CN115974637A - The method of ethylbenzene and ethanol or ethylene alkylation synthesis mixed diethylbenzene - Google Patents

Abstract

The invention relates to a method for alkylating ethylbenzene and ethanol or ethylene to synthesize mixed diethylbenzene in the technical field of chemical synthesis. In the reaction device, the catalyst Mn@ZSM‑5 is loaded in a fixed reaction bed, and the reaction raw material is ethyl Benzene and ethanol or ethylene, the reaction temperature is 280~320°C, the reaction pressure is 0.5Mpa~1.5MPa, the molar ratio of ethylbenzene to ethanol or ethylene is 10~14:1, and the weight space velocity is 0.5h‑1. In the present invention, the Mn@ZSM-5 catalyst adjusts the surface acidity distribution and pores of the ZSM-5 molecular sieve through the Mn element to obtain a mixed diethylbenzene catalyst with high yield and high selectivity. Finally, the yield of mixed diethylbenzene is ≥ 28wt%, and the selectivity of mixed diethylbenzene is ≥ 98wt%. At the same time, the reaction temperature is lower than that of the prior art, and the invention is suitable for the production of mixed diethylbenzene.

Description

The method that ethylbenzene and ethanol or ethylene are alkylated into mixed diethylbenzene

technical field

The invention relates to a synthesis method of mixed diethylbenzene, in particular to a method for synthesizing mixed diethylbenzene by alkylation of ethylbenzene and ethanol or ethylene, which belongs to the technical field of chemical industry.

Background technique

Mixed diethylbenzene, also known as mixed diethylbenzene, is an organic raw material. Mixed diethylbenzene refers to a mixture of p-diethylbenzene (PDEB for short) and m-diethylbenzene (MDEB for short). P-diethylbenzene is mainly used to produce p-xylene (referred to as PX) adsorption desorbent and p-divinylbenzene; mixed diethylbenzene is mainly used to produce divinylbenzene (referred to as DVB), and is also used for pharmaceutical intermediates and solvents.

At present, the domestic production methods of mixed diethylbenzene are all chemical synthesis methods: (1) polyethylbenzene is a by-product of benzene alkylation to ethylbenzene and styrene plant, and then rectified and separated to obtain mixed diethylbenzene; (2) using benzene Or the alkylation method of ethylbenzene and ethylene or ethanol, but the main disadvantage of this method is that the reaction temperature is relatively high, generally between 350 and 450°C, resulting in more by-products generated by the reaction, and the utilization rate of the alkylating agent Low catalyst life, frequent regeneration, high consumption of raw materials, low yield of mixed diethylbenzene, high production cost.

Although some progress has been made in the research of adsorption separation method, especially the product purity is not high, generally about 95-98%, which cannot meet the requirements of producing high-quality desorbent. Other methods for producing mixed diethylbenzene mainly include: ultra-distillation method, crystallization method, coordination method, etc. are all in the research and development stage.

CN113333014A discloses a kind of solid catalyst that is used for ethylphenylethanol/ethylene alkylation to make diethylbenzene, is that MgO is deposited on the strip nano HZSM-5 molecular sieve, the quality of described MgO and strip nano HZSM-5 molecular sieve The ratio is 0.5~6.0%. The preparation method is to immerse the strip-shaped nanometer HZSM-5 molecular sieve in the magnesium salt solution for 6-8 hours, take the solid and dry it at 80-120°C, and then roast it at 500-600°C for 4 hours in the air atmosphere. The magnesium salt is Mg At least one of (NO ₃ ) ₂ , Mg(CH ₃ COO) ₂ , MgCl ₂ and MgSO ₄ , the concentration of the magnesium salt solution is obtained by roasting MgO at 500~600°C for 4 hours and strip-shaped HZSM-5 molecular sieve The mass ratio of 0.5~6.0% shall prevail. The reaction temperature is 320-380°C, the conversion rate of ethylbenzene is ≥16wt%, the yield of mixed diethylbenzene is ≥15wt%, and the content of by-product benzene is up to 13.06wt%.

CN105381814 discloses a catalyst for the alkylation reaction of ethylbenzene and ethanol, which is made of the following raw materials in weight percentage: 10%-30% of alumina, 70%-90% of modified hydrogen-type eutectic ZSM-5/ZSM-11 molecular sieve %; Modified hydrogen ZSM-5/ZSM-11 molecular sieve is hydrogen ZSM-5/ZSM-11 molecular sieve modified by citric acid. In addition, the invention also discloses a preparation method of the catalyst, which comprises: (1) kneading the raw materials and then drying to obtain the mixture; (2) roasting the mixture in a water vapor atmosphere to obtain the catalyst. The catalyst of the present invention is used in the preparation of p-diethylbenzene by the alkylation reaction of ethylbenzene and ethanol, which can greatly suppress side reactions such as alkylation transfer while obtaining a relatively high conversion rate of ethylbenzene (ethanol), and improve the reaction efficiency. Product diethylbenzene or p-diethylbenzene selectivity.

CN107913727 discloses a method for preparing a catalyst for efficient alkylation of ethylbenzene to produce p-diethylbenzene, which belongs to the technical field of catalyst preparation. The method uses nano-hydrogen ZSM-5 molecular sieves mixed with binders and extrusion aids. During the kneading process, inorganic acid solutions and modified components of magnesium and phosphorus are added to mix and peptize. Catalyst stability, the catalyst is obtained by impregnating the modified component silicon in only one step. The pore size and the acidity of the outer surface of the molecular sieve in the catalyst are significantly improved under the synergistic modification of magnesium, silicon and phosphorus. Compared with the prior art, the modified components magnesium and phosphorus of the preparation method provided by the invention can be directly introduced during extrusion, which simplifies the preparation process and reduces the industrial production cost.

CN1605390 discloses a catalyst for the alkylation of ethanol and ethylbenzene to synthesize p-diethylbenzene and its preparation method. Based on H-ZSM-5 molecular sieve with a Si/Al ratio of 50, the surface acidity and pores of the catalyst are adjusted by B, Mg and Co. It has an ideal pore size distribution and acidity distribution in the pores and a high-efficiency anti-coking ability. Industrial catalyst for the synthesis of p-diethylbenzene. The precursor of B is boric acid, the precursor of Mg is magnesium nitrate, and the precursor of Co is cobalt nitrate. The mass ratio of B to H-ZSM-5 molecular sieve is 1% to 3%, the mass ratio of Mg to H-ZSM-5 molecular sieve is 0.1% to 1%, and the mass ratio of Co to H-ZSM-5 molecular sieve is 1% ~3%.

Its shortcoming is: the key technology of mixing diethylbenzene is the catalytic alkylation method of ethylbenzene and ethanol or ethylene, wherein the core technology is the activity and selectivity of the alkylation catalyst. Existing ZSM-5, hydrogen ZSM-5, Mg-ZSM-5 catalysts, etc. generally have problems such as high reaction temperature and low selectivity of mixed diethylbenzene.

Contents of the invention

The purpose of the present invention is to provide a method for the alkylation of ethylbenzene and ethanol or ethylene to synthesize mixed diethylbenzene, aiming to solve the existing problems in the synthesis of mixed diethylbenzene, so that the catalyst activity is high and the product yield can be improved. and optional purposes.

The object of the present invention is achieved like this: a kind of method of ethylbenzene and ethanol or ethylene alkylation synthesis mixed diethylbenzene, in reaction device, catalyst is loaded in fixed reaction bed, and reaction raw material is ethylbenzene and ethanol or ethylene , the reaction temperature is 280~320°C, the reaction pressure is 0.5Mpa~1.5MPa, the molar ratio of ethylbenzene to ethanol or ethylene is 10~14:1, and the weight space velocity is 0.5h-1; the catalyst is Mn@ZSM -5.

Further, the catalyst Mn@ZSM-5 is obtained through the following steps:

1) Mix manganese nitrate aqueous solution with ZSM-5 fine powder, heat and stir for 3-4 hours;

2) Heat and evaporate until it can be extruded into strips, after extrusion into strips, vacuum dry at 100-120°C for 2-3 hours;

3) Finally, the Mn@ZSM-5 catalyst was obtained after calcination in a muffle furnace at 550±10°C for 9-10 hours.

Preferably, in ZSM-5, the molar ratio of silicon to aluminum is 400:1.

Preferably, the mass ratio of manganese nitrate to ZSM-5 molecular sieve is 1:4~8.

Compared with the prior art, the beneficial effect of the present invention is that: the Mn@ZSM-5 catalyst adjusts the surface acid distribution and pores of the ZSM-5 molecular sieve through the Mn element, and obtains mixed diethylbenzene with high yield and high selectivity catalyst. Finally, the yield of mixed diethylbenzene is ≥ 28wt%, and the selectivity of mixed diethylbenzene is ≥ 98wt%. At the same time, the reaction temperature is lower than that of the prior art, and the invention is suitable for the production of mixed diethylbenzene.

Detailed ways

Example 1:

Weigh 16.67g of manganese nitrate and dissolve it in 300g of distilled water, then weigh 100g of ZSM-5 molecular sieve fine powder with a silicon-aluminum molar ratio of 400 and disperse it, mix, heat and stir for 3-4h; then heat and evaporate until it can be extruded into strips, and then After being formed into strips, vacuum-dry at 120°C for 2-3h; after drying, bake in a muffle furnace at 550±10°C for 9-10h to obtain a Mn@ZSM-5 molecular sieve catalyst.

The above Mn@ZSM-5 catalyst was loaded in a fixed reaction bed, the reaction temperature was 300°C, the reaction pressure was 1.0MPa, the molar ratio of ethylbenzene to ethanol was 12:1, and the weight space velocity was 0.5h ^-1 . The mixed diethylbenzene yield is 30.9wt%, and the mixed diethylbenzene selectivity is 99.4wt%.

Example 2-1:

Use "wherein the mass ratio of manganese nitrate and ZSM-5 is 1:4" instead, and the others are the same as in Example 1.

Example 2-2:

Use instead " wherein manganese nitrate and ZSM-5 mass ratio are 1:5, other are with embodiment 1.

Embodiment 2-3:

Use "wherein the mass ratio of manganese nitrate and ZSM-5 is 1:7" instead, and the others are the same as in Example 1.

Embodiment 2-4:

Use "wherein the mass ratio of manganese nitrate and ZSM-5 is 1:8" instead, and the others are the same as in Example 1.

Comparative example 2-a:

Use "wherein the mass ratio of manganese nitrate and ZSM-5 is 1:3" instead, and the others are the same as in Example 1.

Comparative example 2-b:

Use "wherein the mass ratio of manganese nitrate and ZSM-5 is 1:9" instead, and the others are the same as in Example 1.

Table 1 Comparison table of the effect of Mn loading on the yield and selectivity of mixed diethylbenzene

According to the comparative results in Table 1, as the Mn loading gradually decreases, the yield and selectivity increase first and then decrease. The mass ratio of manganese nitrate and ZSM-5 is preferably 1:4-8, preferably 1:6.

Example 3-1:

Use "reaction temperature is 280 DEG C" instead, other with embodiment 1.

Example 3-2:

Use "reaction temperature is 290 DEG C" instead, and others are the same as in Example 1.

Embodiment 3-3:

Use "reaction temperature is 310 DEG C" instead, other with embodiment 1.

Embodiment 3-4:

Use "reaction temperature is 320 DEG C " instead, other are the same as embodiment 1.

Comparative example 3-a:

Use "reaction temperature is 270 DEG C" instead, other with embodiment 1.

Comparative example 3-b:

Use "reaction temperature is 330 DEG C " instead, other are the same as embodiment 1.

Table 2 Comparison table of the influence of reaction temperature on the yield and selectivity of mixed diethylbenzene

According to the comparative results in Table 2, as the reaction temperature gradually increases, the yield and selectivity first increase and then decrease, and the reaction pressure is preferably 280-320°C, preferably 300°C.

Example 4-1:

Use "maintain reaction pressure at 0.5Mpa" instead, and others are with embodiment 1.

Example 4-2:

Use "maintain reaction pressure at 0.8Mpa" instead, and others are with embodiment 1.

Embodiment 4-3:

Use "maintain reaction pressure at 1.2Mpa" instead, and others are with embodiment 1.

Embodiment 4-4:

Use "maintain reaction pressure at 1.5Mpa" instead, and others are with embodiment 1.

Comparative example 4-a:

Use "maintain reaction pressure at 0.4Mpa" instead, and others are with embodiment 1.

Comparative example 4-b:

Use "maintain reaction pressure at 1.6Mpa" instead, and others are with embodiment 1.

Table 3 Comparison table of the influence of reaction pressure on the yield and selectivity of mixed diethylbenzene

According to the comparative results in Table 3, as the reaction pressure gradually increases, the yield and selectivity first increase and then decrease, and the reaction pressure is preferably 0.1-1.5MPa, preferably 1.0MPa.

Example 5-1:

Use "the mol ratio of ethylbenzene and ethanol is 10:1" instead, other with embodiment 1.

Example 5-2:

Use "the mol ratio of ethylbenzene and ethanol is 11:1" instead, other with embodiment 1.

Embodiment 5-3:

Use "the mol ratio of ethylbenzene and ethanol is 13:1" instead, and others are with embodiment 1.

Embodiment 5-4:

Use "the mol ratio of ethylbenzene and ethanol is 14:1" instead, other with embodiment 1.

Comparative example 5-a:

Use "the mol ratio of ethylbenzene and ethanol is 9:1" instead, other with embodiment 1.

Comparative example 5-b:

Use "the mol ratio of ethylbenzene and ethanol is 15:1" instead, other with embodiment 1.

Table 4 Comparison table of the influence of ethylbenzene and ethanol molar ratio on the yield and selectivity of mixed diethylbenzene

According to the comparative results in Table 4, as the molar ratio of ethylbenzene and ethanol increases gradually, the yield and selectivity first increase and then decrease, and it is better to adopt a molar ratio of 10-14:1, preferably 12:1.

Example 6-1:

Use "the mol ratio of ethylbenzene and ethylene is 10:1" instead, and others are the same as in Example 1.

Embodiment 6-2:

Use "the mol ratio of ethylbenzene and ethylene is 11:1" instead, other with embodiment 1.

Embodiment 6-3:

Use "the mol ratio of ethylbenzene and ethylene is 13:1" instead, other with embodiment 1.

Embodiment 6-4:

Use "the mol ratio of ethylbenzene and ethylene is 14:1" instead, other with embodiment 1.

Comparative example 6-a:

Use "the mol ratio of ethylbenzene and ethylene is 10:1" instead, and others are the same as in Example 1.

Comparative example 6-b:

Use "the mol ratio of ethylbenzene and ethylene is 14:1" instead, other with embodiment 1.

Table 5 Comparison table of the influence of the mass ratio of ethylbenzene and ethylene on the yield and selectivity of mixed diethylbenzene

According to the comparative results in Table 5, as the molar ratio of ethylbenzene and ethylene increases gradually, the yield and selectivity of mixed diethylbenzene increase first and then decrease. It is better to adopt a molar ratio of 10-14:1, preferably 12:1 .

Example 7-1

Change the molar ratio of silicon to aluminum to 300:1, and the others are the same as in Example 1.

Example 7-2

Change the molar ratio of silicon to aluminum to 200:1, and the others are the same as in Example 1.

Example 7-3

Change the molar ratio of silicon to aluminum to 500:1, and the others are the same as in Example 1.

Example 7-4

Change the molar ratio of silicon to aluminum to 600:1, and the others are the same as in Example 1.

Table 6 Comparison table of ZSM-5 silicon-aluminum molar ratio on the yield and selectivity of mixed diethylbenzene

According to the comparison results in Table 6, with the increase and decrease of the ratio of silicon to aluminum, the yield and selectivity of mixed diethylbenzene will decrease sharply, and the molar ratio of 400:1 is the best.

The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solutions disclosed in the present invention, those skilled in the art can make some replacements and modifications to some of the technical features without creative work according to the disclosed technical content. Deformation, these replacements and deformations are all within the protection scope of the present invention.

Claims (4)

1. A method for ethylbenzene and ethanol or ethylene alkylation to synthesize mixed diethylbenzene is characterized in that: in the reaction device, the catalyst is loaded in a fixed reaction bed, and the reaction raw materials are ethylbenzene and ethanol or ethylene, and the reaction temperature The temperature is 280~320°C, the reaction pressure is 0.5Mpa~1.5MPa, the molar ratio of ethylbenzene to ethanol or ethylene is 10~14:1, and the weight space velocity is 0.5h-1; the catalyst is Mn@ZSM-5. 2. the method for ethylbenzene and ethanol or ethylene alkylation synthesis mixed diethylbenzene according to claim 1, is characterized in that: described catalyst Mn@ZSM-5 is obtained by following steps: 1) Mix manganese nitrate aqueous solution with ZSM-5 fine powder, heat and stir for 3-4 hours; 2) Heat and evaporate until it can be extruded into strips, after extrusion into strips, vacuum dry at 100-120°C for 2-3 hours; 3) Finally, the Mn@ZSM-5 catalyst was obtained after calcination in a muffle furnace at 550±10°C for 9-10 hours. 3. The method for alkylating ethylbenzene with ethanol or ethylene to synthesize mixed diethylbenzene according to claim 2, characterized in that: in ZSM-5, the molar ratio of silicon to aluminum is 400:1. 4. The method for alkylating ethylbenzene with ethanol or ethylene to synthesize mixed diethylbenzene according to claim 2, wherein the mass ratio of manganese nitrate to ZSM-5 molecular sieve is 1:4~8.