The method of producing styrene
(57) Abstract:The invention relates to catalytic processes, in particular the obtaining of styrene by the catalytic dehydrogenas ethylbenzene on iron oxide catalysts at a temperature of 560 - 640oC in the presence of water vapor, followed by separation of styrene from the products of dehydrogenation of ethylbenzene (furnace oil) by multistage distillation with sequential allocation benzatropine faction, return ethylbenzene and styrene-rectified. The invention consists in that, to increase the conversion of ethylbenzene under dehydrogenation of ethylbenzene on iron oxide catalyst, the content of styrene in etilbenzene the charge coming into the dehydrogenation reactor, is maintained at a level no higher than about 0.15 wt.%, it allows you to increase the conversion of ethylbenzene with 62,9 to 67.9 wt.%. The invention relates to the field of catalytic processes, namely the obtaining of styrene by catalytic dehydrogenation of ethylbenzene, and can be used in the petrochemical industry.Known methods for producing styrene by catalytic dehydrogenation of ethylbenzene on iron oxide catalysts at temperatures of benzene by multistage distillation with sequential allocation benzatropine faction, return of ethylbenzene and styrene-rectified. CBM product of the column selection styrene-rectified subjected to additional distillation with return of distilled styrene in the column selection styrene-rectified.P. Kirpichnikov, A. and others "Album of technological schemes of the main production of the synthetic rubber industry", HP, "Chemistry", 1980, S. 100.Oil, gas and petrochemicals abroad, 1991, 8, S. 100 - 102.In known methods for producing styrene content of the styrene in return ethylbenzene reaches up to 1.5 wt.%, which results when it is mixed with fresh ethylbenzene to styrene content in etilbenzene the charge coming into the dehydrogenation reactor, in the range of 0.4 - 0.4 wt.%. The conversion of ethylbenzene in this way is usually not more than 60 wt.%
U.S. patent N 3326996, CL 260-669, publ. 1967.E. M. PR and other "styrene", M, Tsniiteneftehim, 1996, S. 38.The objective of the invention is to increase the efficiency of the process, which consists in increasing the conversion of ethylbenzene at the stage of dehydrogenation.This object is achieved by the described method of producing styrene by catalytic dehydrogenation of ethylbenzene in the presence of water vapor with posledney faction, etilbenzene fraction of recycling that is returned to the mixing with the original fresh ethylbenzene at the entrance of the reactor block, and styrene - rectified, by maintaining the concentration of styrene in etilbenzene charge at no more than about 0.15 wt.%.Studies have shown that the decrease in the content of styrene in etilbenzene charge up to a level of 0.15 wt.% allows to significantly improve the conversion of ethylbenzene, because, apparently, the inhibitory effect of styrene in raw materials, as a result of adsorption on his catalytic centers because of differences in the absorption coefficients of styrene and ethylbenzene. The decrease in the concentration of styrene in etilbenzene charge below the specified limit does not lead to a significant change in the conversion of ethylbenzene, but causes considerable technical difficulties in implementing the invention.It is known that for splitting a pair of ethylbenzene - styrene close boiling points required columns with a large number of plates. So, in practice, in the industry at a residual styrene content in return ethylbenzene at 1.5 wt.% use columns with at least 70 plates. Therefore, the column selection return ethylbenzene often perform a "split" consisting ofits spontaneous polymerization", M, Tsniiteneftehim, 1974, S. 23.The implementation of the present invention, namely, maintaining the concentration of styrene in etilbenzene the charge level of 0.15 wt.%, will require reducing the amount of styrene in return ethylbenzene to less than 0.5 wt.%. The decrease in the concentration of styrene in return ethylbenzene to such a level using conventional distillation columns would require significant capital and energy costs, which would reduce the effectiveness of this invention.The full effectiveness of the implementation of the present invention is achieved by using special regular nozzles installed in the separation columns instead of the usual distillation plates. Use regular packing, for example of the type intalox company Norton, allows after the replacement of the existing plates in the current column to dramatically improve the efficiency of the column, to reduce the hydraulic resistance at the same capacity, to reduce the temperature in the cube columns and loss of styrene in the polymer. Thanks for such a replacement of the styrene content in the return ethylbenzene can be reduced to the desired according to this invention without significant capital e invention is illustrated by the following examples:
Example 1 (comparative). Acibenzolar the mixture obtained after mixing of the fresh and return ethylbenzene, styrene content in a mixture of 0.5. %, was subjected to dehydrogenation on the oxide catalyst MST-75 in an isothermal reactor. The process was carried out at a temperature of 600oC, the mass ratio of raw materials : water vapor equal to 1 : 2, and a space velocity of etilbenzene charge 1 hour - 1. The conversion of ethylbenzene was 62.9 wt. % with a selectivity of conversion of ethylbenzene to styrene 96,7%.Example 2. Acibenzolar the mixture obtained after mixing of the fresh and return ethylbenzene, styrene content in a mixture of 0.15 wt.% were subjected to dehydrogenation on the oxide catalyst MST-75 in an isothermal reactor. The process was carried out at a temperature of 600oC, the mass ratio of raw materials : water vapor equal to 1 : 2 and a space velocity of etilbenzene charge 1 hour - 1. The conversion of ethylbenzene amounted to 67.9 wt.% when the selectivity of the conversion of ethylbenzene to styrene 96,7%.Thus, as can be seen from the presented data, the decrease in the concentration of styrene in etilbenzene charge up to a level of 0.15 wt.% increases the conversion of ethylbenzene to styrene. The way in which the group benzatropine faction, return etilbenzene faction and styrene-rectified, characterized in that the concentration of styrene in etilbenzene the charge coming into the dehydrogenation reactor, is maintained at a level no higher than about 0.15 wt.%
FIELD: petrochemical processes.
SUBSTANCE: method provides for three-stage isolation of aromatic hydrocarbons in the separation, absorption, and separation stages using, as absorbent, ethylbenzene rectification bottom residue. Loaded absorbent containing diethylbenzene isomer mixture serves as starting material for production of alkylaromatic hydrocarbons including divinylbenzene.
EFFECT: reduced loss of aromatic hydrocarbons and improved economical efficiency of styrene production process.
2 dwg, 1 tbl, 5 ex
FIELD: chemistry of aromatic compounds, petroleum chemistry, chemical technology.
SUBSTANCE: method involves carrying out three-stage isolation of aromatic hydrocarbons by separation, absorption and separation using at absorption stage atmosphere distillate off (TS 38.401194-92) as absorbent and prepared in manufacturing oil-polymeric resin by catalytic method. Invention provides reducing loss of aromatic hydrocarbons and improving economic indices of process in manufacturing styrene.
EFFECT: improved method for isolation.
1 tbl, 2 dwg, 5 ex
FIELD: chemistry of aromatic compounds, chemical technology.
SUBSTANCE: process involves the following stages: feeding (C2-C5)-alkane, for example, ethane and (C2-C5)-alkyl-substituted aromatic compound, for example, ethylbenzene into dehydrogenation reactor for the simultaneous dehydrogenation to (C2-C5)-alkene, for example, to ethylene, and (C2-C5)-alkenyl-substituted aromatic compound, for example, styrene; separation of the outlet dehydrogenation flow for extraction of gaseous flow containing alkene, hydrogen and alkane, and for extraction of aromatic compounds with the high effectiveness by cooling and compression; feeding a gaseous flow and (C6-C12)-aromatic compound into the alkylation reactor for preparing the corresponding (C2-C5)-alkyl-substituted aromatic compound that is recirculated into the dehydrogenation reactor; feeding the blowing flow from the alkylation unit containing alkane and hydrogen for the separation stage by using cryogenic separator for extraction of alkane that is recirculated into the dehydrogenation reactor, and hydrogen that is extracted with the purity value 99%. Invention provides the development of economic and highly effective process for preparing alkenyl-substituted aromatic compounds.
EFFECT: improved preparing method.
61 cl, 2 tbl, 2 dwg, 2 ex
FIELD: chemical industry; catalyzers for dehydrogenation of the alkyl-aromatic hydrocarbons.
SUBSTANCE: the invention presents the catalyzer used for dehydrogenation the alkyl-aromatic hydrocarbons of the following composition (in mass%): potassium compounds (in terms of potassium oxide) - 8.0-25.0; magnesium compounds and-or calcium compounds (in terms of magnesium oxide and-or calcium oxide) - 0.2-7.0; molybdenum oxide - 0.7-7.0; cerium oxide - 1.0-15.0; Portland cement - 0.5-12.0; lanthanum oxide and-or neodymium oxide - 0.01-7.0; iron oxide - the rest. The technical result of the invention is the increase of activity, selectivity of the catalyzer, as well as the thermal stability, which increases the catalyzer service life.
EFFECT: the invention ensures the increase of activity, selectivity, thermal stability and the service life of the catalyzer.
4 cl, 20 ex, 2 tbl, 2 dwg
FIELD: petrochemical industry; methods of production of styrene.
SUBSTANCE: the invention is pertaining to the field of petrochemical industry, in particular, to the method of production of styrene. The invention provides for dehydrogenation of the ethylbenzene charge gained after mixing of the fresh ethylbenzene with the recycled ethylbenzene on the ferrioxide catalytic agent at presence of the steam at the mass ratio of the raw to the steam of no less than 1:2, at the temperature of 580-640°С and the volumetric speed of feeding of the ethylbenzene charge of 0.23-0.45 m3/h. The hydrocarbon condensate (the product of the dehydrogenation) containing styrene, the unreacted ethylbenzene, the by-products including the phenyl acetylene impurity before the stage of the rectification is hydrogenated using the palladium-containing catalytic agents at the temperature of 20-30°С, the volumetric speed of 4.5-5.0 m3/h-1 and at the volumetric ratio of the hydrogen : raw - 35-45. The technical result of the invention is the increased purity of the produced styrene without reduction of productivity of the whole process of the marketable styrene.
EFFECT: the invention ensures the increased purity of the produced styrene without reduction of productivity of the whole process of the marketable styrene.
1 tbl, 8 ex
FIELD: industrial organic synthesis.
SUBSTANCE: ethylbenzene blend obtained through blending fresh ethylbenzene and recycled ethylbenzene with styrene content not above 0.1 wt % is subjected to catalytic dehydrogenation in presence of water steam at feed-to-steam weight ratio 1:2, temperature 600°C, ethylbenzene blend supply space velocity 0.5-1.0 h-1, and reactor pressure maintained within a range of 45 to 80 kPa absolute. Multistep rectification gives rectified styrene with concentration of desired product at least 99.8% and phenylacetylene impurity level not higher than 0.01 wt %. Recycled ethylbenzene is blended with fresh ethylbenzene and resulting ethylbenzene blend containing no more than 0.1 wt % styrene is supplied to dehydrogenation unit.
EFFECT: increased ethylbenzene-to-styrene conversion, improved process selectivity, and reduced level of phenylacetylene in commercial product.
FIELD: industrial organic synthesis.
SUBSTANCE: embodiments of invention are accomplished via liquid-phase dehydration of methyl phenyl carbinol-containing feedstock in presence of acid-type catalyst in column-type reactor-rectifier comprising still portion, built-in heat-exchanger, and rectification portion, volume of still portion constituting 80% of built-in heat-exchanger volume. Temperature of till portion of reactor-rectifier is 140-205°C and temperature in rectification portion 130-180°C. Advantageously, methyl phenyl carbinol-containing feedstock is supplied to and/or under built-in heat-exchanger and catalyst or mixture of catalyst with feedstock and/or still product is supplied to still portion at mixing. Linear velocity of reaction mass vapors within free cross-section of reactor is 0.05 to 0.9 m/s, residence time of styrene in reaction zone 0.05 to 50 sec, and residence time of still product in reactor 5 to 500 h.
EFFECT: increased conversion of feedstock and final product formation selectivity.
5 cl, 14 ex
FIELD: industrial organic synthesis.
SUBSTANCE: invention relates to production of alkylaryl hydroperoxides useful as starting material in production of propylene oxide and alkenylaryl. Process of invention comprises following stages: oxidation of alkylaryl compound to form reaction product containing alkylaryl hydroperoxide; contacting at least part of reaction product with basic aqueous solution; separation of hydrocarbon phase containing alkylaryl hydroperoxide from aqueous phase; containing at least part of above hydrocarbon phase with aqueous solution containing waste water, said aqueous solution containing less than 0.2% alkali metal and/or salt (determined as ratio of metal component to total amount of solution); and separation of hydrocarbon phase from aqueous phase. By bringing at least part of above hydrocarbon phase containing alkylaryl hydroperoxide into interaction with propylene and catalyst, alkylaryl hydroxide and propylene oxide are obtained. At least part of propylene oxide is then separated from alkylaryl hydroxide. Dehydration of at least part of alkylaryl hydroxide results in formation of alkenylaryl.
EFFECT: reduced amount of contaminating by-products in alkylaryl hydroperoxide preparation stage.
8 cl, 4 ex
FIELD: hydrogenation-dehydrogenation catalysts.
SUBSTANCE: invention provides catalyst based on iron oxide and lanthanide compound wherein at least part of iron oxide is prepared via a method including thermal decomposition of iron halide and which contains lanthanide in amount corresponding to 0.07 to 0.15 mole per mole iron oxide found in catalyst (calculated as Fe2O3). A catalyst is also described wherein part of iron oxide contains residual halide. Preparation of catalyst involves providing a mixture containing sufficient amounts of at least iron oxide and lanthanide compound followed by calcination of the mixture. Alkylaromatic compound dehydrogenation process is further described involving contact of raw feed containing alkylaromatic compound with above-described catalyst as well as polymer or copolymer production process involving production of alkenylaromatic compound as described above and subsequent polymerization thereof or copolymerization with a monomer.
EFFECT: enabled production of alkenylaromatic compounds with improved characteristics owing de decreased formation of by-products.
18 cl, 2 ex
FIELD: industrial organic synthesis.
SUBSTANCE: linear alpha-methylstyrene dimers that can be used as molecular weight regulators for various polymers, as varnish solvents, and as base material in production of synthetic oils are obtained via oligomerization of α-methylstyrene in presence of zeolite ZSM-12 in H form in amount 1 to 10% at temperature 60-120°C.
EFFECT: increased selectivity and simplified production process.
1 tbl, 8 ex