Unlock instant, AI-driven research and patent intelligence for your innovation.

Method for producing mixed xylene by methylbenzene methylation

A technology of mixing xylene and methylation, which is applied in the direction of organic chemistry, condensation between hydrocarbons and non-hydrocarbons to produce hydrocarbons, etc. The effect of improving utilization rate, good technical effect, and improving catalyst life

Inactive Publication Date: 2014-05-07
CHINA PETROLEUM & CHEM CORP +1
View PDF5 Cites 8 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The toluene methylation catalyst uses a solid acid catalyst, and there is methanol raw material in the reaction system. Methanol is easy to decompose at a certain temperature to form impurities such as olefins. On the surface of the solid acid catalyst, olefins themselves are very easy to polymerize or react with The further polycondensation of aromatics in the material leads to carbon deposition, which covers the active sites on the surface of the catalyst and leads to catalyst deactivation
[0008] On the other hand, the toluene methylation reaction is an exothermic reaction, and the thermal effect of the reaction is very large. In a wide temperature range, although the thermodynamics of the main reaction is easy to carry out, the side reaction will increase if the temperature is too high, and the side reaction is more complicated. There are various reactions of aromatic hydrocarbon system, such as disproportionation, alkylation transfer, condensation, etc.; there are methanol side reactions, such as etherification, alkylation, aromatization, decomposition, etc.; also include side reactions between aromatic hydrocarbons and methanol, Such as aromatic ethylation, propylation and deep methylation reactions, etc.
resulting in a decrease in methyl utilization

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for producing mixed xylene by methylbenzene methylation
  • Method for producing mixed xylene by methylbenzene methylation
  • Method for producing mixed xylene by methylbenzene methylation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Take SiO 2 / Al 2 o 3 50g of hydrogen-type ZSM-5 molecular sieve with a molar ratio of 250, 21g of pseudoboehmite, and 1.5g of scallop powder were mixed for 20 minutes to obtain intermediate A. Take 15ml of nitric acid solution (mixing nitric acid with a mass concentration of 69% and water It is mixed according to the volume ratio of 1:1), and 1.4g magnesium oxide is dissolved in the nitric acid solution to obtain solution B, which is poured into A, kneaded and shaped, and roasted at 540°C for 5 hours to obtain a 1cm-long The strip catalyst C. C was treated with steam at 500°C for 2 hours to obtain a catalyst, which was designated as C1.

[0039] Four fixed bed reactors are connected in series. Each reactor adopts Φ2.54*60cm stainless steel tube, and is heated in three sections, and the temperature difference in the constant temperature section is less than ±1°C. The C1 catalyst is distributed in the constant temperature sections of four reactors, each reactor has t...

Embodiment 2

[0043] Adopt implementation 1 same method to prepare ZSM-5 molecular sieve catalyst, wherein SiO 2 / Al 2 o 3 The molar ratio is 350. Denote it as C2.

[0044] Get the C2 catalyst 40g and load the reactor in equal portions, and the reactor structure is the same as that of Example 1. The methylating reagent used was methanol. The number of reactors connected in series and the reaction conditions are shown in Table 1. The test results are shown in Table 2.

[0045]

Embodiment 3

[0047] Get C1 catalyst 40g and load the reactor in equal parts, and the reactor structure is identical with embodiment 1. The methylating agent used is dimethyl ether. The number of reactors connected in series and the reaction conditions are shown in Table 1. The test results are shown in Table 2.

[0048]

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention relates to a method for producing mixed xylene by methylbenzene methylation. The method mainly solves the technical problems that catalyst deactivation in methylbenzene methylation reaction is quicker and a methylbenzene conversion rate and a methyl utilization ratio are lower in the prior art. The method comprises the steps that a plurality of fixed bed reactors are connected in series; a preheated fresh methylbenzene raw material and a preheated fresh methylation reagent are supplied to the respective reactors; each reactor is filled with a methylbenzene methylation catalyst with same or different quantities; the reaction materials sequentially pass through bed sections under a certain technological condition; and flows flowing out of outlets of the fixed bed reactors except the last reactor flow into inlets of the next fixed bed reactors respectively. With the adoption of the technical scheme, the problems are solved better, so that the method can be used in industrial production of mixed xylene.

Description

technical field [0001] The invention relates to a method for producing mixed xylenes by methylating toluene. Background technique [0002] Mixed xylene is one of the important basic chemical raw materials, mainly containing four components: p-xylene, o-xylene, m-xylene and ethylbenzene. Mixed xylenes can be used as raw materials for solvents, aviation gasoline additives, pesticide paints, and printing inks; ortho-xylene and p-xylene can be further extracted through isomerization and adsorption separation processes, of which o-xylene is the product of phthalic anhydride An important raw material, p-xylene is an important raw material for synthetic polyester fibers, mainly used in the production of terephthalic acid (PTA) and dimethyl terephthalate, and its consumption exceeds that of other C8 aromatics. [0003] In recent years, the increase in demand for gasoline has limited the supply capacity of toluene, the main raw material for the production of mixed xylenes. Therefore...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/08C07C2/86
Inventor 宋曙光孔德金董骞李华英胡慧锋
Owner CHINA PETROLEUM & CHEM CORP