The method of producing styrene
(57) Abstract:The invention relates to the petrochemical industry and can be used to obtain styrene by dehydration of methylphenylcarbinol during the joint production of propylene oxide and styrene. The essence of the invention is the implementation of evaporation of liquid raw materials and overheating directly in the reaction zone due to the heat of the water vapour coming from superheater gas contact, and from the superheater furnace, and high-boiling products comprising methylphenylcarbinol, pre-evaporation are not separated and decomposed into a number of valuable products in the reactor together with the bulk of the raw materials. 4 tab., 1 Il. The invention relates to cyclic compounds, in particular, to dehydration methylphenylcarbinol in styrene in the joint process of obtaining propylene oxide and styrene.Known methods of dehydration alkylaromatic alcohols in the vapor phase in the adiabatic reactor using a catalyst of titanium oxide, thorium, aluminum at a temperature of 180-280oC [1, 2].The disadvantage of these methods is the low yield of the target products and vyskytla of methylphenylcarbinol in styrene with water vapor in the presence of a catalyst based on aluminum oxide in a two-stage adiabatic reactors with intermediate heating of the contact strip, providing equality of the temperatures at the inlet to each stage of contact . The disadvantage of this method is also insufficient conversion methylphenylcarbinol and selectivity, as well as increased heat loss of water vapor on the stages of overheating of the charge and hydrocarbons in the selection of the high-boiling products from the evaporator, the burning of which affects the sanitary and technical condition of production. To this we must add the need for periodic cleaning of the superheater charge from the polymer deposits, which leads to unplanned production stops.The proposed method devoid of the above disadvantages, because it allows completely excluded from the process schema nodes evaporation and overheating of the mixture to 320oC and, consequently, to reduce heat loss and hydrocarbons avoid stopping systems associated with the cleaning of the superheater charge.The aim of the invention is the reduction of energy consumption, raw material consumption and stabilization of production and the improvement of sanitary and technical condition of production.This goal is achieved by the described method, whereby the evaporation of liquid raw materials and overheating conduct C is Aza, and from the superheater furnace, and high-boiling products comprising methylphenylcarbinol, pre-evaporation are not separated and decomposed into a number of valuable products in the reactor together with the bulk of the raw materials.Studies have shown that decomposition of high boiling point selected from the evaporator at a temperature of 280-320oC, is formed mainly of styrene and ethylbenzene.In the drawing is given of the proposed scheme dehydration.In this way raw methylphenylcarbinol fraction is fed through line 1 into the convection part of the oven 2, where it is heated to a temperature of 180-190oC due to the heat from flue gases and line 3 in liquid form is directed to mix with water vapor and further along the line 4 with a temperature of 270-320oC in the reactor of the first stage 5.Contact the gas line 6 enters the interstage superheater 7, where it is superheated to a temperature of 270-320oC, then line 8 is directed into the reactor of the second stage 9. Contact the gas after the reactor through line 10 is directed to the cooling and rectification.Water vapor flows through line 11 into the furnace 2, where it is superheated to a temperature of 500-700oC and on line 12 enters partially on line 13 is on line 15.Regulating the amount of steam coming from the superheating-chamber of the furnace, is produced in the reactor 5 and the interstage superheater 7 a flap with incomplete cover 14 that can withstand the required temperature in each of the reactors.Every 400-1000 hours of work is the regeneration of the catalyst vapor mixture.The invention is illustrated by the following inventions.Example 1. Fraction of methylphenylcarbinol is fed into the evaporator, where mixed with water vapor in the vapor phase enters the heat exchanger for indirect overheated water vapor coming from the interstage superheater, to a temperature of 270-320oC and is directed in the first stage of contact. Contact the gas at the outlet of the first stage is heated to the reaction temperature in the interstage superheater and enters the second stage contacting. Taglocity residue selected from the evaporator is sent to incineration.Dehydration is carried out at two values of the volumetric velocity on the catalyst alumina (10 l) under the following conditions (see tab. 1).Thus the following results are obtained (see tab. 2).Example 2 (offers the superheating furnace to a temperature of 180-190oC in liquid form without separation from it storable. The evaporator and the superheater charge of technological schemes are excluded.If this is observed the following mode of dehydration (see table. 3).Thus the following results are obtained (see tab. 4).Thus, the introduction of this scheme in the current production of propylene oxide together with styrene at JSC "Nizhnekamskneftekhim" will allow you to:
to exclude from the process schema nodes evaporation and overheating of raw materials and thus reduce heat loss by evaporation and overheating in devices and pipelines due to the feed in the reaction zone liquid raw material;
to increase the productivity of the reactors styrene by increasing conversion and decomposition of IFC and taglocity previously withdrawn from the evaporators;
accordingly reduce consumption of raw materials and water vapor;
to improve the sanitary condition of production by eliminating the operation of the combustion taglocity drawn from the evaporator. The method of producing styrene by dehydration of methylphenylcarbinol in a two-stage reactor on the catalyst is aluminum oxide in the presence of water vapor heated flow coming from the first the action methylphenylcarbinol in liquid form, pre-heated in the convection part of the superheating furnace up to 180 - 190oAnd mixed before entry into the catalyst bed of the first stage reactor at a mass ratio of 1 : 1,0 - 1,2 with water vapor coming from the interstage superheater and directly from the superheater furnace.
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