RU2594564C1 - Catalyst and method of converting ethanol, methanol or mixture thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of aromatic hydrocarbons from alcohols in particular, to a catalyst for conversion of ethanol, methanol or mixture thereof into aromatic hydrocarbons. Catalyst contains zeolite HZSM-5, ZnO and additionally contains Fe₂O₃ and MgO, with following composition in terms of oxides, wt%: Al₂O₃ - 1.0-1.3; Fe₂O₃ - 0.05-0.10; MgO - 0.05-0.10; ZnO - 0.05-0.10; SiO₂ - balance. Also disclosed is a method of converting ethanol, methanol or mixture thereof into aromatic hydrocarbons.

EFFECT: invention enables to increase content of naphthalenes in product with high selectivity on aromatic compounds.

3 cl, 1 dwg, 4 ex

Description

The invention relates to the field of production of aromatic hydrocarbons from alcohols, namely from ethanol, methanol or a mixture thereof at atmospheric pressure. The resulting aromatic hydrocarbons can be used as raw materials for organic synthesis and components of liquid fuels.

As analogues, the following inventions are considered.

A known method of producing high molecular weight aromatic hydrocarbons by catalytic conversion of 96% ethanol or a mixture of ethanol-isobutanol (3: 1) at 400 ° C, a volumetric rate of liquid feed 2 h ^-1 , a pressure of 0.1-5.0 MPa on zeolite-containing the catalyst. The method is characterized in that a zeolite-containing catalyst of the composition is used: HZSM-5 - 98 wt.%, Ce ₂ O ₃ - 2 wt.% [Frantsuzova Η.Α., Tretyakov K.V., Talyshinsky R.M. Tretyakov V.F. A method of producing high molecular weight aromatic hydrocarbons, RF patent 2454388, cl. IPC С07С 1/20, June 27, 2012].

The disadvantage of this process is the low yield of aromatic hydrocarbons, equal to 28%.

A known method of producing high molecular weight aromatic hydrocarbons by catalytic conversion of 96% ethanol at 350-400 ° C, the volumetric rate of liquid feed 1 h ^-1 on a zeolite-containing catalyst HZSM-5 [Glazneva TS, Shmachkova VP, Paukshtis E.A. Acidic properties of fiberglass materials // React. Kinet. Catal. Lett. - 2007. - Vol. 92. - R. 303-309].

The disadvantages of this method are the low selectivity and productivity of the catalyst with a short duration of the reaction cycle, not exceeding 2 hours

The disadvantages of the proposed methods are the low yield of aromatic hydrocarbons to the skipped alcohol and a significant amount of olefinic hydrocarbons at the outlet of the reaction system, which are potential raw materials for the production of aromatic compounds.

Closest to the proposed combination of features and technical result (prototype) are the catalyst and method described in ed. USSR No. 589903 A, publ. 01/30/1978. In a known solution for the preparation of aromatic compounds from oxygen-containing compounds, including methanol, ethanol, or a mixture thereof, a zeolite catalyst containing aluminum and silicon oxides in a molar ratio of 12-3000, including HZSM-5 zeolite containing not more than 10 wt. .% metals selected from zinc, copper, cadmium, nickel, alkaline earth metals and platinum group metals. At a space velocity of 0.64-0.71 h ^-1 , a temperature of 333-434 ° C and atmospheric pressure, 100% methanol conversion is achieved with an aromatic hydrocarbon selectivity of 40-46%.

The composition of the resulting aromatic compounds contains a small proportion of naphthalenes, a valuable component of motor fuels. In addition, the performance of the method is low.

The objective of the invention is to increase the content of naphthalenes in the product with high selectivity for aromatic compounds.

To solve this problem, a catalyst is proposed for the conversion of a mixture of ethanol and methanol into aromatic hydrocarbons containing zeolite HZSM-5, ZnO and additionally Fe ₂ O ₃ and MgO with the following composition based on oxides, wt.%:

Al ₂ O ₃ - 1.0-1.3

Fe ₂ O ₃ - 0.05-0.10

MgO - 0.05-0.10

ZnO - 0.05-0.10

SiO ₂ - the rest.

To solve this problem there is also provided a method of converting a mixture of ethanol and methanol to aromatic hydrocarbons in the presence of catalyst at atmospheric pressure and a space velocity of liquid feed of 1.0-1.5 hr ^-1 in a two-section reactor consisting of two reactors connected in series, with 420-440 ° C in the first reactor and 430-450 ° C in the second reactor containing twice as much catalyst as the first, and the products leaving the first reactor are separated into a liquid phase containing aromatic compounds, and ha Comprising ethylene and / or propylene, the liquid phase withdrawn from the reactor as the product gas and introduced into the second reactor for further conversion to aromatics.

After conversion in the second reactor, unreacted olefins - ethylene and / or propylene can be returned to the inlet of the second reactor to achieve a more complete conversion.

In FIG. 1 shows a diagram of a two-section reactor.

The conversion of alcohols - ethanol and methanol - is carried out in reactors 1 (first reactor) and 2 (second reactor). Methanol mixed with ethanol enters reactor 1, where they are converted on an Fe-HZSM-5 catalyst (3) to aromatics and ethylene and / or propylene, which are separated after the refrigerator 4. Gaseous ethylene and / or propylene enters the next flow reactor 2 (also containing a catalyst layer 3), in which its additional oligomerization to aromatic hydrocarbons occurs. After that, unreacted ethylene and / or propylene can be separated and returned to the inlet of the second reactor. The composition of aromatic hydrocarbons, judging by chromatographic analysis, is identical after the first and second technological section of the conversion of alcohols, which indicates the successive conversion of alcohols through ethylene and / or propylene to aromatic hydrocarbons. In the separator 5, after the reactor 1, the aqueous layer and the organic layer (which are mainly ArH aromatic hydrocarbons) are separated.

In the conversion of pure methanol without ethanol, ethylene yield is not observed, only propylene is formed. Therefore, after the second reactor in the separator in the presence of methanol in the mixture in the liquid there is a layer of water. In the absence of methanol, no pure water is formed in reactor 2 in pure ethanol, and only an organic layer accumulates in the separator, in which aromatic compounds dominate up to 80%. The remaining hydrocarbons are a mixture of cyclic saturated compounds and their derivatives.

Examples.

Example 1. In the first and second section is loaded respectively 10 and 20 ml of the catalyst composition, wt.%:

Al ₂ O ₃ - 1.3

Fe ₂ O ₃ - 0.05

MgO - 0.05

ZnO - 0.05

SiO ₂ - the rest (98.55).

At a space velocity of 1 h ⁻¹ in the liquid feed consisting of methanol and ethanol in a molar ratio of CH ₃ OH: C ₂ H ₅ OH = 1: 1 and the temperature in the middle of the layer of the first section 420 ° C, in the second section 430 ° C at in the absence of olefin recirculation, an aromatic hydrocarbon yield of 28% is achieved with a 99% alcohol conversion. The composition of aromatic compounds in the organic phase according to chromatography: 25% xylene, 10% toluene, 0.5% benzene, 5% naphthalenes, the rest is ethylbenzene and other benzene derivatives.

Example 2. In the first and second section are loaded, respectively, 10 and 20 ml of the catalyst composition, wt.%:

Al ₂ O ₃ - 1.0

Fe ₂ O ₃ - 0.10

MgO - 0.08

ZnO - 0.06

SiO ₂ - the rest (98.76).

At a volumetric rate of 1.5 h ⁻¹ in liquid feed consisting of methanol and ethanol in a molar ratio of CH ₃ OH: C ₂ H ₅ OH = 0.5: 1 and the temperature in the middle of the layer of the first section 430 ° C, in the second section 450 ° C in the absence of recirculation of olefins, the yield of aromatic hydrocarbons of 28% is achieved at a conversion of alcohols of 99%. The composition of aromatic compounds in the organic phase according to chromatography: 30% xylenes, 15% toluene, 0.3% benzene, 7% naphthalenes, the rest is ethylbenzene and other benzene derivatives.

Example 3. In the first and second section are loaded, respectively, 10 and 20 ml of the catalyst composition, wt.%:

Al ₂ O ₃ - 1.0

Fe ₂ O ₃ - 0.10

MgO - 0.10

ZnO - 0.10

SiO ₂ - the rest (98.7).

At a volumetric rate of 1.5 h ⁻¹ in liquid feed consisting of methanol and ethanol in a molar ratio of CH ₃ OH: C ₂ H ₅ OH = 1.5: 1 and the temperature in the middle of the layer of the first section 430 ° C, in the second section 450 ° C with the recirculation of olefins, an aromatic hydrocarbon yield of 38% is achieved with an alcohol conversion of 98.5%. The composition of aromatic compounds in the organic phase according to chromatography: 30% xylenes, 18% toluene, 0.5% benzene, 10% naphthalenes, the rest is ethylbenzene and other benzene derivatives.

Example 4. In the first and second section are loaded, respectively, 10 and 20 ml of the catalyst composition, wt.%:

Al ₂ O ₃ - 1.2

Fe ₂ O ₃ - 0.10

MgO - 0.10

ZnO - 0.10

SiO ₂ - the rest (98.5).

At a WHSV of 1.0 hr ^-1 for the raw material liquid consisting of methanol and ethanol in a molar ratio CH ₃ OH: C ₂ H ₅ OH = 0.8: 1 and the temperature in the middle layer of the first section 440 ° C, in the second section 450 ° C with the recirculation of olefins, an aromatic hydrocarbon yield of 47% is achieved with an alcohol conversion of 99.5%. The composition of aromatic compounds in the organic phase according to chromatography: 34% xylene, 17% toluene, 0.7% benzene, 12% naphthalenes, the rest is ethylbenzene and other benzene derivatives.

Claims (3)

1. The catalyst for the conversion of ethanol, methanol or mixtures thereof to aromatic hydrocarbons containing zeolite HZSM-5 and ZnO, characterized in that it additionally contains Fe ₂ O ₃ and MgO in the following composition, based on oxides, wt.%:
Al ₂ O ₃ 1.0-1.3 Fe ₂ O ₃ 0.05-0.10 MgO 0.05-0.10 Zno 0.05-0.10 SiO ₂ rest 2. A method of converting ethanol, methanol, or a mixture thereof into aromatic hydrocarbons in the presence of a catalyst containing HZSM-5 zeolite and ZnO, at elevated temperature and atmospheric pressure, characterized in that the catalyst according to claim 1 is used, and the conversion is carried out at a space velocity of liquid feedstock of 1.0-1.5 hr ^-1 in a two-section reactor consisting of two serially connected reactors, at a temperature of 420-440 ° C in the first reactor and 430-450 ° C in the second reactor containing twice as much catalyst than the first , and products coming out of ne Vågå reactor is separated into a liquid phase comprising the aromatic compound and a gas containing ethylene and / or propylene, the liquid phase withdrawn from the reactor as the product gas and introduced into the second reactor for further conversion to aromatics. 3. The method according to p. 2, characterized in that after conversion in the second reactor, unreacted ethylene and / or propylene is returned to the inlet of the second reactor.

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