The method of producing styrene

 

(57) Abstract:

The invention relates to a method for producing styrene by digitala methylphenylcarbinol fraction containing up to 3 wt.% heavy residues produced in the production process of propylene oxide and styrene, in the presence of water vapor on the catalyst containing alumina, and the process is carried out by adding to the original methylphenylcarbinol fraction of water vapor and hydrogen-containing gas mass ratio of methylphenylcarbinol : water vapor : hydrogen, equal 1: 0,03 - 0,6 : 0,0004 - 0,001, and heating in a single stream to the reaction temperature before entering the catalytic zone. This method allows to reduce the consumption of water vapor more than 2 times. 1 Il., 6 table.

The invention relates to the petrochemical industry and can be used in the process for the joint production of propylene oxide and styrene.

A known method of producing styrene by dehydration of phenethyl alcohol in the vapor phase at a temperature of 200oC on zeolite-containing catalyst and the weight dilution phenethyl alcohol : nitrogen = 1:2,2 (Japan's Bid 61-72727, MKI C 07 C 15/46, C 07 C 1/24, publ. 14.04.86).

The disadvantage of this method is n what idracula of methylphenylcarbinol in the vapor phase at a temperature of 270 - 350oC in the presence of the oxide catalyst dehydration, with the introduction into the reaction zone from 0.1 to 4 moles of steam per 1 mol of the raw material dehydration. Moreover, the raw material may contain not more than 60 wt.% of acetophenone. (U.S. patent 3658928, NCI 585-437, MKI C 07 C 15/10, publ. 25.04.1972). The disadvantage of this method are restrictions on raw and not a high yield of styrene.

The closest in technical essence is a method of producing styrene by dehydration of methylphenylcarbinol on the catalyst is aluminum oxide (AV. St. USSR 1309518, MKI C 07 C 15/46 1995) in a two-stage adiabatic reactors with intermediate heating of the contact strip and the intermediate separation of resin from the faction of methylphenylcarbinol supplied to the dehydration, in order to increase the yield of styrene selected resin in an amount of 0.6 to 3 wt. % injected into a fraction methylphenylcarbinol supplied to the dehydration. The disadvantage of this method is the low duration of operation of the catalyst by reducing his activity as a result of tasmainia and deposits it sodium salt.

The essence of the claimed invention to provide a styrene by dehydration methylphenylcarbinol fraction containing up to 3 wt.% heavy on the catalyst, ainol : water vapor : hydrogen, equal to 1:0,03-0,6:0,0004-0,001 by weight, and heated in a single stream to the reaction temperature before entering the catalytic zone.

The scheme described method of producing styrene shown in Fig. 1.

Fraction of methylphenylcarbinol, (stream 1) is mixed with water vapor (stream 2) and hydrogen gas (stream 3), then the total flow is heated in the heating zone 4 to the reaction temperature and (stream 5) is served in the reactor 6. In the reactor 6, a catalyst containing oxide of aluminum, while reactions proceed dehydration, hydrodealkylation, hydrogenation. Produce from the reactor 6 through line 7 is fed to the condenser 8, from which liquid products containing styrene, enter on line 9 the separation by distillation, and neskondensirovannyh gas containing unreacted hydrogen and methane in the recycle line 10 in the heating zone 4. Excess neskondensirovannyh gas from line 10 to line 11 is given to the fuel system or is used in the heating zone 4. As the hydrogen-containing gas is used metanotion fraction containing 90% on. of hydrogen.

Distinctive features of the invention is the addition of raw materials, containing up to 3% of the mass. heavy, water vapor and hydrogen-containing gas bratory reaction before entering the catalytic zone. When comparing essential features of the invention with those of the prototype it is possible to draw a conclusion on the conformity of the proposed technical solution the criterion of "novelty". Add in methylphenylcarbinol heavy (formed during oxidation of benzene to cumene hydroperoxide; epoxidation of propylene by hydropredict ethylbenzene; dehydration methylphenylcarbinol in styrene; and in the stages of separation of the products of the epoxidation and separation of the condensate after dehydration), which were previously in the waste, or the use of undertreated (received less clear rectification) methylphenylcarbinol fraction, heating it in a certain proportion in a mixture with water vapor and hydrogen to the reaction temperature before entering the catalytic zone provides additional amount of styrene due to decomposition and selective hydrogenation of these wastes. The greatest effect in the process is achieved when the claimed ratio methylphenylcarbinol : water vapor : hydrogen. The introduction of new distinctive characteristics in combination with the achieved effect is not described in any similar way, refers to the "inventive step" of the proposed method. The claimed invention meets the criterion of p is at spas obtain propylene oxide and styrene.

The inventive method is illustrated by the following examples:

Example 1 (comparative). Dehydration of methylphenylcarbinol (IFC) is conducted in a known manner on the catalyst is aluminum oxide. Volumetric feed rate on IFC 0,6 h-1. The temperature in the reactor 300oC. Dilution IFC : steam 1:1,475 by weight. In a reactor loaded with 1800 ml of catalyst. The flow fraction methylphenylcarbinol containing IFC, was aged 1.5 kg/h and water vapor 1,59 kg/h

The composition of the feedstock and catalyzate are given in table. 1.

Conversion methylphenylcarbinol:

K= (1270,95-98,54)100/1270,95=92,25%

The output of styrene missed IFC:

K1= (958,36-0,30) 122,17 100/1270,95 104,15 = 88,42% say.

The output of styrene decomposed IFC:

K2=(958,36-0,30)122,17100/(1270,95 98,54)104,15 = 95,85% say.

The flow rate of water vapor was:

Pp=1590/(958,36-0,30)=1,67 g/g of styrene

Example 2. Dehydration of methylphenylcarbinol conduct of the proposed method on the catalyst is aluminum oxide. Fraction methylphenylcarbinol mixed with water vapor and metabodrene faction in the ratio methylphenylcarbinol : water vapor : hydrogen of 1:0,60:0.004 percent by weight, is heated in the same thread in the heating zone 4 to a temperature of 300

The composition of the feedstock and catalyzate are shown in table 2.

conversion methylphenylcarbinol:

K= (1270,95-77,47)100/1270,95=93,90%

The output of styrene missed IFC:

K1= (987,17-0,30) 122,17 100/1270,95 104,15=91,08% say.

The output of styrene decomposed IFC:

K2= (987,17-0,30) 122,17 100/(1270,95-77,47) 104,15=96,99% say.

The flow rate of water vapor was:

Pp=900/(987,17-0,30)=0,91 g/g of styrene

Example 3. Dehydration of methylphenylcarbinol conduct of the proposed method on the catalyst zeolite NaX. Fraction methylphenylcarbinol mixed with water vapor and metabodrene faction in the ratio methylphenylcarbinol : water vapor : hydrogen of 1:0.03 to:0.004 percent by weight, is heated in the same thread in the heating zone 4 to a temperature of 250oC and served in the catalytic zone of the reactor 6. In a reactor loaded 1120 ml of catalyst. The volumetric rate at IFC 0,6 h-1. The flow fraction methylphenylcarbinol 2.6 kg/h of water vapor 0,078 kg/h and metabodrene faction, the hydrogen content in which was 90% about. - 129,42 l/h

The composition of raw materials and catalysis the Rola missed on IFC:

K1= (1664,74-0,52) 122,17 100/2202,72 104,15 = 88,62% say.

The output of styrene decomposed IFC:

K2=(1664,74-0,52)122,17100/(2202,72-217,61) 104,15=98,34% say.

The flow rate of water vapor was:

Pp=78/(1664,74-0,52)=0,047 g/g of styrene

Example 4. Dehydration of methylphenylcarbinol conduct of the proposed method on the catalyst is aluminum oxide. Fraction methylphenylcarbinol mixed with water vapor and metabodrene faction in the ratio methylphenylcarbinol : water vapor : hydrogen of 1:0,60:0,0004 by weight, is heated in the same thread in the heating zone 4 to a temperature of 350oC and served in the catalytic zone of the reactor 6. In a reactor loaded with 1300 ml of catalyst. The volumetric rate at IFC - 0,6 h-1. The flow fraction methylphenylcarbinol 3.0 kg/h, water vapor 1.8 kg/h and metabodrene faction, the hydrogen content in which was 90% about. - 14,93 l/h

The composition of the feedstock and catalyzate are given in table. 4.

Conversion methylphenylcarbinol:

K=(2665,68-17,22)100/2665,68=99,35%

The output of styrene missed IFC:

K1= (2248,84 - 0,6) 122,17 100/2665,68 104,15 = 98,93% say.

The output of styrene decomposed IFC:

K2= (2248,84 - 0,6) 122,17 100/(2665,68 - 17,22) 104,15=99,57% say.

Rashtra conduct of the proposed method on the catalyst is aluminum oxide. Fraction methylphenylcarbinol mixed with water vapor and metabodrene faction in the ratio methylphenylcarbinol : water vapor : hydrogen of 1:0.03 to:0,001 by weight, is heated in the same thread in the heating zone 4 to a temperature of 300oC and served in the catalytic zone of the reactor 6. In a reactor loaded with 1300 ml of catalyst. The volumetric rate at IFC 0,6 h-1. The flow fraction methylphenylcarbinol 3.0 kg/h, water vapor 0.09 kg/h and metabodrene faction, the hydrogen content in which was 90% about. - 37,33 l/h

The composition of the feedstock and catalyzate are given in table 5.

Conversion methylphenylcarbinol:

K=(2665,68-5,87)100/2665,68=99,78%

The output of styrene missed IFC:

K1= (2318,36 - 0,6) 122,17 100/2665,68 104,15 = 101,99% say.

The output of styrene decomposed IFC:

K2=(2318,36-0,6)122,17100/(2665,68-5,87) 104,15=102,21% say.

The flow rate of water vapor was:

Pp=90/(2318,36-0,6)=0,039 g/g of styrene

As is the additional education of styrene due to decay of heavy elements, so the value of K1and K2more than 100%.

Example 6. Dehydration IFC conducted according to the proposed method on the catalyst is aluminum oxide. Fraction IFC is mixed with water vapor is temperature 300oC and served in the catalytic zone of the reactor 6. In a reactor loaded with 1200 ml of catalyst. The volumetric rate at IFC 0.6 hour.-1. Consumption faction IFC kept 2.6 kg/h of water vapor 0,39 kg/h and metabodrene fractions containing 90% on. hydrogen - 12,94 l/h.

The composition of the feedstock and catalyzate are given in table. 6.

Conversion methylphenylcarbinol:

K=(2202,72-174,6)100/2202,72=92,07%

The output of styrene missed IFC:

K1= (1929,59 - 0,52) 122,17 100/2202,72 104,15 = 102,73% say.

The output of styrene decomposed IFC:

K2=(1929,59-0,52)122,17100/(2202,72-174,6) 104,15=111,57% say.

The flow rate of water vapor was:

Pp=390/(1929,59-0,52)=0,202 g/g of styrene

The quality of the styrene-rectified received on the proposed method of producing styrene by dehydration of methylphenylcarbinol corresponds to GOST 10003-90 standard for grade SDMF top grade.

The use of the proposed method of producing styrene by dehydration of methylphenylcarbinol allows to reduce the consumption of water vapor more than 2 times, to increase the production of styrene by 3% and reduce the expenditure ratio for methylphenylcarbinol 3%. Due to the parallel reactions of dehydration, hydrodealkylation, hyderabadbased to achieve the combination of all features.

The method of producing styrene by dehydration methylphenylcarbinol fraction containing up to 3 wt.% heavy, in the presence of water vapor on the catalyst containing alumina, characterized in that use raw materials, which add water vapor and hydrogen gas in a ratio methylphenylcarbinol : water vapor : hydrogen of 1 : 0.3 tooC 0,6 : 0,0004oC 0,001 by weight, and heated in a single stream to the reaction temperature before entering the catalytic zone.

 

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