SU1066978A1 - Process for preparing naphthalene and methylnaphthalenes - Google Patents

Abstract

THE METHOD OF PREPARING NAPHTHALINE AND METHYLNAPHTHALINOB by converting methane in the presence of (satsshizatoto high silica zeolite and nitrous oxide activator at elevated temperature, so that with the aim of increasing the yield of target products, zeolite is used as a catalyst the molar ratio of silica to alumina is 25-29. The process is carried out at 420-480 ° C and the reaction mixture is recirculated with a ratio of 20-50- (P s

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This invention relates to a method for producing aromatics as components of liquid hydrocarbon fuels, as well as raw materials for organic synthesis from natural gas and coal. It is economically feasible to develop a method for obtaining components of liquid hydrocarbon fuels and raw materials for organic synthesis from non-petroleum products, including natural gas and coal. A known method of processing natural gas (methane) into liquid hydrocarbons of fuel value according to the scheme methane 52ygеК "2-Ñ--с вод." With water napoMf 800-С OSSS HHSislCo + H, Hizal | tory or methanolGs. 2 Fischer-Tropsch paraffin or high-octane carbohydrate genus methanol (d This known method is a four-step process. In the first step after WA, the liquid gas from methane is converted by steam at 760-982 ° C and a mixture of 1: 5 or 1: 1. The yield of the mixture is 60% for the missed methane. In the second stage, the mixture of H2 + CO at 177343 C in the presence of a catalyst ZnO-CuO is converted to methanol. In accordance with known data, the output of methanol is no more than 30% on missed CO. At the third stage methanol and zeolite ZSM-5 at 250-650 ° C and a flow rate of methanol supply of 0.5-50 is converted to hydrocarbons with a yield of 46.6% by weight of hydrocarbons, of which 35-40% are aromatic hydrocarbons, the rest are gases. in the fourth stage, the gases are returned to reforming or alkylation. As a result of the four-stage process, liquid aromatic hydrocarbons are obtained with a boiling point of -40-170 ° C with a total yield of 9-10% of the initial amount of missed methane (without recirculation) C The process involves such an expensive and energy-intensive stage, as methane conversion in this steam. Taking into account the need for methane consumption for maintaining high tetro-pressure and pressure in individual stages, the coefficient of useful use of the raw material should be even lower. There is a known method of converting methane to methanol in one technological stage u2, and the process is carried out at a pressure of 50–200 atm, temperature, 320–4 ° C using natural gas to which 1.2–4 vol% is added. % of oxygen. As a catalyst, compositions containing Zn, Ni, Cd in the ratio of 2: 7: 1 or 2: 4: 4, or 2: 3: 5, or 2: 1: 1 are used. The degree of conversion of methane to methanol is 1.6-2%, and other organic oxygen-containing products - 0.1-0.17%. To obtain a liquid aromatic, hydrocarbon, neo-hydrocarbon. Second stage: the conversion of methanol on zeolites. The yield of the desired product at this stage is about 50%. In general, the yield of aromatic compounds to the initial amount of methane missed is about 0.8-1%. The main points of the liquid products are fractions consisting of aliphatic hydrocarbons and monoaromatic compounds with a boiling point not higher than 170 ° C. The effect that is closest to the predicted effect is a method for producing naphthalene and methyl naphthalenes by converting methane in the presence of a catalyst — a high-silica zeolite with a composition of 0.04% Na, 2.5–5% Al 2 O 3, 92–98% SiO. with a molar ratio of SiOj / Al-O, 30-68 in the presence of an activator — nitrous oxide. nitrogen at 350-50 ° C. The method provides for the conversion of methane in a single pass of 25-40%, while the reaction products contain 40-30% of aromatic hydrocarbons, which corresponds to a yield of the target product of 6-12% per leaked methane 3J. The disadvantage of this method is the low yield of the target products. The purpose of the invention is to increase the yield of target products. The goal is achieved. according to the method of producing naphthalene and methylnaphthalenes by converting methane in the presence of a catalyst — a high-silica zeolite and an activator — nitrous oxide at an elevated temperature in the amount of catalyst — use a zeolite with a mol ndad ratio of silica to alumina equal to 25-29; at 420-480 ° C and circulating the reaction mixture with a multiplicity of 20-50. The proposed method compared with limestone provides the conversion of methane by 30-60% with selectivity for aromatic hydrocarbons 60-90%, which corresponds to the yield of the target product 15-41%. missed methane, i.e. the yield of the target products increases significantly. The proposed method is carried out in one technological stage using high silica zeolite

with a molar ration of silica and alumina of 25-29, under the above conditions.

Example 1. A mixture of 30% sol SiOg, aluminum sulfate, tetrabutylammonium bromide and NaOH is loaded into an autoclave in a ratio in terms of oxides 30-50 SiO f XIOR. Crystallization is carried out at 175 ° C 3 dry tons. The precipitate is filtered off and washed with distilled water. The resulting high-silica zeolite (VCC) with a ratio of

SiO2 is treated with an air flow for 2 hours at, cooled to and ion exchange with 0.1 N is carried out. a solution of NH Cl + NH ob is then filtered, washed from C1 ions, dried for 10 hours, tableted, and a fraction of 0.5-0.25 mm is collected. A portion of the catalyst is loaded into the reactor of a flow-circulation catalytic installation, activated with an oxygen stream for 2 hours at 520 ° C, cooled to the reaction temperature. .

The reaction mixture of composition 33.3% by volume and 66.6% of CH is passed with a bulk velocity of 280-290 hours over the catalyst at. The recirculation is performed by a flow-circulating pump. Recycling ratio 50.

PRI mme R 2. The catalyst was prepared according to the method of example 1. The reaction mixture of the same composition as in example 1, is passed over the catalyst at 460 ° C with bulk velocity

280-290 h. The recycle ratio is 50,

Example 3. The catalyst is prepared according to the method of Example 1.

The reaction mixture of the same composition as in example 1 is passed over the catalyst at 460 ° C with a bulk velocity of 460-480 hours. The multiplicity of circulation 50..

Example 4. The catalyst was prepared according to the method of Example-Irf. The reaction mixture containing 50% KgO and 50% SND is passed with a bulk velocity of 280-290 hours over the catalyst at.

Gas mixture recycle ratio 50.

PRI me R 5. The catalyst was prepared according to the method of Example 1. The reaction mixture of the composition CH.:N, .0 was passed with a bulk velocity of 280 hours at 480 ° C over the catalyst. Gas mixture recycle ratio 50.

PRI me R 6. The catalyst was prepared according to the method of example 1. The reaction mixture of 1: 1 composition was passed with a bulk velocity of 280 hours at above the catalyst. Gas mixture recycle ratio 20.

Example 7. A catalyst was prepared as described in Example 1. The reaction mixture of composition CH4: N2O 1: 1. was passed with a bulk velocity of 280 with the catalyst above without recirculation of the gas mixture.

The composition of the products is given in the table.

28.4 27.7 28.5

53.8 81.0 43.4

Missed carbohydrate yield

15.3 22.4 12.4 ethane,%

leaving the hydrocarbon fraction of the reaction products, May. %

0.9

0.21

benzene

6.3 2.26 toluene

21.7 9.83 xylenes

4.2 8.44 trimethylbenzene

8.4 4.55 naphthalene

38.6 28.7 Methylnaphthalenes

29.9 46.0 dimethylnaphthalenes

51.9 55.4 56.1 50.2 49.3 74.3 64.8 45.5

25.6 41.1 36.4 22.0

0; 49

3.73

13.8

7.9

3.4

26.2

44.4

The table shows that, in contrast to the prototype, in examples 4 and 5 of the invention a higher yield of hydrocarbons is achieved (15-41% instead of 9-10%

Table continuation

prototype), with 78-80% of the hydrocarbon reaction products being naphthalene and its derivatives.

Claims (1)

METHOD FOR PRODUCING NAPHTHALINE AND METHYLNAPHTHALINES by converting methane in the presence of a (catalyzed high siliceous zeolite and nitrous oxide activator at an elevated temperature, with the aim that, in order to increase the yield of target products, use as a catalyst zeolite with a molar ratio of silicon dioxide to alumina equal to 25-29, the process is carried out at 420-480 ° C and the reaction mixture is recycled with a ratio of 20-50 ·.