off regeneration operation. Such regeneration operations
are commonplace in the cataly~ic art for hydrocarbon conversions of various
types and it is highly desirable that the catalyst for the hydroalkylation pro-
cess be stable to such typically employed regeneration conditions. (2) In the
hydroalkylation of aromatic hydrocarbons to cycloalkyl aromatic hydrocarbons,
a problem in terms of selectivity to the deslred product is often evident. For
example, in the conversion of benæene to cyclohexylbenzene, by-products such
as cyclohexane and methylcyclopentylbenzene as well as dicyclohexylbenzene and
othPr heavier molecules can often be produced in such quantities that the pro-
cess can become uneconomical. Thus, a more selective hydroalkylation catalyst
is desired with little or no decrease in catalyst activity. It is~ however,
recognized that a decrease ln catalyst actlvity can often be tolerated if there
is a concomitant increase ln selectivity to ~he desired product. (3) A number
of the catalysts of the prior art for the hydroalkylation reaction are prepared
by very complex and time consuming processes. For example, starting with a
powdered crystalline zeolite support, said support is cation exchanged, washed
and then incorporated into a matrix of another mater~al such as sillca-alumina.
Thi~ combination i8 calcined, cooled, and impregnated with certain metal salts.
Finally the composite i~ extruded into pellets and the like. Thus, it is de-
sirable that a more simplfied and less expensive process for making active
and selective catalysts be found. (4) Certain catalysts of the prior art for
the hydroalkylation reaction were of fixed acidity because of the type o~ sup-
por~ material utilized. This left little variation that could be made in this
-
*~
important property of the hydroalkylation catalyst. It is therefore desirable
that catalysts be developed which are varied easily in their acidity charac-
teristics.
It is an object of the present invention to hydroalkylate aromatic
compounds.
Another ob~ect of the present invention is to provide a method for
producing a composition useful as a hydroalkylation catalyst.
Another ob~ect of the invention is a composition useful as a catalyst
in hydroalkylation reactions which i9 regenerated by air burn-off.
Another ob;ect of the invention is a composition useful as a catalyst
in hydroalkylation reactions which is More active and more selective than prior
art catalysts.
Another object of the invention is a composition useful as a catalyst
in hydroalkylation reactions which is simpler and less expens~ve to produce as
compared to prior art catalysts.
Still another object of the invention is a composition useful as a
catalyst in hydroalkylation reac$ions in which the acidity of the catalyst can
be adjusted.
According to the invention an aromatic hydrocarbon is contacted
under hydroalkylation condi~ions and in the presence of hydrogen with a composi-~ tion comprising at least one pla~inum compound æupported on a nickel and
;~ rare earth-treated crystalline zeolite support which is calcined to produce
- ~ an acidic support before or after impregnating the platinum compound on the
: ~ ~
support wherein said composition further comprises a halide content sufficient
to promote the selectivity-~of the composition ~o produce a desired cycloalkyl
aromatic hydrocarbon. Such a composi~ion when used as a catalyst is regen-
erated by air burn-off and i~ a highly active and selective catalyst.
-~; Further according to the invention an aromatic hydrocarbon is con-
taFted under hydroalkylation conditions and in the presence of hydrogen with
a composition comprising at least one platinum compound supported on a nickel
; '
~ 2
73~
and rare earth-treated crystalline zeolite support which i8 calcined to pro-
duce an acidic support before or after impregnating the platinum compound on
the support wherein said composition further comprises a halide content rang-
ing from about 0.1 to about 100 milligrams of elemental halogen per gram of
the composition,
Further according to the invention a composition comprises at least
one platinum compound supported on a calcined, acidic, nickel and rare earth-
treated crystalline zeolite which additionally has a halide content ranging
from about 0.1 to about lO0 milligrams of elemental halogen per gram of the
composition.
Further according to the invention the above composition is prepared
by contacting a crystalline zeolite with an aqueous cation exchange solution
comprising rare earth, nickel and ammonium compounds, removing the zeolite
from said solution and washing said zeolite with water to remove excess ions;
calcining said cation exchange æeolite; cooling said calcined zeolite; impreg-
nating said catlon exchange zeolite before or after said calcination step with
a solution comprising at least one platinum compound in a suitable solvent and
removing said solvent by evaporation and subsequently contacting said platinum
impregnated and calcined zeolite with a halogen containing compound in an
amount ranging from about 0.1 to about 100 milligrams of elemental halogen
per gram of the composition.
Further according to the invention a composition comprises at least
one platinum compound supported on a calcined, acidic, nickel and rare earth-
treated crystalline zeolite which additionally has a halide content sufficient
' ,~
to promote the selectivity of the composition to produce a deæired cycloalkyl
aromatic hydrocarbon when used to contact an aromatic hydrocarbon in a hydro-
alkylation reaction.~
Further according to the lnvention the above composition is prepared
by ontacting a crystalline zeolite with an aqueous cation exchange solution
comprlsing rare earth, nickel and ammonium compounds; removing the zeolite
from said solution and washing said zeolite with water to remove excess ions;
, . . . .
, . . . . . .
73~L~
calcining said cation exchanged zeolite; cooling said calcined zeo~ite; im-
pregnating said cation exchanged zeolite before or after said calcination s~ep
with a solution comprising at least one platinum compound in a suitable sol-
vent and removing said solvent by evaporation and subsequently contacting said
platinum impregnated and calcined zeolite with a halogen-containing compound
in an amount sufficient to promote the selectivity of said composition to
produce a desired cycloalkyl aromatic hydrocarbon when said composition is
used to contact an aromatic hydrocarbon in a hydroalkylation process. The
acidity of the above composition is easily adjusted by varying the conditions
under which the cation exchange step i8 carried out, such as, for example,
adjusting the concentration of an ammonium compound in the cation exchange
solution.
Detailed Descri~tion of the Invention
The compositlon of the instant invention can be briefly described as
a platinum impregnated crystalline zeolite which has been cation exchanged
with rare earth, nickel and ammonium compounds, calcined either before or
after the platinum impregnation step and followed by contacting the platinum
impregnated zeolite with a halogen-containing compound. It was discovered
that the presence of the hallde in a relatively small amount as compared to
the total weight of the catalyst significantly increases the selectivity of
the catalyst to produce a cycloalkyl aromatic hydrocarbon when the catalyst is
used to hydroalkylate aromatic hydrocarbons as compared ~o the same catalyst
without the halide component. Generally the presence of the halide component
reduces the activity of the catalyst somewhat, but generally the increase in
selectivity more than compensates for the reduction in activity. Although not
absolutely necessary, it is preferred that the above catalyst be treated with
hydrogen prior to introduction of the aromatic hydrocarbon feed in the hydro-
alkylation process becau~e of improved results.
The compositions of the instant invention are useful as catalysts
and to some extent solve or obviate each of the above-mentioned deficiencies
of the prior art cataly0t. For example, the supports utilized or the compo-
sitions of the instant invention are stable to regeneration conditions utilized
73~
under typical alr burn-off operations, they appear to operate at highe~
levels of productivity in that they show a higher degree of activi~y and aelec-
tivity than certain of the prior art catalysts; the process of making the co~-
positions of the instant invention is simple and straightforward and the com-
positions thus obtained should be less expensive than those of the prior art
which utilize very complex steps in their preparation; and the compositions
of the instant invention can be made with a high degree of flexibility in the
degree of acidity simply by ad~usting the cation exchange conditions on the
crystalline zeolite support utilized for the compositions of this invention.
The support material for the composition employed in the instant
invention is a crystalline zeolite which has been treated under cation ex-
change conditions with rare earth, nickel and ammonium compounds such that
the cation metal content of the support is partially exchanged. Generally the
- cationic metal is an alkali metal which is sufficiently removed by cation ex-
change such that the remaining alkali metal content after the cation exchange
step ranges from about 0.01 to about 2 percent by weight; however, the runs
carried out in accordance with the invention and reported herein indicate that
good results can be obtained when the alkali metal content of the cation ex-
changed zeolite ranges from about Ool to about 1 percent by weight. Some of
the more comm~nly employed crystalline zeolites which are suitable for use in
accordance with the present invention are the Type X or Type Y crystalline
zeolites which are sometimes called molecular sieves because of their essen-
tially uniform pore diameters~ Some sui~able Type Y synthetic crystalline
zeolites are described for example in U. S. Pa~ent 3,130,007 and some suitable
Type X zeolites are described in U.S. Patent 2,882,2440 Such materials are
~
presently commercially available as for example zeolites SK-40 (Type Y) and
13X (Type X) from the Linde Di~islon of Union Carbide Corporation~ ~ew York,
New Y~rk.
The alkali metal form of the crystalline zeolites usually comprlses
sodium as the alkali metal and said zeolites are treated under cation exchange
conditions with a mixture of rare earth9 nickel and ammonium compounds in
:
,
,
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accordance with the present inventlon in order to provide a suitable support
material for use in the preparation of the compositions of the invention.
It is contemplated that any of the readily available rare earth
metal compounds may be employed in the cation exchange solution. Generally,
the compounds used are those in which the rare earth metal-containing ion is
present in the cationic state. Representative rare earth metal compounds in-
clude nitrates, bromides, acetates, chlorides, iodides, sulfates and mixtures
thereof of one or more of the rare earth metals including cerium, lanthanum,
praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium,
holmium, erbium, thulium, ytterbium, and lutetium. Compounds of the rare
earths nam4d above may be employed singly, however, i~ i5 often convenient to
employ rommercially available mixtures of the rare earth-. For example, mix-
tures of rare earth metal compounds such as the chlorides of lanthanum, cerium,
praseodymium, neodymium, samarium, and gadolinium are available commercially
at a relatively low cost and may be efectively employed.
As noted above, the zeolite material is cation exchanged with a mix-
ture of rare earth, nickel and ammonium compounds according to the instant
invention. Any convenient ammonium compound may be employed although the
chloride is preferred because it is inexpensive and readily available. The
weight ratio of ammonium compound to nickel and rare earth compounds in the
aqueous exchange solution can be selec~ed over a broad range. Generally the
weight ra~io of ammoDlum compound to nickel and rare earth compounds combined
; ~ is wi~hin the range o from about 0~.5:1 to about 20:1, alth wgh the data con-
~ ~ tained herein indicates that a range of from about 0.2:1 to about 5:1 can be
~: :
used with good results. The concentration of rare earth compounds in the
aqueous exchange solution can be varied over a wide range and exchange condi-
tions can be adjusted accordingly such tha~ the rare earth content of the ion
exchanged crystalline zeolite can be selected over a broad range. Generally,
" ~ :
the content of the inal catalyst composite in terms of the rare earth ele-
39 ments is from about 2 to about 25 weight percent. The runs described herein
indicate that the rare earth content of the catalyst can be within the range
:
' ,' "' "
1~73~ -
of from 5 to 20 weight percent. Good results were obtained employing a rare
earth content of about 10 percent by weight. As noted above, the alkali metal
content, for example sodium, of the exchanged catalyst support is partially
removed by the ion exchange step and the alkali metal is generally from about
0.01 to about 2 percent by weight; however, the runs described herein indi-
cate that good results can be obtained employing an alkali metal content rang-
ing from about 0.1 to about 1 percent by weight.
The nickel compounds which will be employed in admixture with the
above-named rare earth metal compounds and ammonium compounds are those where-
in the nickel ion is present in the cationic state. Some suitable compounds
representative of the nickel compounds which can be used in the invention in-
clude the nitrates, bromidesg acetates, chlorides, iodides, sulfates and
mixtures thereof.
The nlckel content in the f-lnal composition can also be selected
over a broad range. Generally the composition will comprise from about 0.01
to about 15 weight percent nickel, although the runs carried out in accordance
with the invention and described herein indicate that good results can be
obtained employing a nickel content ranging from about 1 to about 8 percent
by weight of said composition.
The procedure whereby the Type X and Type Y zeolites are treated
with aqueous solutions of rare earth, nickel and ammonium compounds to replace
a portion of the alkali metal content of the zeolite is a cation exchange pro-
cess ~hich can be carried out in a batch or continuous fashion. Generally the
exchange process i8 carried out on a continuous basis under the following
typical conditions. A fixed bed of the zeolite material is treated with said
. aqueous solution of the rare earth, nickel and ammonium compounds at a temper-
ature of 90 to 110 C. under conditions such that from about 0.1 to about 0.5
of the volume of aqueous salts solution per volume of zeolite is in contact
with said zeolite per hour or~ in other words, an LHSV ranging from about 0.1
to about 0.5 is e~ployed in the e~change process. Under these conditions,
the exchange process can be completed in 48 hours or less to achieve the desired
~73~
level of rare earth, nickel and ammonium ions in the zeolite. The exchanged
zeolite is then washed free of excess lons from the exchange step with water.
The excess wash water is removed by drying the zeolite at a temperature
ranging from about 100 C. to about 3C0 C. just prior to calcination. The
instant catalyst can be calcined before impregnation with the platinim com-
pound to be described below or the impregnation can be carried out prior to
the calcination step. In either case, the calcination is carried out by
slowly heating the zeolite from about 100 to 200 C. to a temperature within
the range of from about 200 to about 550 C. ln order to calcine the zeolite
and convert the ammonium cations to the hydrogen form. Usually, the calcina-
tlon is conducted until a constant weight ls obtained for the zeolitic material,
generally from about 2 to about 10 hours. The calcined zeolite is then cooled
in ambient air, i.e., under conditions of normal humidity.
The above-described support is impregnated with a solution of at
least one platinum compound followed by evaporation of the solvent used in the
impregnation step. Evaporation of the solvent can be conducted under vacuum
if desired. Suitable solven~s include water, alcohols, such as ethanol,
ketones, such as acetone, and the like. Some of the various platinum compounds
that can be employed in the lmpregnation step are as follows: ammonium hexa-
chloroplatinate(IV), ammonium tetrachloroplatinate(II), chloroplatinic acid,diaminoplatinum dlnitri~e, platinic acid, platinum tetrachloride and mixtures
thereof. The impregnation is generally carried out under what may be called
'total impregnationll whereby the entire solids in the solutlons used in the
impregnation are left on the catalyst support and the liquid solvent for said
compounds is simply removed by evaporation.
The platinum content in the final compositlon can be selected over a
broad range. Generally the platinum content ranges from 0.01 to about 1 per-
cent by welght of sald composltion although the runs described hereln indicate
that good results can be obtained employing a platinum content within the
range of from about 0.05 to 0.25 percent by weight of said compositon.
The halogen-containing compounds which can be utilized according to
the instant invention as a source of halide include the elemental halogens
~7~
themselves such as fluorine, bromine, chlorine or lodine and the hydrohalides
of said elements (HF, HBr, HCl and HI). Use of the above compounds generally
requires care~ul control of the addition, and it is preferred to employ organic
compounds which contain halogen in the instant invention. A wide variety
of halogen-containing organic compounds can be employed to provide the
necessary halide for use in the instant invention. These compounds can con-
tain one or more atoms of fluorine, bromine, chlorine or iodine or mixtures
thereof per molecule and the carbon content of such compounds is generally in
the range of from 1 to 4 carbon atoms per molecule. For example, such com-
pounds include alkyl halides, acid halides, or fully halogenated carbon com-
pounds such as carbon tetrachloride or tetrachloroethylene and the like.Examples of other suitable organic compounds which can be employed include
chloroform, bromoform, dichloromethane, dibromomethane, difluoromethane,
chloromethane, bromomethane, 1,4-dichlorobutane, 1,4-dibromobutane, l-chloro-
; butane, l-fluorobutane, l-bromobutane, 1,2-dichloroethane, 1,2-dibromoethane,
2-chloropropane, 2-bromopropane, acetyl chloride, acetyl iodide, acetyl
bromide, bromochloromethane, l-bromo-4-chlorobutane, 1,2-dichloroethylene,
1,2-dibromoethylene and mixtures thereof. From the results of the runs dis-
closed herein, it i6 believed that organic compounds containing chlorine or
bromine will produce the best results and thus such compounds are preferred.
The hydroalkylation catalysts are modified with a halide source com-
pound accordlng to the instant invention by simply adding said halide source
compound to the catalyst prior to or simultaneous with contac~ing the aromatic
hydrocarbon feed in ~he hydroalkylation process. Because such small amounts
of the halide source compound are employed, one method for adding the halide
source compound to the catalyst which has been very satisfactory is to dilute
the halide source compound with the aromatic hydrocarbon feed and thus contact
the catalyst with the feed simultaneously with the halide source compound. It
; is preaently believed that the halogen component of the catalyst whlch has
besn treated with the halide source compound exists ln the halide form and
thus is referred to herein as a halide, but the exact form of the halogen com-
ponent of the catalyst has not been investigated and is not to be a limitation
on the invention.
~973~L~
The amount of the halide added per gram of catalyst utilized i5 an
important aspect of the present invention because too much halide will poison
the catalyst whereas too little halide will not improve the selectivity of the
catalyst to the desired cycloalkyl aromatic hydrocarbon. Thus, the halide con-
tent of the composition is that amount sufficient to improve the selectivity
of the composition to the desired cycloalkyl aromatic hydrocarbon. Generally,
the amount of halide added to the catalyst ranges from about 0.1 to about 100
milligrams of elemental halogen per gram of catalyst; however, based upon the
results of the runs described herein, it is expected that the amount of halide
added to the ca~alyst will more often range from about 0.5 to about ~n milli-
grams of elemPntal halogen per gram of catalyst.
The addition of the halide source compounds to the aromatic hydro-
carbon feed stream can be utili2ed when the catalyst is fresh, i.e., previously
unused, or can also be utilized after one or more regenerations of the above-
mentioned catalyst. As most of the runs described herein indicate, a fresh
catalyst is improved somewhat by regeneration and in many cases it may be de-
sirable to subject a fresh catalyst to the regeneration process prior to using
it. A typical regeneration procedure for the above-described catalyst in-
cludes purgingthe system of hydrogen with an inert gas such as nitrogen, then
allowing air to enter the reaction zone and heatlng ~o a range of 400-500 C. in
the presence of flowing air and malntaining this te~perature in the presence of
flowing air for a total time of about three hours. The catalys is then cooled
in the preaence of flowing air or nitrogen and at a temperature of about 200
;~ C. is reduced with hydrogen for a period of a~out 0.5 to 1 hour. The catalyst
is then cooled to the desired reaction temperature and is then ready for use in
the hydroalkylation reaction. Generally~ it is desirable to retreat the
catalyst with the halogen-containing compound after each regenerattion process
to in~ure that the catalyst will provide the highest selectivity to the desired
cycloalkyl aromatic compound.
Although the compound or compounds which serve as the source of
halide to modify the hydroalkylation catalyst of this invention can be added
.
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to the hydrocarbon feed in one portion, good results were obtained by adaing
the halogen-containing compound to the feed over a period of time, generally
from about 1 to abou~ 3 hours although longer times can and weré employed. It
is believed that a more efficient utilization of the halide source compound i5
achieved by the above-described gradual addition of said compounds to the
catalyst, such as when that halide source compound is added to the hydrocarbon
feed, but in some instances a shorter catalyst modification time may be more
desirable and produce an equal or superior catalyst.
The compositlon described above is employed for the hydroalkylation
of aromatic hydrocarbons to produce cycloalkyl aromatic hydrocarbons. Some of
the feedstocks which are suitable for use in the present invention are aro-
matic compounds, i.e., monocyclic aromatic hydrocarbons and alkyl-substltuted
monocyclic aromatic hydrocarbons. Some specific examples of these are benzene,
toluene, xylenes, and the like, and mixtures thereof. The aromatic hydrocar-
bon feedstocks should be essentially free of sulfur-containing compounds and
other known poisons for hydrogenation catalysts in general. However, it is
believed that a small amount of water, e.g., 5 to 100 ppm, in the feedstock is
beneficial for maintaining catalyst activity over an extended period, e.g.,
several days.
The invention is particularly valuable for the conversion of benzene
to cyclohexylbenzene. Cyclohexylbenzene is known as a valuable solvent and
chemical intermediate. It can be converted in high yield to phenol and cyclo-
hexanone by autooxidatlon with subsequent acid treatment. It is also useful
as an intermediate in the production of cyclohexene which in turn can be uti-
lized for the production of adipic acid and caprolactam.
The aromatic hydrocarbon feedgtock is fed to the catalyst in a re-
action zone operated under a wide range of conditions. The feedstock liquid
hourly space velocity (L~SV), reaction temperature and pressure, and the hy-
drogen feed rate are not parti ularly critical; however, the liquid hourly
space velocity (LHSV) generally ranges from about 1 to about 100, the reaction
pre~8ure generally ranges from about 690 to about 13,800 kPa (about 100 to
~(~9733L~
about 2,000 psig), the hydrogen feed rate generally ranging from about 0.2 to
about 1 mole per mole of aromatic hydrocarbon feedstock per hour, and the re-
action temperature generally ranging from about 100 to about 250 C. ~ased
upon the runs described herein good results can be obtained employing a liquid
hourly space velocity (LHSV) within the range of from about 5 to about 30, a
reaction pressure within the range of from about 1,380 to about 6,900 kPa (a-
bout 200 to about 1,000 psig), the hydrogen feed rate within the range of from
about 0.2 to about l mole per mole of aromatic hydrocarbon feed per hour, and
the reaction temperature within the range of from about 140 to about 200 C.
10The hydroalkylation reaction is conveniently carried out by having
the above-described catalyst in a fixed bed reactor and then contacting said
catalyst with the aromatic hydrocarbon feed and hydrogen in an upflow or down-
flow arrangement. It is also possible to employ a countercurrent flow of hy- --
drogen and the aromatic hydrocarbon feed over the catalyst in the reaction
zone. It is also possible to carry out the hydroalkylation reaction under
batch conditions although a batch process is less preferred because it is nor-
mally more expensive to operate and initial equipment costs are higher based
upon the same size process.
Although a fixed bed reactor is mentioned above, most any type of
raaction zone can be used as the particular type of reaction ~one is not be-
lieved to be a critical parameter of the invention.
The reaction mixture from the reaction zone can usually be convenient-
ly separated into the desired components by simple frac~ional distillation, and
recycle of the unreacted feedstoc~ and unreacted hydrogen can be accomplished
as desired. The hydroalkylation products can be further purified as desired
after separation from unreacted feedstock.
It is generally desirable to pretreat the catalyst with hydrogen
gas prior to contacting the catalyst with the aromatic hydrocarbon in order
to pre-reduce the catalyst. Based upon the runs described hereinafter, the
hydrogen pressure and feed rate for the pretreating step generally is the same
as that to be employed when contacting the aromatic hydrocarbon with the
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catalyst. In the hydroalkylatio~ runs of the examples hereina~ter described,
the catalyst in the reactor was first ~educed at 150 C. for 15 minutes under
3,450 kPa ~500 psig) hydrogen at a hydrogen flow rate of 0,32 liters per minute
before benzene was introduced to the reactor. Hydrogen pressure during the
~ydroalkylation process was maintained at 3,450 kPa (500 psig) and at a flow
rate of about 0.32 liters per minute.
EXAMPLE I
Catalyst Preparation
Tha catalyst utilized in the runs of this Example, designated cat-
10 alyst No. 1, was prepared in the following manner. A glass tube of 45 milli- -
meter diameter, equipped with heating means and means for passing an aqueous
solution of compounds therethrough, was charged with 200 grams of a type X -
crystalline zeolite (Davison 13X mole sieves of 8-12 mesh manufactured by
Davison Chemical Division of W. R. Grace and Co., Baltimore, Maryland). An
aqueous solution of 400 grams of ammonium chloride, 100 grams of rare earth
chlorides, and 200 grams of nickel chloride (NiC12) hexahydrate in 4 liters of
deionized water was prepared. The rare earth chlorides were utllized as a
commercially available mixture of the following co~position: MC13 6H20 where-
in M - lanthanum 23%, cerium 43.5%, praseody~ium 5.4%, neodymium 17.9%, samar-
ium 1.9%9 gadolinium 0.6%, and others 0.2%. The crystalline zeolite material
was firs~ wetted with a portion of the above solution and then charged to ~he
tubular glass reactor described above and the remainder-of the aqueous solu-
tion pumped through the crystalllne zeolite bed, the material was cooled,
filtered, and washed six times with 350 ml portions of water and then allowed
to dry in ambient air. A portion (27`.3 grams) of the cation-e~changed crys-
talline zeolite was then treated with a solution of 0.054 grams of chloro-
platinic acid (H2PtC16) hexahydrate in 25 ml of water under to~al impregnation
condition~. The impregnated crystalline zeolite was dried under vacuum to
glve a weight of 26.2 grams of the zeolite material. This material was then
calcined by heating for about 4 hours in a furnace to about 205 C. (400 F.)
and then the temperature increased slowly up to about 524 C. ~975 F.) over an
13
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eight hour period and then allowed to cool in the air. The catalyst t~us pre-
pared contained 0.1% platinum, 4.68% nickel, 9.5% rare earths, and 0.63% sodium
by weight.
Benzene Hydroalkylation
The catalyst (No. 1) described above was utilized in the hydroalkyla-
tion of benzene in Run No. 1 described below in Table I. In these hydroalkyla-
tion runs, a small tubular reactor equipped for contlnuous reaction operation
was charged with 10 grams tl3 ml) of the catalytic material. The catalys~ was
prereduced at 150 C. under 3450 kPa (500 psig) hydrogen at a flow rate of 0.32
liters per minute of hydrogen for a period of 15 minutes. During each benzene
hydroalkylation run, the hydrogen pressure was maintained at 3450 kPa (500
psig3 and at a flow rate of 0.32 liters per minute of hydrogen. Run ~o. 2 of
Table I was carried out after the catalyst had been regenerated according to
the procedure previously described. Runs 3 and 4 of the table below were runs
of the invention and were carried out after the catalyst had been modified
according to the instant invention by charging 50 parts per million of carbon
tetrachloride in the benzene feed over a period of four hours to provide
0.028 grams of carbon tetrachloride per 10 grams of the catalyst (2.6 milli-
grams [mg] of chlorine [el] per gram of catalyst). Other reaction conditions
and the results obtained in the hydroalkylation runs are shown in Table I.
Tab
Weight
Run Regen- Temp. Benzene Selectivity, Wt. % Ratio
No. CCl eration C. LHSV Conv. % CH(bj CHB(C) CHBtCH
4 - -
1 No No 170 15.6 9.012.2 74.4 6.1
2 No ~es 170 18.0 10.81~.8 69.4 4.7
3 Yes No 175 12.8 12.1 8.3 75.1 9.1
4 Yes No 168 12.8 10.4 9.6 75.0 7.8
(a) Analy~is by gas-llquid phase chromatography (GLC) of reaction zone
effluent.
(b) C~ = Cyclohexane.
tC) CHB = Cyclohexylbenzene.
14
.
~9~3~
A comparison of the results of control Runs 1 and 2 with invention
Runs 3 and 4, particularly noting the ~eight ratio of CHB to CH, clearly demon-
strates the improvement in selectivity to CHB without a reduction in conversion
of benzene but at a lower LHSV when practicing the present invention under the
conditions employed.
EXAMPLE II
The catalyst utilized in the'runs of this Example (cat~lyst No. 2)
was prepared in essentially the same manner utilized for the preparation of
catalyst No. 1 of Example I above.' In this instance, however, the'catalyst
was prepared in a much larger quantity and the'particular catalyst utilized
in Run No. 5 below was a used ca~alyst that had been effectively employed for
a period of time in the hydroalkylation of benzene to cyclohexylbenzene but
which had decreased significantly in activity and selectivity in the hydro-
' alkylation process. In Run No. 6 utilizing this catalyst, the hydroalkylation
procedure was carried out after performing a regeneration process on the cat- -
alyst in the s nner previously described. The results obtained in Run ~o. 6
are also presented in Table II below. Run No. 7 is a run carried out accord-
ing to the instant invention wherein the catalyst used in Run No. 6 was treated
with carbon tetrachloride in the benzene feed over a three-hour period to pro-
vide 0.015 gram of carbon tetrachloride per 12.5 grams of catalyst (1.1 mg Cl
per gram of catalyst).
The runs of Example II described above were carried out utilizing a
reaction system ~or continuous operation as previously described wherein the
reaction zone was charged with 15 ml (12.5 grams) of the catalyst described
earlier. Other conditions utilized in the hydroalkylation runs and ~he results
obtained are shown below in Table IIo
Table II
~ 30 'Run Regen- Temp. Benzene Selectivity, ~t. % ~a~oht
;~; No. ~ eration C. LHSV Conv._% CH CHB CHB/CH
5 No No 190 10.0 1.5 35.8 58.7 1.6
6 No Yes 169 20.0 g.l 9.3 76.4 8.2
7 Yes Yes 167 6.3 11.8 7.5 78.6 10.4
, 15
~73~
A comparison of the results of invention Run 7 with the results of
control Runs 5 and 6 shows an increase in weight ratio of GHB to CH and an in-
crease in selectivity to CHB without a decrease in conversion but at a lower
LHSV under the conditions used when employing a catalyst and the process of
the present invention.
EXAMPLE III
Catalyst No. 3 was prepared in essentially the same manner as cat-
alyst No. 1 of Example I above with the exception that the amount of platinum
compound employed in the impregnation step was sufficient to provide 0.15
weight percent platinum and a small amount of nickel chloride was also added
to the catalyst in the impregnation step such that the final catalyst contained
a total of 4.83 weight percent nickel in addition to 9.5 weight percent rare
earths and 0.63 weight percent sodium. Run No. 8 utilizing the above catalyst
iB a control run wherein the fresh or unused cataly~t was employed. Run ~o. 9
was carried out after the catalyst w~s regenerated in the manner previously
described and Run No. 10 is a run according to the instant invention in which
the regenerated catalyst was modified by the addition of 100 parts per million
of carbon tetrachloride to the benzene feed over a two-hour period to provide
0.030 gram of carbon tetrachloride per 10.8 grams of catalyst (2.6 mg Cl per
8ram of catalyst). The results obtained in these ~hree runs as well as other
reaction conditions utilized are shown below in Table III.
Table III
Weight
Run Regen- T~mp. Benzene Selecti~ity? Wt. % Ratio
No. ~ eration C. LHSV Conv. % ~C~- CHB CHB/CH
a No No 160 17 10.1 15.2 73.2 4.8
9 No Yes 173 20 11.1 15.3 73.0 4.8
-; ~ 10 Yes Yes 172 14 9.8 7.2 80.6 11.1
A comparison of the results of invention Run 10 with control Runs 8
and 9 shows a substan~ial increase in the weight ratio of CHB/CH with only a
5mall decrease in benzene conversion and at a lower LHSV under the conditions
employed.
16
73~
~XAMPLE I~
Catalys~ No. 4 utilized in the :runs of this ~xample was prepared in
essentially the same manner as that described for catalyst ~o. 1 of Example I
above. However, in this instance, the concentration of nickel chloride in the
cation exchange solution was 2.5 weight percent rather than 5 weight percent
as utilized for the preparation of catalyst No. 1. The catalyst (No. 4) thus
prepared contained 0.10 weight percent platinum, 3.18 weight percent nickel
and an estimated 10-11 weight percent rare earths and 0.7 weight pe-fcent
sodium. This catalyst was utilized for the hydroalkylation of benzene under
the conditions of hydrogen pressure and hydrogen flow rate previously described
and the results shown for Run No. 11 were obtained with this catalyst prior to
any regeneration or modification treatment according to the pr2sent invention.
The results with Run No. 12 were obtained with the above catalyst after said
catalyst had been regenerated. Run No. 13 was carried out according to the
instant invention in which the catalyst (after Run No. 12) was treated with
100 parts per million of carbon tetrachloride in the benzene feed over a two-
hour period to provide 0l020gram of carbon tetrachloride per 10.6 grams of
catalyst (1.7 mg Cl per gram of catalyst~. The results obtained in Runs 11,
12, and 13 as well as other conditions employed in the hydroalkylation runs
are presented below in Table IV.
Table IV
_ . _
Weight
Run Regen- Temp. Benzçne Select-lvity9 Wt. % Ratio
No. CCl eration C. LHSV Conv. % CH CHB CHB/CH
--4 _ _
11 No No 170 6.7 7.1 21.1 64.8 3.1
12 No Yes 172 13.3 5.2 23.1 67.3 2.9
13 Yes Yes 170 6.7 5.3 13.6 73.6 5.4
The inven~ion run, Run 13, when compared with the control runs, Runs
11 and 12, aemonstrates that practice of the present invention provides an in-
crease in the weight ratio of CHB to CH and selectivity to CHB with some de-
crease in conversion to benzene and LHSV over Run 12 under the conditions
employed.
~731~L
EXAMPLE V
The catalyst employed in the runs of this ~xa~ple was prepared in
essentially the same procedure as that given for catalyst No. 1 of ~xample I
with the exceptlon tha~ the concentration of nickel chloride in the cation ex-
change solution in this instance (catalyst No. 5) was 10 weight-percent rather
than 5 weight percent as in the case of catalyst No. 1. Catalyst No. 5 also
contained 0.2 weight percent platinum, 6.5 weight percent nickel, 0.72 weight
percent sodium and an estimated 9-10 weight percent rare earths.
Benzene hydroalkylation runs were carried out in the continuous re-
action system previously described with the catalyst described above (No. 5).In Run No. 14, the catalyst was u~ilized prior to any regeneration or modifi-
; cation treatment according to the instant invention. In Run No. 15, the cat-
alyst had been treated with 50 parts per million of carbon tetrachloride in
the benzene feed over a five hour period according to the instant invention to - -
provide 0.033 gram of carbon tetrachloride per 11.5 grams of catalyst (2.6 mg
Cl per gram of catalyst). It should be noted that this treatment was carried
out prior to any regeneration treatment of the catalyst. In ~un No. 16, the
catalyst (after Run No. 15) had been regenerated according to the procedure
previously described and then treated with 50 parts per mlllion of carbon
tetrachloride in the benzene feed for one hour to provide 0.011 gram of carbon
tetrachloride per 11.5 grams of cataly~t (0.9 mg Cl per gram of catalyst).
This run alss is according to the instant invention. Run No. 17 is similar
to Run No. 16 but under different reaction conditions. The runs of this
~xample were carried out using the continuous reaction system previously de-
scribed under the previously described conditions of hydrogen pressure and
hydrogen flow rate. The results of the runs and other reaction conditions
; utili~ed during the runs are presented below in Table V.
Table V
Run Regen- Temp. Benzene Selectivity, W~. % Weight Ratio
~ 30 No. ~ eration C. LHSV Con~. % CH CHB CHB/CH
- 14 No No 164 16 8.7 20.8 60.4 2.9
15 Yes No 170 15 6.6 21.2 62.1 2.9
16 Yes Ye~ 170 15 10.6 9.4 79.2 8.4
17 Yes Yes 165 16 8.3 11.1 78.3 7.0
18
.. . . . ..
' '
~73~
In this series of runs, invention Run 15 gave substantially the same
results as noninvention Run 14. Run 16 shows the improvement in results when
the invention catalyst of Run 15 is regenerated.
EXAMPLE VI
Another series of runs was carried out utilizing another portion of
the same catalyst employed in Example V under somewhat different reaction con-
ditions and a different sequence of treatment steps used to produce the cat-
alyst, catalyst No. 6.
The hydroalkylation runs of this Example were carried out in the
10 continuous reacti.on system previously described and under the condition~ of
hydrogen pressure and hydrogen flow rate also previously described. Run ~o.
18 was made utilizing catalyst No. 6 prior to any regeneration or modification
treatment while Run No. 19 was made after the catalyst had been regenerated
according to the procedure prevlously described. Runs 20 and 21 were made
after the catalyst had been modified according to the instant invention by the
addition of 50 parts per million of carbon tetrachloride in the benzene feed
or a period of 2.5 hours ~o provide 0.022 gram of carbon tetrachloride per
11.5 grams of catalyst (1.8 mg Cl per gram of catalyst). The results obtained
~ in these runs as well as other reaction conditions employed are presen~ed below
;~ 20 in Table VI.
Table VI
~ Ru~ Regen- Temp. Benzene~ Selectivi~y,~Wt. 7~ Weight Ratlo
-~ No. CCl era~ion C. LHSV Conv. % CH CHB CHB/CH
- 4 ~
18 No No 170 17 8.7 43.7 40.2 0~9
19 ~o Yes 190 15 13.4 32.1 64.2 2.0
20 Yes Yes 190 16 8.9 12.4 77.5 6.3
21 Yes Yes 170 13 9.6 14.6 75.0 5.1
Comparing Runs 18 and 19, the improvement resulting from the regenera-
ion of the catalyst is apparent, although some of the improvement may have been
3a due to the higher reaction temperature of Run 19. Comparing Run 19, the regen-
;~ erated cataly~t, with invention ~un 20, the improvement in the weight ratio
of CHB to CH and selectivity to CHB resulting from the practice of the psesent
19
7~1~
invention is seen along with some reduction in conversion of the benzene fe~a
and the LHSV. Invention Run 21 shows a substantial improvement over both
control Runs 18 and 19 even though the reaction tempe~ature is lower than
that used in Run 19; however, the activity of the catalyst of Run 21 is low~r.
EXAMPLE VII
Catalyst No. 7 was prepared in essentially the same manner as that
described for catalyst No. 5 above with the exception that the amount of the
platinum compound utilized in the impregnation step was essentially one-half
of that provided for catalyst No. 5. Thus, catalyst No. 7 contained 0.1 weight
percent platinum, 6.5 weight percent nickel, 0.72 weight percent sodium and an
estimated 9-10 weight percent rare earths.
Catalyst No. 7 was utilized in benzene hydroalkylation runs under the
same conditions of hydrogen pressure and flow rate previously described and
with the same continuous reaction system. Run No. 22 was carried out without
any catalyst treatment such as regeneration or modification with a chlorine-
or bromine-containing compound according to the instant invention. Run No. 23 -
was carried out after the catalyst had received ~he treatment procedure of the
instant invention wherein 50 parts per million of carbon tetrachloride in the
benzene feed was added over a period of 3.5 hours to provida 0.024 gram of
carbon tetrachlorlde per 11.3 grams of catalyst (2.0 mg Cl per gram of catalyst).
Thus, neither catalyst 22 or 23 had been regenerated. The results obtained in
the above runs and o~her reactioll conditions utilized are presented in Table
VII below.
; Table VII
Run Regen- Temp. Benzene S lectivity, Wt. % Weight Ratio
No. CCl eration C. LHSV Co~v. % CH CHB CHB/CH
4 ~ ~
22 No No 160 20 7.8 19.2 69.2 3.6
23 Yes No 160 14.7 10.8 14.8 71.3 4.8
The results of the invention Run 23 when compared with those o~ con-
3~ trol Run 22 demonstrate the improvemen~ resulting from the present invention.
The LHSV o~ benzene in the invention run was lower but the percent conversion
of benzene was higher.
~731~
EXAMPLE VIII
Catalyst No. 8 utilized in the runs of this Example was prepared to
contain nickel, rare earths and platinum on an acidic crystalline zeolite of
type X and also contained a small amount of ruthenium as an added catalyst com-
ponent. This catalyst was prepared by cation exchanging 250 grams of a type X
crystalline zeolite (Davison 13X molecular sieves) with a solution of 400 grams
of ammonium chloride, 100 grams of rare earth chlorides and 400 grams of nickel
chloride hexahydrate in 4 liters of water in a manner essentially the same as
that described above in Example I. The cation-exchanged zeolite was filtered
and washed and allowed to dry in air as described earlier. About one-half of
the cation-exchanged zeolite was calcined under conditions essentially the
same as those described in Example I to provide a support material which con-
tained 6.5% nickel and 0.72% sodium. A portion (41.2 grams) of the uncalcined
cation-exchanged material was impregnated wi~h a solution of 0.0~ gram of
chloroplatinic acid hexahydrate and 0.081 gram of ruthenium trichloride in 50
ml of distilled water. The water was evaporated to dryness on a rotary evap-
orator. The impregnated support was then calcined by heating to about 204 C.
(400 F.) overnight and then lncreasing the temperature to about 518 C. (965
F.) over an eight-hour period. The calcined ca~alyst was allowed to cool in
ambient air and was then ready for utilization in benzene hydroalkylation runs.
The final catalyst thus contained 0.1% pla~inum~ 0.1% rutheniu~, 6.5% nickel,
0.72% æodium and an estimated 9-10% rare earths by weight.
Run No. 24 utilizing the above-described catalyst was carried out
without any modlfication of the catalyst such as by regeneration or addition
of a halide-containing compound according to the instan~ invention. Run No.
25 was carried out after the catalyst had been treated wi~h 50 parts per million
of carbon tetrachloride in the benzene feed for a period of 2.5 hours to pro-
vide about 0.025 grams of carbon tetrachloride per 11.2 grams of catalyst (2.0
mg Cl per gram of catalyst~. Run No. 26 was carried out after the catalyst
utilized in Run No. 25 had been regenerated under typical conditions described
earlier and then again treated with 50 parts per million of carbon tetrachlor-
ide in the benaene feed for 1.5 hours to provide about 0.015 gram of carbon
~7~
tetrachloride per 11.2 grams of catalyst (1.2 mg Cl per gram o~ catalyst~, Ihe
hydroalkylation runs were carried out under the previously descrioed conditions
of hydrogen pressure and flow rate. The results are described in Table VIII.
Table VIII
Run Regen- Temp. Benzene Selectivity, Wt. % Weight ~atio
No. CC14 eration C. LHSV Conv. % CH CHB CB /CH
24 No No 175 18 6.6 53.0 43.9 0.8
25 Yes No 175 18 8.2 42.7 53.6 1.3
26 Yes Yes 175 6.7 8.6 15.1 72.1 4.7
A comparison of control Run 24 wlth invention Run 25 shows an im-
provemen~ ln the results due to treatment of the catalyst of Run 25 in accord-
ance with the invention~ but since neither catalyst was regenerated the weight
ratio of CHB to CH and se~ectivity to CHB was rather low. A comparison of in-
vention Run 25 with invention Run 26 employing the regenerated cayalyst of Run
25 but at approximately 1/3 the LHSV of Run 25 shows the substantial improve-
ment brought about by regeneration of the catalyst under the conditions em-
ployed. The addition of ruthenium to the catalysts of Runs 24, 25 and 26 does
not appear to promote the desired reaction under the conditions employed.
EXAMPLE IX
Catalyst No. 9 was prepared in a manner similar to that utilized for
the preparation of catalys~ ~o. 1 of Example I with the exception that in the
cation exchange s~ep the mix~ure of rare earth compounds was replaced by a
single rare earth compound. In this instance, cero~s chloride (CeC13) was
utiliæed in the cation exchange step. In the preparation of this catalyst,
;~ 200 grams of a type X crystalline zeoli~e (Davison 13~ mole sieves) was wetted
with a portion of a solution o 400 grams of ammonium chloride, 200 grams of
nickel chloride hexahydrate and 100 8rams of cerous chloride in 4 liters of de-
ionized water. The crystalline zeolite material was then charged to the cation
exchange reactor previously employed and the remainder of the above-described
solution pumped over the zeolite bed at a temperature of about 100 C. and at
about 0.25 LHSV. The material was coolad, filtered and washed six times with
22
~97~
350 ml portions of water and then permitted to dry in ambient air A portion
(60 grams) of the cation-exchanged crystalline zeolite was impregnated with a
solution of 0.0966 grams of chloroplatinic acid hexahydrate in abou~ 50 ml of
absolute ethanol. The ethanol was removed under redueed pressure and addi-
tional ethanol added and then removed as before. The catalyst was calcined
under conditions simllar to those previously employed, that is, heating up to
about 205 C. (401 F.) and holding at this temperature overnight followed by
heating over an eight-hour period up to about 524 C. (975 F). This catalyst
(No. 9) contained 0.091 weight percent platinim and an estimated 4-5 weight
percent nickel, 9-10 weight percent cerium and 0.6 weight percent sodium.
Run No. 27 was a benzene hydroalkylation run using the above-
described catalyst prior to any treatment such as regeneration or modification
by addition of a halide-containing compound according to the instant invention.
Run Mo. 28 was carried out by treating the catalyst according to the instant
invention with 50 parts per million o~ carbon tetrachloride in the benzene
~ feed for a period of 3 hours to provide 0.020 g carbon tetrachloride per
- 11.3 grams of catalyst (1.6 mg Cl per gram of catalyst). Run No. 29 was car-
ried out following regeneration of the catalyst used in Run No. 28 under con-
dition~ previously described but without retreating the catalys~ with CC14
subsequent to regeneration. Run No. 30 was carried out by treating the regen-
erated catalyst according to the instant invention with 100 parts per million
of carbon tetrachloride in the benzene feed for a period of 2.5 hours to pro-
vide 0.041 gram of carbon tetrachloride per 11.3 grams of catalyst (3.3 mg Cl
per gram of catalyst). These benzene hydroalkylation runs were carried out
under the conditions of hydrogen pressure and flow rate previously de~cribed.
The results obtalned in Runs 27-30 and other conditions employed in the hydro-
alkylation runs are presented in Table IX below.
Table IX
Run Regen- Temp. Benzene Selectivity, Wt. % Weight Ratio
~o CCl eratlon C LHS~Conv. % CH CHB CHB/CH
27 No No 203 2012.2 51.6 45.9 0.9
28 Yes No 158 6.713.8 29.7 67.6 2.3
2g No(a) Y2s 184 1412.1 31.6 65.7 2.1
30 Yes Ye3 173 148.8 14.5 76.6 5.3
(a) The catalyst was not retreated with CC14 after regeneration.
23
:1~97~
The results shown in Table IX show the improvement in the result~
when employing the present invention whether a mixture of rare earths is used
as in the previous runs or a single rare earth, cerium, is used as in invention
Runs 28-30.
EXAMPLE 2
Catalyst No. 10 utilized in the runs of this Example was prepared in
essentially the same manner as that described for catalyst No. 9 above with the
exception that the cerous chloride was replaced by lanthanum chloride (LaC12)
hexahydrate in the cation exchange step. A portion (50 grams) of the cation-
exchanged crystalline zeolite was impregnated with a solu~ion of 0.095 gram of
chloropla~inic acid hexahydrate in about 50 ml of absolute ethanol. The etha-
nol was removed under reduced pressure, more ethanol added and then removed as
before. The recovered material was heated under calcination conditions similar
to those previously employed in the preparation of catalyst No. 9~ The cata-
lys~ contained 0.1~ platlnum and an estimated 4-5% nickel, 9-10% lanthanum
and 0.6% sodium by weight.
Catalyst No. 10 was employed in Run No. 31 for hydroalkylation of
benzene prior to any treatment of the catalyst by regeneration or modification
by addition o~ halide-containing compounds according to the instant invention.
Run No. 32 waa carried out after the catalyst (No. 103 had been regenerated
under conditions previously described. Run No. 33, a run according to the
instant invention, was carried ou~ after the regenerated catalyst had been
modified by treatment with 100 parts per million of carbon tetrachloride in
the benzene feed added over a 4.0 hour period to provide 0.055 gram of carbon
tetrachloride per 11.1 grams of catalyst (4.5 mg Cl per gram of catalyst).
The~e hydroalkylation runs were carried out under the previously employed con-
ditions o~ hydrogen pressure and hydrogen flow rate. Results obtained in
; Run~ 31-33 are shown below in Table X along with other reac~ion conditions
employed in said runs.
24
'~,
. '' . ' ' , ' ' '
7~
Tabl2 X
Run Regen- Temp. Benzene Selectivity, ~t. % Weight ~atio
No CCl eration C. LHSVConv. % CH CHB CHB/C~
31 No No 159 20 7.5 31.7 67.6 2.1
32 No Yes 185 23 13.6 21.1 68.2 3.2
33 Yes Yes 179 16 6.9 14.2 76.1 5.3
Invention Run 33 as compared to control Runs 31 and 32 illustrates
that practice of the present invention produces an improvement in weight ratio
of Cl~ to CH and in selectivity to CHB at a somewhat lower LHSV and conversion
of benzene. Run 33 also demonstrates that the rare earth lanthanum can be
employed in carrying out ~he pre~ent invention.
EXAMPLE XI
Catalyst No. 11 utilized in the runs of this Example was prepared in
essentially the same manner as that described for catalyst ~os. 1 and 2 of
Examples I and II, respectively, with the exception that the chloroplatinic
acid was impregnated after the calcination step. Thus, the amount of platinum,
nickel, and rare earths on the final hydroalkylation catalyst was essentially
the same a~ those shown for the above-mentioned catalyst Nos. 1 and 2.
In Run No. 34 u~ilizing catalys~ No. 11, the hydroalkylation run was
carried out with the catalyst prior to any regeneration or modific~tion treat-
ment according to the instant inven~ion. Run No. 35 was carried out af~er the
catalyst had been modified by the addition of 50 parts per million o carbon
tetrachloride in the benzene feed for a three-hour period to pro~ide 0.026
gra~ of carbon tetrachloride per 11.0 grams of catalyst (2.2 mg Cl per gram of
catalyst). Run No. 36 was also carrled ou~ after the above modification de-
sc~ibed for the catalyst employed in Run No. 35 but under slightly different
reac~ion conditions. These hydroalkylation runs were carried out under the
:
same hydrogen pressure and flow rate and in the same continuous reaction
system as that previou~ly utilized in the Examples above. The results obtained
in these hydroalkylation run~ as well as the other reaction conditions utili~ed
are presented belc~ in Table XI.
~7~
Table XI
Run Regen- Temp. Benzene Selectivlty, Wt. % Weight Ratio
No. ~ eration C. LHSV Conv. % CH CHB CHB/CH
34 No No 185 21.5 12.8 21.6 67.3 3.1
Yes No 185 19.0 10.5 11.4 73.3 6.4
36 Yes No 175 18.8 8.6 12.1 73.2 6.1
Comparison of control Run 34 with invention Run 35 demonstrates an
improved result in the weight ratio of CHB to CH and in selectivity to CHB,
although the invention catalyst was somewhat less active. The different reac-
tion conditions of Run 36 appeared to reduce the catalyst's activity a littleas compared to Run 35.
EXAMPLE_XII
The catalyst employed in the hydroalkylation runs of this Example
was a portion of the same catalyst utilized for the runs of Example XI abo~e. -
~ The hydroalkylation runs were carried out under the same conditions of hydro-
;~ gen pressure and flow rate and in the same type of continuous reaction system
previol-sly employet. Run No. 37 was carried out prior to the treatment of the
catalyst in a regeneration procedure or by addition of a halogen-containing
compound to modify the catalyst accordlng to the instant invention. Thus, Run
No. 37 is similar to Run No. 34 of Example XI except that the reaction condi-
tions were different. Run No. 38 was carried out after the catalyst utilized
in Run No. 37 was regenerated according to the typical procedure previously
~::
descri~ed. Run ~o. 39 was carrled out after the regenerated catalyst had been
modifled by the addition of 50 p rt~ per million of carbon tetrachloride in
the benzene feed over a period of 5.5 hours whlch provided 0.0325 gram of car-
bon tetrachloride per 12.5 gram~ of catalyst (2.3 mg Cl per gram of catalyst).
The results o these hydroalkylation runs as weIl as other reaction conditions
employed are presented in Table XII.
Table XII
Run Regen- Temp. Ben~ene Selectivity, Wt. ~ Weight Ratio
No. ~ eration C. LHSV Conv. % CH CHB CHB/CH
37 No No 170 13.3 10.844.4 52.3 1.2
38 No Yes 170 18.0 15.626.7 64.7 2.4
39 Yes Yes 175 12.0 10.2 7.0 81.4 11.7
::
26
.:;',,', ........ ,i "" ,, ~"" . ~, ,
.
. . ... . . .
3~ 3~
A comparison of cGntrol P~un 38 with 37 shows that regeneration im-
proves the catalyst; however, comparing these runs with invention Run 39 shows
that the invention catalyst provided a substantial improvement in weight ratio
of CHB to CH and selectivity to CHB but with a reduction in activity.
In summary, the results shown in Tables I-XII above demonstrate that
a hydroalkylation catalyst comprising platinum, nickel, rare earths on acidic
mole sieves modified by the addition of a halogen-containing compound provides
an improvement in selectivity of the benzene hydroalkylation process for cyclo-
hexylbenzene. This improvement in selectivity is seen to be achieved before
or after the hydroalkylation catalyst has undergone a regeneration process in-
volving a burn-off of coke or other carbonaceous deposits from the catalysts.
Generally speaking, the improvement in selectivity for cyclohexylbenzene is
accompanied by a decrease in catalyst activity as seen by reduced benzene con-
versions or reduced flow rate of benzene feed through the reaction zone (LHSV).
.
