CA1114403A - Process for producing unsaturated hydrocarbons - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A process for producing unsaturated hydrocarbons which comprises contacting of paraffin, monoolefine and/or alkylaromatic compounds with a catalyst at a temperature within the range of from 400 to 700°C in the presence of an inert gas and/or steam. The catalyst comprises a carrier with deposited thereonto an oxide compound of molybdenum in an amount of from 5 to 35% by weight of the catalyst. As the carrier use is made of a granulated porous crystalline silica modified with magnesia in an amount of from 1 to 20%
by weight of TiO2, or a granulated magnesium-aluminium carrier consisting of 70 to 95% by weight of MgO and 5 to 30% by of from 400 to 700°C till restoratio of catalytic activity of the catalyst. The process according to the present invent-ion ensures a high selectivity; substantially simplifies temperature control in the reaction zone; avoids the pos-sibility of formation of a hazardous mixture of hydrocarbons with oxygen; simplifies purification of waste waters.

Description

PROCESS FOR PRODUCING UNSA~URA'~ED
HYDROC~RBONS
'~he present i~vention relates to the production o~ un-satura~ed hydrocarbons.
Said unsaturated hydroc~rb~s such as butylenes, iso-amylenes, divinyl, isoprene, styr~ne, vinyltoluene are va-luable mo~omers ~or tha ma~u~acture of various typ~s o~ sy~
thetic rubber, plastics, elastomers as w~ll as the starting products ~or the industry o~ basic orga~ic synthesis.
Know~ in the art are various processes ~or tha produc-tion o~ unsaturated hydrocarbons.
~ hus, known i.9 a process ~or the production of unsatu-ratad hydrocarbons ~rom saturated ones at a ternperature within the ranga o~ ~rom 400 to 800C in the presence of a ga~eous oxyg0~ and a catalys-t containin~ molybdenum as well as nickel or cobalt~ ~he yield of butadiene produced by this process aoes ~at exc~ed 10.1% wit~ the selectivity relative thereto of 31.0% and xelative to the total butylenes-buta-diene of 46.~%.
~ l~o known i~ the art is a proce~s ~Dr produci~g mono-a~d di~olef ines by way o~ a~ oxidizing dehydrogenation o~
paraI^~i~s at a temperature within the range o~ from 400 to 700C in the presence of gaseous ox~gen and a ¢atalyst csn- -sisting o~ oxides 4~ molybd~um and/or tungste~ a~d at Least one o~ the ~ollowin~ metals: chromium, man~anese, iron, ~ick-el and ~admium. In accordance with thiQ process9 the yield of ., ~ ' .

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butadiene from n-butane does not exceed 21.6% wi~h sel~cti-vity relative ther~to o~ 53.6% and r~lative to the total of bu~ylenes-butadienq o:E 64-.8%.
A principal disadvantage of -the above-discussed prior art processes resides in a low con~ersion o~ dehydrogenated hydrocarbons and i~su~fici~nt selecti~ity relative to the desired products.
~ he closest analogu~ o~ the process according -to the present invention is a process ~or produc.i~g mo~o-- a~ di-olefines by a~ oxidizing de~gdrogenation of, e.~. para~in hydrocarbo~s, at a temperature within ~he ran~e of from ~00 to 700C and the molar ratio o~ oxygen to the paraffin h~d-rocarbon of ~rom 0~1 to 3~0:1 i~ the presence o~ a~ inert vehicle such as argo~, ~itrogen~ helium, steam or mixtures thereof D
~ he process is conducted o~ a ca~alyst comprising o~ide compou~ds of~ e.g., molybde~um and magnesium, with additives o~ cobalt, iron, chromium~ vanadium~ nickel~ silicon3 ~i~7 boron, bismuth9 tita~ium, niobium~ gadoli~ium9 dysprosium9 gallium and zirconium. ~he yield o~ b~tadiene ~rom ~-bu~a~a by this process is 36.6% with selectivit~ relative thereto o~
54.7~0 and relative to the total o~ but~le~es butadie~e of 64.3%~
For increasing the mechanical strength o~ the catalyst;
the active component is applied onto a carrier, such as alu-mosilicate, aluminium oxide, silica gel. However, the use of such catal~sts, e.g. with the applicatio~ o~ alumosilicate, , ~
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' " " ' ' " ' ' ` ' . " ' " ' . ' ' ' ': ' ' ', ', ' ' . ~ ' ' '" ' , ' ' ' . ' ' ~ ~ ' . ~. .. ' ,' ~ ' ' ,' . . ",' '' ' ' ', ~ '' ' ~ 3 --in accorda~ce wi~h -the above cited meth.od9 leads to low~rin~
of th~ butadiene yield from n-butane dow~ ~o 4.7% with the selectivity thereto o~ 140 3%~ '~hus, the method is characte-rized by a low selectivity also, and~ in ~he case of usi~
a catalyst wi-th a carrier, by a low yield of` the desired dehydro~enation products.
It is an object of the present invention to provide such a process ~or pxoducing unsa-turated hydrocarbons which would make it possible to increase -the yield o~ -th~ desir~d products and increass selectivity o~ the proc~ss.
~ 'his and other objects o~ the prese~t i~vention are accomplished by that in a process ~or produc~ng unsaturated hydrocarbons by contac-ting para~i~, mono-ole~i~e a~d/or aromatic compounds with a ca-talyst comprising a carxier with a deposited thereo~to an oxids compound Q~ molybdenum i~ an amount o~ ~rom 5 to 35% by weight o~ the catalyst in the pr0sence o~ an inert gas a~d/or steam at a temperature with-in the range o~ from 400 to 700C, i~ accordance with t~e present i~ve~tio~, in ths catal~st as the carrier use is made o~ a gra~ulated porous cr~stalli~e silica modi~ied by mag~esia i~ an amount o~ ~rom 1 ~o 20% by weight of the cax-rier, a gra~ulated magnesium-titanium carriar consisting o~
50 to 95% by weight 0~ ~gOs and 50 to 5~0 by weight o~ TiO29 or a granulated mag~2sium-alumi~ium carrier consisting o~
70 to 95% b~ weight o~ MgO and 5 to 30% by weight o~ A1203, a~d at a temperatuxa wi~hin tho ran~e o~ ~rom 400 -to 700C

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~ 3 an oxyOcn-containing gas is passed through ~he spent cata-lyst till regeneration o~ the ca-~alytic ac-tivity of the catal~st.
As the starting material use may be made o~ various organic compounds, namely ole~in~, paraf~in and alkylaroma-tic hydrocarbons. In the oase o~ using paraf~i~s along wi~h dienes there is ~ormed a certain amount o~ monoole~i~es which togather with -the ~nreac-ting starting ma-terial are recycled back into the xeaction æo~e to increase the yi~ld of diene hydrocarbons.
Selectivity of the process is increased upon dilution of the startin~ hydrocaxbons with inert dilue~ts; ~amely nitrogen, argon, st~am and the li~e. Molar ratio between the hydrocarbon a~d the diluent is varied within a Y~ide ra~-g9 0~ from 1:3 to 1:30.
Vapours o~ the starting ~eed (butane 9 butyle~es, iso-pentane, isoamylenes, othylbanzene, e~hyltoluene and the like) in a mixture with a diluant are contacted with the catalyst at a temperature within the range o~ ~rom 400 to 700C (preferably from 450 to 650C). ~s a result, a process of dehydrogenatio~ o~ the starti~g orga~ic compounds occurs~
wherai~ hydxogen o~ said compounds is combi~ed with oxygen of the catalyst with the :Eormation of the reaction wa-ter.
~ he content o~ oxy~sen i~ the catalyst is lowered., ~his re-sul~s in decrease of val~llc~r o~ molybdez~um. Reduction of the catal;srst is accompa~ied by a decr0ase o~ its activit~ and ' ~

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~ 3 substantial loss of activi-ty o~ the feecl conversionO ~'hera-with, selectivity o~ the catalyst action is retained at the i~itial level or even increased.
~ o maintain a hi~h activity o~ the catalyst 9 periodic oxidizing regeneratio~ o~ the cata~yst is per~rmed by means o~ a~ oxygen-containing gas such as air at a tempera-ture within the range o~ ~rom 403 -to 700C~ ~pon the o~id-izing rageneration there occurs elimination of carbonaceous deposits ~rom the ca~aly~t sur~ace and oxidation of the ca-talyst to its original s-tateO ~fter discontinuation o~ each stage of the dehydro~enation a~d regeneration process9 the catalyst is purged with a stream of an inert gas. 'l'here~ore, in accordance with the present inve~-tion, there is no contact o~ the hydrocarbon with oxyge~ in the gas phase which increa-ses selecti~ity o~ the process and elevates ths yield o~ the desired products du~ to the diminished role of the rsactio~s of deep and partial oxidation and o~idizing crac~ing of ~yd-rocarbons~
~ he cata}yst according to the pxese~t i~entio~, as it has bee~ already me~tioned herei~before~ comprises a carrier with deposited thereonto a~ oxide compound o~ mol~denum.
In the catalyst containing, as the carrier~ a granulated crystalline silica modi~isd with mag~esia7 a high mecha~ical strength o~ the ca~alyst is ensured at the acGou~t o~ a rigid crystal lattice o~ silica~ whila the presence o~ magn~sia at .

~ 3 its surfaca results in ths formatiorl of an active ma~sesium molybdate and a subst~ntial (by 10 to 40 tirsles) increas~ o~
a speci~ic sur~ace area of t-he catalyst~
The granulated small-size carrier used i~ tha process according to tha presant inv3ntion co,~prises a mixture of ma~nesia with titanium diDXide or alumina Increased content of magnasia in the carriex cDmposition up to 50 to 95% by weig~t cDntributes to an increased yield o~ the dasired products and higher selectivity of tho dehydrogenation 2rocess~
The presence of titanium dioxide or alumina incrca~s r~c~-nical stre~gth of the carrier and makes possible to lower calcination temperature during its preparation.
The process of dehydrogenation o~ hydrDcarbons may be also conducted on catalysts the active phase o~ which conta-ins~ in addition to oxide compounds o~ molybdanum, oxide com-pounds o~ cobalt, nickel, irDn or manganase in an amou~t o~ from 3.7 to 15% by weight o~ the catalyst. ~uch catalysts have di~ferent structural modi~icatio~s~ The catalyst type a~fects selectivi~y o~ the process of dehydrogenation o~ par-ticulax hydrocarbons~
~ he catal~st i9 employed in the shape o~ tables9 noodles, rings a~d granul~s of various dimensions9 pre~arably of ~rom 0001 to 15.00 mmO
I~ order to prolo~g the sa~vica li~ of the catalyst which is essential ~Dr dehydrogenation process performsd i~
~ ~ a statio~ary a~d liqui~iad bed of the catalystt into tha ,~ , .

- ~ . :~ ~ , : , dehydxogenation zone there is added a small arQoun-t of ox~gen (up to 0~1 mole per mole o~ the starting hydrocarbon feed)~
This is o~ a grea-t importanceg since the opera-tion ti~e of the catalyst (duration o~ dehy~o~enation) in apparatus wi-th a stationar~ bed or in reactors with a fluidized bed usually exceeds 3 to 5 minutes. '~he use o~ small amounts o~ oxygen in the dehydr~genation zone doec; not substantiall~ a~ect the ~ield o~ the desired product;s and selectivit~ o~ dehydro genation.
In accorda~ce with the present i~entlon, the catalyst employed in the pxocess ~or producing unsaturated hydrocar bons is prepared by impregnation oX the a'oove-mentioned car-riers with a~ a~ueous solution o~ ammoni~a molybdate to yield a suspension. From the resultlng suspension water is removed by evaporation, A~ter evaporation t~e thus-obtained mass is subjected to calcination at a tempera-ture within the ran~e of ~om 350 to 700C. ~he calcinatio~ is e~feGted in an inert or oxidi~i~g medium.
During the impregnation of the carrier with an aqueous solution o~ ammonium mslybdate there occurs ~illing o~ the carrier pores with -this solution. I~ the subseque~ treat~ent operations (evaporation, calcination) there occurs ~orming of a catal~st as a result o~ the removal o~ water and decomposi-tion of ammoni~ molybdate~
To intansi~y -the process o~ deh~dration o~ the suspen-sion, it is advisable to carry out the evaporation under ; vacuum.

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13L~lL9L9Lr~3 In some cases in the calcination proces~ sintering OL
particles is possible at a rapid growth of t~mperature Y~hich results i~ varioations o~ the ~raction composition o~ the catalyst and this, in -turn, necessitates inclusio~ of addi-tional staOes such as crushing, separation. To avoid this, calcination o~ the resulting mass should be pre~erably caxri~
ed out in a suspended bed.
In oxder to increase activity and selectivity of the catalyst, it is advisable to include into its composition oxide compounds o~ cobal-t, iron, ~ickel or manga~ese in an amount o~ ~rom 3.7 to 15% by wei6rht o~ th~ catalyst. ~o this end, p~ior to calcination the carrier is also impregnated with an aqueous solution o~ cobalt ~itrate, or nitrate o~
nickel, iron or man~anese; -this impregnatio~ and said impreg nation with an aqueous solution of ammo~ium molybdate i~ any succession~ in doing so, inbe-tween two said impre~natio~s wa-ter is removed from the resultin~ suspension by evaporatio~.
~In order to ~urther incr~ase activity and selectivity o~
;the catalyst, it is advisable to repeatedly a~d alternatively (up to 3 -12 tLmes) per~orm impreg~ation o~ t~e carrier with sol~tion o~ said salts including ammonium molybdate, ~ollowed by evaporatio~ o~ water ~rom the suspension. Thereafter cal-cinatio~ of the resulting mass is c ~ ried ~ut at a temperatu-re of from 350 to 700C. ~his ensures a more un~or~ distribu-tio~ of the active phase wi-thin the volume of the catalyst granules and increase of ~i~e~ess of the active compone~t at the sur~ace of t;he porous carrier.

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:-. ' . . - -., : . : :,',.. . ' , , ' _ 9 ~ 44~3 Increased fineness o~ the active component is associa-ted with the growth of its sur~ace area accessible ~or the reagents which~ in turn~ make3 i.-t possible to per~orm the dehydrogenation process at a higher rate at the sa~e char~e of the catalyst. Unif ormity of distrib~tion o~ the ac-tive component wi-thin the volume o~ the ca-lalys-t granules prev-e~ts from a rapid loss o~ -the cat~lyst activity upon wear thereo~ duri~g the opera-tion~
Further i~crease o~ the catalyst activit~ and simplifi-cation o~ the technology o~ its preparation is ensured b~
that -the resulting maæs~ i.e~ carrier, impregnated with aqueous solutions o~ ammonium molybda-te and a nitric acid salt and dried, prior to the calci~ation is treated with an aqueous solution o~ ammonia, amines or amin~alcohols ~ollow-ed by the removal of wa~er by evaporation.
'rO this end, use may be made o~ methyl and triethyl-amines, mono-, di- and triethanolamines and ~he like. '~he -treatment therewith makes it possible to achi~ve a u~i~orm distribution o~ acti~ components within the volume o~ the catalyst granules and exclude repeated operations in the preparation o~ a polycomponent catalyst.
'l'he use in -the process according -to -the present i~e~-tion o~ the principle o~ alternative con~tacting o~ the hydro-carbons ~ed -to .hydrogenation and oxygen supplied to regenera-tion o~ the spent catalyst makes i-t po~sible to increase the process svlectivLty as oompared to the prior art processss ,. ~ .
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(c~. US ~abent NoO 39~629256)~ ~hus7 uporL deh~droge~ation o~ n-butane accordi~g -to the p~ocess o~ the ~rasent i~ven--tion~ salec-tivity relative to butadiene ls 75.1% as compared to 5'~% in the prior art process7 while select:ivity relative to the total o~ butylenes butadiene constitutes 85.4% as compared with 64.3% in -the prior ar-t process9 ~ his relatively low selec~tivi-ty in the production o~
unsatuxated hydrocarbons by the known method is appare~
due to in-tensive side reactions o~ a deep and partial o~ida-tion o~' hydrocarbons in ~the prese~ce o~' gaseous oxygen supp-lied i~to the dehydro~enation zone along with ~the starting feed. A similar decrease in selectlvity relati~e to dehydlo-genation products ~der the conditio~s o~ simultaneous supply of hydrocarbo~s and air oxyge~ onto the catalyst has baen ob served in our case too. ~hus9 when the process is carriad out in the absence o~ gaseous oxygen in the reac-tion zone, the yield o~ butadiene ~rom n-butane is 27%9 ths yield o~
combustio~ products (CO and C02) is 8~6%. Upon addition o~
oxygen into the starki~g ~eed composition at the stage o~
dehydrogenation only in~the amou~t o~ 0~5 mole per mole o~ ~
n-buta~e, the yield o~ butadie~e is reduced -to 22~2~o~ whila the yield o~ combustio~ products is i~creased to 20~2~o~ whe-reas total selecti~ity r~lative to the whole of the deh~dro-genation products (C4H8 - C~,H6) is reduced ~rom 7500 -to 5401%. ~he yield o~ the products o~ partial oxydatio~ o~ hyd-. . .. . . . . .
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44~33 rocarbons, i.e. :~uran and o-the~ oxygen-co~-tainin~r compounds7 i~ this case is i~creased by a~out 5 times.
.~urthermore, carryln~ out the process in the absence o~
oxygen ~acili-tates the temperature control ln the reactio~
zo~e (owi~g bo lowered intellsity o~ highly exothermal combus-tion reactio~s); there is totally avoided the possioility of the ~ormation of a hazardous mixt;ure oP hydrocarbons with oxygen; also substantially simpli.~ied is the problem o~ puri-~icatio.~ o~ waste wa-terq due to a lowered yield o~ oxygen -containing products o~ a partial oxidation o~ hydrocarbons, Due to the ~act that the stock of` oxygen in the catalyst is limited, -the period of` its eff`ective operatio~ under the conditions of dehydrogena-tion is not long7 which is a subs-t-antial obstacl6 to practical implementation o~ the process, . . ~o avoid this, it is advisable to conduc-t deh~dro~enation ; ~ollowing the process according to the present inve~tio~
i.e. with continuous displacement o~ the spent ca-talyst from the dehydroge~ation zone to the rege~eratio~ zone, with sub-sequent recycle o~ tha catalyst bac~ to the dehydrogenation zone after restoration o~. its activity. ~his displaceme~t o~
the catal~st and its operation in a suspe~ded bed imposes i~-creased requirements o~ the mecha~ical strength a~d wear-resi-sta~ce of the catalyst and makes practicall~ impossible the use o~ catal~sts prepared b~ the p~ior art methods without a carrier.

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~3 At the same time, the use o~ catalys-ts prepared by the prior art method with a carrier leads to a sharp reduction of the yield of the desired products o~ dehydrogenatio~ of hydrocarbons.
~ he catalyst as employed i.~ the proc~ss accordin~r to the present iLven-tion, allows the desired produ~ to be obtained in a high yield. Moreover~ -this catalyst, owing to a mecha~ically durable porous carrier fea~ures a hi~h wear-resistance a~d abili-ty o~ retai~i~g i~s ~ractional composi-tion whic}l enables i-ts use in appaxatus with both s-ta-tionary and mobile or li~ui~ied bed o~ the catalyst~
~ he porous crystalline silica as used as a carrier ~or the catalyst in the process accoxding to -the present in~en-~io~ nas a small sp~uifi~ sur~ace area (within th~ rangQ o~
~rom 0.15 to 2 m2/g) and a low absorptio~ power relative to the active components of the catalyst~ ~odi~ication thereof with magnesia ma~es it possiblQ to i~crease the speci~ic sur Yace area o~ ~he carrier up to 10 - 12 m2/g. Magnesia, while reactinæ during its application with the solutio~ o~ a~monium molybdate, Iorms a magrnesium moly~aate which is c~talytically active Ln the dehydrogenation reaction, a~d in the prepara-tion o~, ~or.example, a cobalt-moly~denum catalyst, it stabi-lizes the active a-pnase o~ cobal~ molyodate.
In the process according to the present inventio~ use may be also ma~e o~ a catal~st having, as its carrie~, a moulded ~nd calcined mi~ture o~ ~insly divi~ed ma~nesia a~d .... :' ' .

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~ 3 titania or alumina. In this case magnesia Lorr~s a ma-trIx o~
the carrier granule, while the incorporatad therein titania or alumina substantially lowers the calcinatio~ temperature o~ granules and makes it possible to obtain t~e carrier wi~h a su~icientl~ developed specific sur~ace area~ since speci-~`ic area o~ magnesia is conside:rably reduced with the gro~Jth of calcination tempera~ture.
l'he catalysts used in the process according to the pre-sent i~vention possess a high catalytic activity and sele-ctivity, thermal stabili~y, impact resistance and ability to withstand considerable te~nperature gradients~ ~hus; wear o~
a small-size cobalt molybdenum catalyst based o~ magnesiu~--titanium carrier constitutes 3- 4%~ while the sta~dard cru-shed glass-like alumosilicate under the same co~ditions haS
a wear o~ l8- 20% b~ weight. ~till higher wear~resista~ce is characteristic o~ catalysts based on a porous cr~stalline silica (quartz). ~here~ore, the catalysts according to the present inventio~ are highly e~fective in de~ydrogenation process in reactors o~ all the above-me~tioned types~
~ he procass according to the E~esent i~vention is tech-nologically simple and may be per~ormed in the ~ollowing manner.
: According to the p~esent i~ention~ production o~ u~sa-turated h~drocarbons by wa~ o~ dehydrogenation of para~in, monoole~ine and/or alkylaromatic compounds is ef~ected by con~acting the~ vapours ~ith the above-described catalyst ' .. , ' ~,. ' .
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_ lL~ _ a-t a temperature ~ithin the ran~e o~ ~rom 400 to 700C in apparatus o~ di~erent design4 In order to increase selecti-~ity of dehydrogenation~ the ~eed vapours are diluted wi-th steam and/or an inert gas such as nitrogen3 argon, heliu~
In the periodic scheme o~ operation, into an app~ratus wi-th a stationary bed o~ a granulated catalyst or with a liqui-~ied bed o~ a small-size catalyst the s-tarting hydrocarbon feed is supplied alon~ with t~e diluent at the above-mentio-ned temperature and a contact time o~ the ~as stream and the catalyst is varied within the range o~ ~rom 0.01 to 100 mi~0 ~he reaction products are cooled and a~ter sepa*ation o~ -the diluent are delivered to the fractionation system~ Duration of passing the ~eed through the apparatus ranges from 15 sec to 20 min. A~ter disco~ti~uation of the ~eed supply, the ap-paratus is purged with an inert gas to xemove vapouls o~
h~drocarbons a~d then the spent catal~st is rege~erated at a tempera-turs within the rang~ o~ ~rom 400 to 700C ~or a pe-riod o~ ~rom ~5 seconds to 20 minutesD ~he re~neration is effected in a current of a~ oxygen-cont~ining gas such as air till restoratio~ o~ the cataly~t activity. ~o remove oxyge~ ~rom the apparatus a~ter disco~tLnua-tion o~ the rege-neration~ the catalyst is purged with steam or and iner~ gas and ~eed is again admissed into the apparatus ~or the ~oll~w i~g cycle.
: ~o prolong the service li~e o~ the catalyst under the conditlons o~ dehydroge~atio~ it is possible to i~troduce, .

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~ 3 simultan~ously ~vith the feed9 a s~all amount of ~xygen (not more -than 0.1 mole per o~e mole o~ the startin~r hydrocarbo~
feed).
Conti~uous opera-tion is obtained as a result of co~bi-~atio~, in o~e pla~t, of -two or more reactors, wherein the stages of dehydrogenation7 purging and regeneration are time--shi~tedO
It is most advisable to pex~orm the process according -to the present in~ention in sys-tems with transportation o~
the catalyst, ~or example in a system of two ~`luidized-bed apparatus wi-th a small-si~e catalyst~ In the first apparatus dehydrogenation is effected under the above-described co~di-tions. ~he sp~t catalyst via a tra~sportatio~ li~e is con-tinuously ~ed to the oxidizing regeneration i~to the second apparatus (re~enerator). The regenerated catalyst is recycled back to the dehydroganatio~ zone. During transportation o~
the catalyst, it is subjected to pur~ing ~or the removal of hydrocarbons and ox~ge~. Bppara-tus dimensions the catalyst leYel thsrein, circulation ratio o~ the catalyst are determi-ned by the plant capacity, composition of ths catalyst and a~ optimal degree of the catal~st oxidation.
However, with the account o~ -the fact that irl many cas-es the catalyst possesses the highest selectivity and acti-vity only within ver~ short periods o~ tim~ and it is eco~o mically efficient to use a catAlys-t with a lowered conte~t of active componen~s capable o~ carrying sm~ll amounts o~

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' ' ' ~3 ~ 16 -oxygen~ ~he mos~ suitable ~or ~omo!ercial implementation is the ~ollowing technological embodi~ent o~ the pxocess accor-ding to ~he present invention.
Eleated hydrocarbon ~eed ~apours along with said dilu-e~ts are ~upplled i~to the bot-to~ section of a lift-reactor, whereinto through a special means o~ the i~jector type a smali-size catalyst is ~ed from the regenerator. ~he cata-lyst is co~veyed by the stream o~ ~eed~ diluen-t and the reaction products a~d sepaxated therefrom i~ a sepaxator means. ~'he reaction products are ~urther puri~ied -to remove the entrained catalys-t particles, whexeafter they are cooled, separated Irom the diluen-t and ~r~her delivered to the se-paration system, wherefrom the unreacted feed and intermedi ate reaction products are recycled to the reactor.
The catalyst 9 af-ter purging~-o~ the hydrocarbons 3 iS
passed rro~ the separator, cyclones a~d fil~ers to the rege nerator unit with a ~luidized bed o~ the catalyst~ whereinto a~ oxygen-containing gas, e.g. air9 is ~d too. ~fter anoth-er purging, the regenerated ca-talyst is recycled into the bottom part o~ the reactor~ ~or pla~ts with a higher capaci-ty, i-t is possible to combine in one sys-tem sevexal li~t--reactors with a comm~ regenerator and a commo~ system o~ ~
separatio~ of the reaction products~
llhe time o~ co~t~ct o~ the ~ed and the catalyst is varied within the range o~ from 0.5 to 15 seco~ds; residence time o~ the catalyst in the li~t-reactor and separatox does not exceed 2 - 3 minutes.

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~ lhe proc~ss o~ d~hydroge~tion according to the present inven-~ion undar the above-me~tioned conditions makes it possible to provide for pla~ts with a higher unit output ~vith a high yield of the desirecl products and increased se-lectivity relati~e thexeto. O~i~Lg to con-ti~uous scheme of the process and constant composition o~ the r~action products9 separation -th~reo~ is facilitated along with reduc-tio~ of losses of the products at this stage; temperature co~trol and utilization of hea-t of the o~f-streams become more simpleO
At the s~ne time, this mode of de~ydrogenatio~ imposes Quite sever~ r~quir~ments on activity~ sele~tiviby a~d weax--resistance o~ the catalyst. Preparation o~ the catalyst em-ployed in the process according to the present invention is e~ected in the following ma~er.
At ~irst 9 the carrier is prepared. ~o this e~d, 96-99%
by weigrht o~ ~inely di~ided quartz sand are mixed with 1-~%
by weight o~ bicarbonate (carbonate) of sodium, potassium or lithium, or 50-95% by weight o~ mag~ia are mI~ed with 5-50% b~ weight of ~itania, or 70 to 95~0 4y weight o~ magne-sia are mixed with 5 to 30% by weight of alumi~a (alumi~ium hydroxide)~ '~he resulting miæture is granulated to give pel-lets o~ required dimensions a~d shape. ~ho granulation is per~rrmed with the addition of water, aqueous sol~tions o~
poly~inyl alcohol, dextri~e, carboxymethylcelluloso using tabletti~g machines~ extrusio~-type or adhesio~ granulators of various des~g~s~ '~o pr~pare a small-size cRtalgst) a " . . . . , : .

: ~, ~,' ~ :, .

~3 spray drying is used alo~ with adhesion-type gra~ula-~ors~
~he resulting gra~ules are ~ried a-t a temperabure ~ithin the range of ~rom 60 to 150C a~d calci~ation -thereof is e~ect-ed at a temperature o~ ~rom 900 to 1,300C for a period o~
~rom 30 minutes to 6 hoursg ~he calcination duration and temperatuxe are selected depending on the composi-tio~ o~ the starting charged a~d rsquirements imposed o~ the resulting carrier~
Duxing calcinatio~ o~ granules silicates o~ alkali me-tals or tita~ates a~d alumi~a-tes o~ magnesium are formed which ens~e a durable bondin~ o~ particles o~ silica or mag-~sia in the caxriex granules. At a temperature o~ above 800C a phase transitio~ o~ ~ -quartæ to crystoballite is observed.
~ he calcined granules of the porous quartæ carrier are modi~ied by impregnation with a~ aqueous solution o~ mag~e-siu~ ~itrate. ~he solution excess is removed by deca~ation or evapoxation. Then the carrier is calci~e~ at a temperatu-re within the range o~ ~rom 300 to 500C to decompose mag~e-sium nitrate~
The thus-prepared carriers have a high mechanical strength, increased heat~resistance. ~heir abrasion resist- -ance is higher than ~hat o~ alumosilicate. Speci~ic surface area o~ the carriers, depending on the composition and pre-paration condition~ is varied withi~ the range o~ from 2 to 15 m2/g~ porosity is equal to 002 - 0.4 cm3/cm3.

.

, ~ . ,,, . , ,, ,, . :.

., - , "
. . . ' : -, : ' : . , , .:: : ~ .
:. : . .: . , .. : , , , ~ 19 -The -thus-prepared lot o~ the carrier o~ the re~uixed ~ractional compositio~ is poured with a concentxated solu~
tion of ammo~ium mol~bdate. To ensure a more uniform impre~-nation o~ granules~ it is d~sirable to set the vessel Y~ith the carrier under vacuum prior -to pouring the solutio~ the-reinto Due to the interaction between a~mo~iu~ molybda-te and magnesia ~he suspension is heated-up and ammonia is li berated and evacuated ~rom the vessel. ~fter rasidence in the reac-tor ~or 0.5 - 5 hours, water is evaporated from the suspension at a temperature within the ran~e o~ Y`rom 60 to 180C. ~o avoid aggregation, the impregnatio~ and evapora--tion are carried out under continuous or periodic stirri~g of the suspension. ~he ~aporizakion process can be intensi-fied by setting the vessel under vacuum~ ~or this reason pre-paration o~ the catal~st should be pre~erably e~ected in hermetically sealed heated apparatus provided wi-th a low--speed stirrer ~or example in Z-shaped mixers. Completion o~
the process is determined by a rapid growth o~ temperatuxe in the apparatus.
o prepare a polycomponent catalyst by this method, the mass resulting ~rom o~aporatio~ is poured with an aqueous solution o~ cobalt, nickel, iron or ma~ganese nitrate.
Impregnation and e~aporation are e~ected as described abo~e~
Impre~rna~ion with e~aporation makes i-t possible to p~e-pare a catalyst o~ a prede-termined composition and lower con-sumptio~ o~ the active componënts ~or the catalyst preparation~

.
;

. .

~ 20 To prep~re a polycomponent ca-talyst with a mox~ uni-form distribution of -the active phase ~ithin the volu~e of granules a~d with a better conlac-t among t~e compo~e~ts, application .is effected Irom dllu-ted solutions o~ salts al terrlatively~ i.e. repeatin~ operations o~ impregnation wi~h each salt and a subse~uent evaporation ~or 3 to 12 timesO
Thus, in the preparation of a cobalt~molybdenum catalystl the c~xrier is poured with a solution of c~monium molybda-te;
water is evaporated from the suspension ~nd then poured with a solution o~ cobalt nitrate and -the susperlsio~ is again evaporated, whereafter Impregnatiorl with a solution of ammonium molybdate is ef~ec-ted and so on, th~ p~ocedure is repeated ~or 3 to 12 times. As a result of a more u~i~orm distribution o~ the acti~e phase within the volume of granu-les and higher degree o~ eness thereof, the catalyst ac-tivity is substantially increased, i.e. by 20 to 50%. l'he same effect may be achieve ~ n the ~ollowing manneri After impregnation of t~e carrier with a solution o~ ammonium molybdate ? evaporation~ treatment with solukions o~ nitrates of cobalt, nickel, iron or man~anese and a subsequent eYapo-ration o~ water from the su~pension, the resulting mass is treated with aqueous solutions of ammonia, amin~s or amino-alcohols. ~hen evaporation of water is repeated with subse-quent calcination of the mass under the above~me~tio~ed co~-ditio~s. Upon treatment with ammo~ia, amines or aminoalcoho~s , .
, '.. ': '' '. ' . '' ' ' : '. . . ' .,:
.. . . . . .

., , . . : ., ~ . .

duri~g the prep~ration of polycomponent catal~st3) e.~. co balt-~olybdeIlum ca~alyst, there occurs combina-tion of the active components to complexes containing cations Co2~ ancl Mo6~ as well as 1~I4 and OH groups which ensures a more uni-~orm distxibution o~ t~e components o~ the active phase and increases its finenes~ For this reason~ in suc~ catalysts no ~ree o~ides of molybdenum ancl cobalt are ~ound (i-eO the process o~ the preparation o~ the ca-talyst goes to its com-pletion).
All o~her conditions being e~ualJ -the yield o~ divi~yl and selectivity on a catalyst trea-ted~ durinO its prepara~
tion, with monoethanolami~e is about 2 -timss as ~igh as those of a similar catalys-t prepared by a single-applica-tion method.
In accordance with the process of the presen-t in~0~ion after applicatio~ o~ the active components and e~aporatio~
o~ water, ~he clried mass is calcined for the ~inal ~ormation o~ the catalyst ~or 0~5 to 25 hours (pre~erably from 2 to 6 hours) at a temperature within the ran~e of from 350 to 700C (preferably ~rom 450 to 600C). ~o avoid reduction of the catalyst, calcination is conducted in an inert or oxidiz-ing medium. ~o preven~ variations of the fractional composi-tio~ of the small-siza catalyst due -to sintering of its par-ticles, it is advisable to perfDrm calci~ation o~ said cata-lyst in a fluiclized bed in a ciurrsnt of an inert o~ an oxygen--contiaining gaic;.

, .. .. ~ . . . . .

- , , ,~ - . . .

~44f '~
- ~2 -For a b~tter underst~nding o~ -the 1ires~-t inv~ntion some specific e~amples illustratin~ -tha process ~or prodllc~
ing unsat-~a-ted hydrocarbons ~re given ~e~einbelow.

A carriqr is prepared in the followin~ ~a~ner. 95% by weight of mag~esia are mi~ed with 5% by weib~ht o~` titania.
~he resulting mix~ure i5 plas-tl~ied b~J addin~ a 2~ solution o~ polyvinyl alcohol and by -the rubbin~ method gra~ules o~`
a size o~ from 0.1 to 0~3 mm are prepared. ~he gxanules are dried for two hours at a -temperature within -the ran~e of' from 80 to 90C a~d calcined in a mu~fle ~ux~ace for one hour at the temperat~re of 650C~
To prepare the catalystO -there are mi~ed a solution o~
24.3 g o~ ammonium mol~bdate in 100 ml o~ distilled water and 70~0 g o~ the carrier prepared as above (~mpreg~ation).
As a result, there is obtained a suspension~ where~rom water is remo~ed by evaporation with a progressive grow-th o~ -tem- -perature up ~o 150C. ~he resulting mass is subjected to calci~ation i~ a current o~ air at a temperature o~ ~ro~
590 to ~00C ~or the period of 25 ~ours. ~ catalyst is thus produced having the following compositio~: ~oO3 22% by weight9 MgO 74.1% b~ weight, TiO2 3~9% by weight~ Specific sur~ace area of the catal~st is 65 m2~g~
I~to a r~ackor with a fluidized bed of the thus-prepar-ed catalyst (fractio~ with a par-ticle s~ze of from O.l to 0.~ mm~ at -th~ temperature 590C there are alter~atively fed , . . . . .
- ~ . . ' , .
' ; : ~ ,' ', ' . ~ ' . ~ . . .

. .

n-butane with argon, and air~ Molar ratj~o betwee~ ~-butane and argon is equal to 1:10. Space velocit~ of the supply is ~50 hr 1 ~nd the supply duration is 0.5 minutes. ~he cotal dura-tion o~ the process is 35 hoursO
Conversion of n-butane is 4892%, the yield o~ butadiene is 36.2% wi-th selectivity relative thereto of 75~1~o and re-lative to -the total o~ butylenes-butadiene 85~4%~
Example 2 ~ o prepare a catalyst a solu-tio~ o~ 10.0 g o~ ammoniu~
molybdate i~ 20 ml of dis-tilled water is mixed with 16.0 g of the carrier prepared in the foregoin~r E~arGple lo '~he re-sultin~ suspension is subjected to evaporatio~ at a tempera-ture wi-thin the range o~ from 80 to 130C. '~ha calcina~-ion is ef~ected at a -temperature of ~rom 680 to 700C in the atmosphere o~ nitrogen ~Qr 0~5 hourO A catalyst is thus pro-duced and its composition is the ~ollowing~ MoO~ 35~0 b~
weight9 MgO 61.7% by weight, iO2 3.3% by weigh'c~ Speci~ic surface area of che catalyst is 41~3 m2/g~
~ nto a reactor with a ~luidized bed of this catalyst at -the temperature of 550C there are alter~atively ~ed n--butans in a mixture wi-th ar~on~ and air. Molar ratio betw~-en n-butane and argon is 1:13. Space velocity o~ -the feed supply is 105 hr 1, duratio~ of the supply is 0.5 mi~ ~pace velocity of the air supply is 1,350 hr 1 and duration o~ the supply is 0~5 mLn. ~he t~tal dura-tio~ o~ the process is 5 ~ours.

~: : ~ . . .

-- 2~L~ _ Conversion o~ n butane is 30.2%, the yield of bu-tadie~e is 23~2,;~ with selectivity relative thereto o~ 764~ a~d re-lative to the to-tal o~ butylenes-butadie~e o~ 85.8%.
~xample ~
'l'o prepare a ca~alyst a solution of 24.3 g o~ ~monium molybda-te in 100 ml o~` distilled, wa-t~r is mixed with 70~0 g of magnesium-aluminium carrier consistin~ o~ 70% by wei~h-t of mag~esia and 30% by weight o~ alumi~a~ (Preparation o~
the carrier is e~ected in a ma~ner similar to that descri bed in the ~ore~oi~g Exa~ple 1). ~he sta~es o~ evaporation and calci~atio~ are conducted under the conditions o~ Ex~n-ple 1.
A catalyst is prepared having -the .following composi-tion:
~oO3 2101% by wei~ht, ~gO 55.3% by weight, A1203 23.6% by wei~ht. Speci~ic sur~ace area of the catalyst is 16~3 m2/g.
Into a reactor with a ~luidized bed o~ ~he catalyst prepared as above at the tempera-ture o~ 595C there are al-ternatively added ~-buta~e in a mixture with steam, a~d air.
Molar ra-tio be~wee~ n-buta~e and steam is 1:30. Space velo-city o~ the mi~ture supply is 40 hr 1 a~d the supply duration is 0.5 min. Space velocity of the air supply is 450 hr 1 a~d the supply duration is 005 min. ~he total duration o~ ths process is 4 ho~rsO
;~ Conversio~ of n-buta~e is 24.0~v~ the yield of butadiene is 11.0% with sele¢tivity relative thereto o~ 45~9% and rela-tive to the total o~ butyla~es-butadiene o~ 5103%.

~ ~ .
:

. ~ . . j . ~ ................ .

.

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~ 25 ~

Use is made o~ -the catalyst described in the ~oregoi~g Example 1~ ~he dehydrogenation process is per~ormed u~der the conditions o~ Example 1. As -the starting ~eed use is made o~ n-butylenes (the conten.t of n-bu-tylenes is 99~8% b~
volume), and o~ steam as a ~ehicle. ~he total duration of tha pxocess is 38 hoursO
Conversion o~ butylene~ is 85.1%~ the -~ield o~ bu-tadie-ne is 79.5% with selectivity rela-tive -to butadie~e o~ 9~.5%.

~ o prepare a catalyst, use is made o~ 100 g o~ a car-rier with a particle size o~ Ool ~ O~ mm consisting of 75~O
by wei~h-t of magnesia and 25% by wei~rh-t of'-titania and cal-cined at the temperature o~ l,000C~ a solution o~ 32.9 g o~
cobalt nitrate in 400 ml o~ distilled water (solutio~ ~) and a solutio~ o~ 20.0 g o~ ammonium molybdate in 400 ml o~ di-stilled water (solu-tion B).
Preparation o~ the catalys-t.is e~ected by alternative t~o-s-tep application o~ the catalyst components (cobalt and ~ molybdenum) according to the ~ollowing scheme:
; l-st step: solution A is mixed with the carrier and water is removed from the resulting suspension by evapora-tion at a te~perature within the ra~ge o~ ~rom 80 to 120C;

2-nd s.~ep:.the mass obtained in the ~irst stage is mixed with solutioll B and water is removed from th~ result-ing suspensio~ by evaporation at a te~perature wi-thi~ the range of from 80 to 150C.

.
. .: - .. . .

~Ll~L4~3 The resul-ting mass is calcined a-t the temperature o~
550C in a suspended bed in the stream o~ air for 5 hours.
A catalyst o~ the ~ollowing composi-tion is obtained:
MgO 66.550 by weight, ~iO2 22.2% by wei~h-t, CoO ~.0~0 by weigh-t, MoO3 7.3~ by weight.
Specific surface area o~ the catalyst is 12.3 m2/g.
~he dehydrogenation process on the thus-prepared catalyst is co~ducted under the co~ditions described in the ~ore-~oing Example 2.
Conversion o~ n-butane is 25.0%, the yield o~ buta-diene is 6.1% with selectivity rela-tive thexeto o~ 24~2%
and relative to th~ total of butylenes-butadiene o~ 37.5%.

A catalyst is prepared ~ollow~ng the procedure descr-ibed i~ -ths ~oregoing E~ample 5~ e~cept that ~pplication o~
the active componen-ts (cobalt and molybdenum) is e~ected in 4 and 12 sta~es according to the following two schemes:
l-st scheme: , In the l-st stage 200 ml o~ solution A are mLxed with the carrier a~d water is remo~ed ~rom the resulti~g suspen-sion by evaporation at a tempsrature within the range o~
~rom 80 to 120C;
I~ the second stage the mass resulting ~rom the ~-st stage is mi~ed with 200 ml of solution B a~d wa-ter is remo-ved from the r~sulti~g suspensio;~L b~ evaporation o~ ~rom 80 to }50C;

' , - : . . :
': . .:
. . . . . ..

~:' - , , , 1~144Q3 27 _ I:~ the 3-rd s tage the ~nass resulting ~rom th0 2-nd s-tage is added vlith the remaining portion o~ solu-tion A
and water is evaporated at a tem~erature within th~ ran~e o~ ~rom 80 to 120C7 In the 4~th stage the mass resulting from the 3-d stage is added with the remai~ing portio~ o~ solution B a~d water is removed by evapora-tion at a temperature of ~rom ~0 to 150C.
'~he mass obtai~ed in the ~ourth stage is calcined at the t~mperature o~ 550C ~or 5 hour~ in a stream o~ air.
2-nd sch~me:
The numb~r o~ stages is 12; L~ each uneve~ stage there are added 67 ml of solution ~, in each even stage there are added 67 ml o~ solution B~ I~ each stage wa~er is removed ~rom the resulting suspension by way o~` evaporation and a~ter the ~inal stage the resulting mass is subjected to calcination at the temperature of 550C f~r 5 hours in a stream o~ air.
~Characteristics o~ the catalysts prepared in the l-st ;and 2-nd schemes as well as the results o~ dehydroge~ation processes carried out under the conditions o~ E~ample 2 o~
the catalysts prepared as described hereinbe~ore ~re shown in t~e Pollowi~g Table 1.

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A catalyst is prepared ~ollowi~ the procedure descri-bed in the ~oregoi~g ~xample 5~ except that z~ter applica-tion o~ the active componen-ts the resulting ma~s prior to calcination is treated with an a~u~ous solution o~ ~nonia, an amin~ or aminoalcohol. From the resultin~r suspensio~
water is removed at a temperature withln the ra~e o~ ~rom 60 to 180C and the thus-obtai~ed mass is calci~ed at a ternperature within the range of from 540 to 560C ~or 5 hours in the air atmosphere.
Charac-teristics o~ the thus-prepared catalyst~ as well as the resul-ts o~ the dehydro~enation process p~r~ormed under the condi-tio~s o~ Example 2 hereinbe~ore using the catalyst prspared as above are given in '~able 2.

Preparation o~ a catalys-t is carried out following the procedure described in the ~oregoing ~xample 6 (2-~d scheme)~ e~cept that i~s~ead of the solu-tion of cobalt ni~
trate for the preparation o~ the catal~st use is made of one o~ ths ~ollowi~g solutions:
(1) solution of 6302 g Of nickel nitrate in 400 ml of distilled water;
(2) solution o~ 74.4 g o~ iron nitrate in 400 ml of dis-tilled wal;er;

(3) sol~tjion of 62.4 g of ma~ganese nitrate in 400 ml o~ distilled waterO

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~ 3 I~ all cases use is made of a solu-tion o~ 40~0 g o~
ammonium molybdate in 400 g distilled watex.
~ he dehydrogenation process is conduc-ted uader the con-di-tio~s described Ln ~Xample 2 hereinbefore. Charac-terist-ics of the catalysts and res~ ts o~ -the dehydrogenatio~
process are shown i~ the ~ollowing Table 3~

Preparation o~ the catalyst is effected ~ollowing the procedure described in Example 6 hereinbe~ore (2-~d sche-me)~ e~cept that the carrier employed for the preparation of the catalyst is calcined at the temperature of 1,200C;
after impregnation and dryi~g the carrier is agai~ calci-ned at the temperature of 350Co ~ he ~inal catalyst has the following compositio~: CoO4.8% by weight? MoO3 903% by weigh-t, ~gO 64.5% by ~Jei~ht~
i2 21,~% by weight~
Speci~ic sur~ace area o~ tha catalyst is 15.0 m2/g, ~ he process o~ dehydrogenation o~ n-butane i5 C onduct-ed conti~uously ~or 1,000 hours~ ~he data are gi~en i~
~able ~ hereinbelow~
Upon addition of oxygen to -the starti~g feed in the stage of dehydrogenation in the amount of 0~09 mol/mol of n-butane under the conditions of the ~oregoi~g Example 1, co~version o~ n-butan~ is e~ual to 40~8%~ the yield of bu-tadiene is 26~4~o with the salectivity relative thereto o~
64.7% and r~latiYe to the total o~ butylenes-butadiene o~
73.0Yo. -: ~::

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-- 3'.~ ~
xclmple 10 '~`he d~hydrogenation process i.s carried out using the catalys-t described in the ~oregoing Example 9~ ~s the s-tart-ing ~eed use is ~ade o~ ethylbenzene. ~he data o~tained are given in -the following ~able 59 Upon addition of oxygen to the st~rting ~eed in -the s-tage o~ dehydrogenatio~ in -the amoun-t o~ 0.09 mol/mol o~
C6Elo undor the conditions described in ~x~nple 3 hereinbe-~ore, conversion o~ ethylbenzene is equal to 97.~%, the yield o~ styr~ne is 85~4% with the select.ivity relative th~reto of 87.8%~
~xamp,~le 11 ~ he dehydrogenation process is co~ducted usi~ -the ca-talyst described in ~xample 9 hereinaboveO As the starti~g feed use is made of ethyltoluene. ~he process i~ carried out at the temperat~re o~ 5~0C 7 space velocity Qf the supply o~
ethyltoluene o~ 40 ~r 1~ molar xatio between eth~ltolue~e and argo~ equal to 1:9, dehydrogenatio~ duration of 1 minute, space velocity o~ air supply at th~ stage o~ regeneration o~
490 hr 1, re~a~eratio~ duratio~ of 1.0 minute~ Co~version o~
eth~ltoluene is 81~1%, the ~ield o~ vi~yltolue~e is 70.6%
with the selQctivit~ relative thereto o~ 87.3%.
~ ' The dehydroge~ation process is co~ducted using the ca-talyst described in the ~oregoing Example 9~ ~s the starting ~eed use is made o~ iso-pentane with the purity o~ 98% by ~, .

.
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~ 36 wei~h-t~ ~he process is conduc-ted at the -te~perature o~
550C3 space veloci~y of iso-p~ntane supply of 95 hr 19 molar ratio bet~Jeen iso-penta~e and argon equal to 1~13, dehydrogenation duration o~ 0~5 minute; space ~elocit~ o~
the air supply o~ 50 hr 1 at -the stage o~ regeneratio~3 duration of the rege~era-tion is 0.5 ~i~uteO Con~ersion o~
iso-pen-tane is 28.9%, yield o~ isoprene is ~.2% with the selectivity relative -t~ereto o~ 14.5% and relative to t~e total o~ isoamylene-isopre~e o~ 22~5~o~
xa~n~le 1~
'l`he dehydro~enatio~ process is conducted usin~ the catalyst described i~ ~xample 9 hereinbe~oreO ~s the start-ing ~ead use is made o~ the isopen-tane-isoamylene fraction ha~ing the ~ollowing compositio~, per ce~t by weight: 2-me-thylbutene-l 1.56; 2-~ethylbutene 2 49.29; 2-meth~lbu-tene-3 30.35~ isopentane 8.28; ~-pentane 4000, ~-pe~-tenes 3~92;
; isopre~e 2060.
: ~he process is conducted at -the temperature o~ 545C
~ space rate o~ the ~eed supply o~ ~1 hr~1, molar ratio o~
i-C5 to steam e~ual to 1:7, dehydrogenation duration of 0.5 minute~ space velocity o~ the air su~ply in the regene ration stage o~ 280 hr-19 re~enera-tion time ~f 0,5 minute.
Convarsion of the isopentane-isoam~lene fraction is 59~4%, the yield of isoprene is 41~4~o with the selectivity relative .~ thereto of 69.7%.
.

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.

- ~7 -x~llple 14 Preparation of the catalyst is per~ormed ~ollo~Jing the procedure described in the ~oregoing Ex~nple 6 (2-nd scheme).
~he carrier employed ~or the catalys-t preparation consis-ts o~ 50% by weight of magnesia and 50~0 by weight o~ titania;
the catalys-t carrier is calcined at the temperatur~ of A catalyst is thus obtained with the ~ollowing compo~i--tion: MgO 4302~o by weight, ~iO2 43.1% by weight~ CoO 4.'7%
b~ weight, MoO3 9.0% by weight.
Specific sur~ace area of the catalyst is 1~9 m2/~.
~ he dehydrogenation process usi~g the resulting cata-lyst is conducted under the conditions of ~xample 2 herein-be~ore.
Conversion o~ n-butane is 1509%, the yield o~ butadie-ne is 6.5% with -the selectivity relative to b~tadiene of 40.5% and rela-tive to the total o~ butyle~es butadiene o~
~4.7%0 Exam~
Preparatio~ o~ the catalyst is e~fected followi~g the procedure described in Example 5 hereinbefore, except that the carrier employed for the catalyst preparation consists 0~ 95YO by weight of magnesia and 5% by w~ight o~ alumina a~d the removal of water ~rom the suspension is per~ormed under vacuum at a tsmperature wlt~in the range o~ from 60 .~ .

.. .: , :

..... . ., ~. . . -to 70PC. ~ ca-talyst is thus prepared whlch has the follow-ing composition~ MgO 78.8% by wei~ht, A12O3 4.1% by ~^7eight, CoO 6~2~ b~ wei~ht, MoO310.9% bv ~eight~

Spec.ific surface area of the catalyst is 17.6m2/g.

Dehydrogenation process ~ith the use of the resulting catalyst is carried out under the conditions of the fore-goina Example 2.

Conversion of n-butane is 24.3%, the yield of but-adiene is 5.6% with the selectivity :relative thereto of 23.1%
and rela-tive -to the total of butylenes-butadiene of 29.7%.

Example 16 As a carrier for the prepara-tion of a catalyst use is made of a porous crystalline silica (fraction with the par-ticle size of O.l to 0.3 mm) calcined at 1100C, modified with alumina. The modification of silica is conducted by ~: impregnation thereof with an a~ueous solution of magnesium nitrate, followed by the removal of excess solution, drying at a temperature within the range of from 110 to 120C and calcination at a temperature of from 370 to 400C. The con-tent of magnesia on silica is varied by appropriately adjust-ing concentrations of the impregnating solution. The result-ing carriers have the following characteristics depending on the content of magnesia:

.

.. .. . . . ..

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Magnesia content as Specific Bulk vJei~ht, No.calculated for the sur~ace 3 carrier7 wto% area, m~/g ~r/

1 1.0 0.6 0~80 2 1208 706 0.92 3 20.0 801 0.94 To prepare the catalyst7 a solution o~ 24.0 g a~monium molybdate in 500 ml of distilled wa-ter i5 mixed with 100 g of the carrier. From the resulting suspe~sion water is re-moved by evaporation at a temperature within the ran$e o~
from 80 to 150Co ~he~ the resulting mass is mix~d with a solutien of 39.5 g of cobalt nitra-te in 500 ml o~ distilled water with 100 g of th~ carrier. From the resulti~g suspen-sion water is removed by evapora-tio~ at a temperature of f~om 80 to 120C and ~he thus-produced mass is calcined at a temperatura of from 540 to 560C~ ~he resulting catalysts have the follo~i~g characteristics depending on the starting carrier employed Conte~t of the active com~ Catal~st Catalyst No po~e~ts as calculated ~or specific bul~ ~eight, the catal~t, wt.% surface~ g/cm~
CoO ~0area9 m /g :, 1 7.~ 8.8 1.~ 0O9 2 4.6 8.7 7.6 1~0 3 5.8 5~8 8~2 1~1 .
.:
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-- ~o -'~he process of dehydrogena-tion is carxied ou-t in a reac~or similar to -tha~ described in -the foregoirlg ~xa~ple 1. Usi~g the catalyst No.l (see the above ~able), t~ough the reactor at the temperature o~ 570C i-pe~ta~e i5 passed at the space rate o~ 105 hr 1 a-t the molax ratio o~ i-pen-tane to helium of 1:13. r~he duxation o~ i-pentane supply is 1.0 minute. Space velocity o~ the air supply in the re~ene-ra-tion stag~e is 17350 hr 1 with the supply duratio~ o~ 1.0 mi~ute. '~he total process time is 5 ~ours.
Conversio~ o~ i-pe~tane is 7~7%9 the yield o~ isoprens is 3.6% with the selectivit~ relat.ive -thereto o~ 46~8~o a~d xelative to th~ sum o~ isoamylenes-isoprene of 58.6%.
Usin~ the catalyst No.2, through the reactor at the temperatura o~ 550C n-butane is passed at the space veloci-ty of 80 hr 1 at the molar ratio between ~-butane and the diluent o~ 1:15. As the dilue~t use is made o~ a mixture o~
80% by weight of steam and 20% by weight o~ nitrogenO ~he duration o~ n-butane supply is 1 sec. Space velocity o~ the air supply is 19200 hr 1 with the supply duratio~ o~ 0.5 mi-nute. ~he total duratio~ o~ the procsss is 0.5 hourO
Converqion o~ ~-bu~ane is 17.8%, the yield o~ butadie-ne is 8.7% with the selec-tivity relative thereto o~ 48.9%
a~d relative to the total ol butylenes-butadiens o~ 54.3%.
Using the ca-talyst ~0-~7 through the react.ar at the temperature o~ 560C with ~he space velocity of 90 hr 1 a . .

. - , . , - - - . , . - : .- . , . . . ... .. ~. .
.
.

- L~ 3 mixture o~ hydrocarbons is paased consis-ting of 21~1~o by weight o~ ~iethyltoluene, 6506% by weight o~ ethyltoluene7 ll~9~o by weigh-t of ethylbenzene and 1.4% by weight of tolue-ne. ~he molar ratio be-tween the hydrocarbon.~eed and nitro-gen is equal to 1:9. D~ration o~ the ~eed supply is 1 minu~
te. Space veloci-ty o~ tha air supply i~ the stage o~ rege-neration is 900 hr 17 supply duration is 1 minute. r~he to-tal duration o~ the process is one hour.
Conversion o~ ethyltoluene is 53.2%, the yield o~
vinyltoluene is 42.6% with the selectivity relative there-to o~ 80.1%. ~he yield o~ divinyltoluene is 2~1~o~ the yield of vinylethyltolue~e is 1~6%9 the yield o~ styre~e is 12.6% as calculated ~or the total star~ing hydrocarbon ~eed.

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Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for producing unsaturated hydrocarbons comprising contacting compounds selected from the group consisting of paraffins, monoolefins and alkylaromatic hydro-carbons at a temperature in the range of from 400 to 700°C
in the presence of an inert component selected from the group consisting of an inert gas and steam, with a catalyst comprising a carrier having deposited thereon an oxide compound of moly-bdenum in an amount of from 5 to 35% by weight of the catalyst, said carrier being selected from the group consisting of a granulated porous crystalline silica modified with magnesia in magnesium-titanium carrier consisting of 50 to 95% by weight of MgO and 50 to 5% by weight of TiO2, and a granulated magnesium-aluminium carrier consisting of 70 to 95% by weight of MgO and 5 to 30% by weight of Al2O3; and passing an oxygen-containing gas through the spent catalyst at a temperature within the range of from 400 to 700°C to restore catalytic activity of the catalyst.

2. A process as claimed in claim 1, wherein the catalyst has compounds selected from the group of oxide compounds of cobalt, nickel, iron and manganese also deposited on the carrier in an amount of from 3.7 to 15% by weight of the catalyst.

3. A process as claimed in Claim 1, wherein said contacting of the compounds selected from the group consisting of paraffins, monoolefins and alkylaromatic hydrocarbons with the catalyst is effected in the presence of oxygen in an amount of up to 0.1 mole per one mole of the hydrocarbon feed.

4. A process as claimed in Claim 1, wherein the catalyst is prepared by impregnation of the carrier with an aqueous solution of ammonium molybdate to obtain a suspension, wherefrom water is removed by evaporation and the resulting mass is calcined at a temperature in the range of from 350 to 700°C in a medium selected from the group consisting of an inert medium and an oxidizing medium.

5. A process as claimed in Claim 4, wherein the removal of water from the suspension by evaporation is effected under vacuum.

6. A process as claimed in Claim 4, wherein calcination of the resulting mass is effected in a fluidized bed.

7. A process as claimed in Claim 4, wherein prior to calcination the carrier is also impregnated with an aqueous solution of a nitrate selected from the group of a metal consisting of cobalt, nickel, iron and manganese, said impreg-nation and impregnation with an aqueous solution of ammonium molybdate being effected in any order and between said two impregnations water is removed from the resulting suspension by evaporation.

8. A process as claimed in Claim 7, wherein said impregnation with aqueous solutions of salts and removal of water by evaporation is repeated of from 3 to 12 times.

9. A process as claimed in claim 7, wherein the result-ing mass of the carrier, impregnated with aqueous solutions of ammonium molybdate and a nitrate salt and dried is treated, prior to calcination, with an aqueous solution selected from the group of a nitrogen-containing compound consisting of ammonia, amines and aminoalcohols, followed by the removal of water by evaporation.

10. A process as claimed in claim 9, wherein the aqueous solution of an amine is an aqueous solution of a compound selected from the groups consisting of methylamine and triethyl-amine.

11. A process as claimed in Claim 9, wherein the aqueous solution of an aminoalcohol is a solution of a compound selected from a group consisting of monoethanolamine and triethanolamine.