Method for separating m-ethyltoluene and p-ethyltoluene by extractive distillation

A technology for extractive distillation and p-toluene ethylbenzene, which is used in distillation purification/separation, organic chemistry, etc., can solve the problems of slow decomposition, low separation efficiency of m-ethyl benzene and p-toluene ethylbenzene, and increased solvent consumption, so as to improve the relative volatilization The effect of high purity, high product purity and high separation efficiency

Active Publication Date: 2012-11-28
CHINA PETROLEUM & CHEM CORP +1
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Problems solved by technology

[0003] Chinese patent CN101077849A discloses a method for extracting and rectifying separation of m-methylethylbenzene and p-methylethylbenzene, using dibutyl phthalate as the solvent for extracting and rectifying, but this solvent not only has a relatively high separation efficiency for m-methylethylbenzene and p-methylethylbenzene Low, and slowly decomposes at high temperature, resulting in increased solvent usage

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  • Method for separating m-ethyltoluene and p-ethyltoluene by extractive distillation
  • Method for separating m-ethyltoluene and p-ethyltoluene by extractive distillation
  • Method for separating m-ethyltoluene and p-ethyltoluene by extractive distillation

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Embodiment 1-4

[0026] Under the condition that the mixture weight ratio of solvent / m-methylethylbenzene and p-methylethylbenzene is 5 and 10, the extraction and rectification solvent benzonitrile and phenylacetonitrile have been tested as described above, and the experimental results of their relative volatility are listed in Table 1 .

Embodiment 5

[0033] The raw material is a mixture of m-methylethylbenzene and p-methylethylbenzene, which contains 70% (weight) of m-methylethylbenzene and 30% (weight) of p-methylethylbenzene. The separation process conditions of embodiment 5 and each stream are listed in table 2 and 3 respectively. The extraction and rectification solvent adopts phenylacetonitrile.

[0034] Such as figure 1 As shown, the raw material 1 containing the mixture of m-methylethylbenzene and p-methylethylbenzene enters the middle and lower part of the extractive distillation tower T1, and the circulating extractive distillation solvent 9 enters the extractive distillation tower T1 from the upper part, and is separated by extractive rectification, and distilled out from the top of the tower. Methylethylbenzene, after being cooled by the first cooler C1, a part flows into the top of the extractive distillation tower T1 as methylethylbenzene reflux 2, and another part then discharges as product mmethylethylbenze...

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Abstract

The invention discloses a method for separating m-ethyltoluene and p-ethyltoluene by extractive distillation. The extractive distillation solvent adopted by the method is a nitrogenous compound, preferably cyanobenzene or benzyl cyanide, and more preferably benzyl cyanide. The method comprises the following steps: introducing an m-ethyltoluene/p-ethyltoluene mixture from the middle of the extractive distillation tower, and introducing an extractive distillation solvent from the tower top; and after carrying out extractive distillation, discharging the m-ethyltoluene from the top of the extractive distillation tower, discharging the rich solvent containing rich p-ethyltoluene from the tower bottom, sending the rich solvent into a solvent recovery tower, discharging the p-ethyltoluene from the top of the recovery tower, and recycling the extractive distillation solvent discharged from the bottom of the recovery tower. The invention has the advantages of low operation energy consumption and high product purity; and the solvent adopted by the method can obviously improve the relative volatility between m-ethyltoluene and p-ethyltoluene, is easy to recycle, and has high chemical thermal stability.

Description

technical field [0001] The invention relates to the field of chemical industry, and furthermore, relates to a method for extracting and rectifying separation of m-methylethylbenzene and p-methylethylbenzene. Background technique [0002] The catalytic dehydrogenation of p-methylethylbenzene can produce p-methylstyrene. p-methylstyrene is the monomer used to produce polymethylstyrene (PPMS). PPMS has a lower density than polystyrene (PS), less volume shrinkage during polymerization, high heat-resistant temperature, and easy molding and processing. Moreover, PPMS has elasticity, Transparency, melt fluidity, etc. are higher than polystyrene (PS). At present, the price of PPMS in the foreign market is about 30% higher than that of PS, and it is gradually replacing PS; m-methylethylbenzene is also an important basic organic chemical raw material, which is widely used in chemical production. The bottom oil of the xylene tower in the reforming unit of the refinery contains about ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C15/02C07C7/08
Inventor 冯海强朱跃辉高继东赵开径鲁耘
Owner CHINA PETROLEUM & CHEM CORP
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