Separation method of cyclopentane and 2,2-dimethyl butane

Abstract

The invention belongs to the technical field of chemical engineering. Efficient separation of cyclopentane and 2,2-dimethyl butane is realized by adopting an extractive distillation technology takingacetonitrile as an extracting agent. The cyclopentane / 2,2-dimethyl butane separation method adopts an extractive distillation process, which comprises an extractive distillation process and a desorption process; acetonitrile is used as an extraction agent, a cyclopentane / 2,2-dimethyl butane mixture is fed into the middle of an extractive distillation column in the extractive distillation process,the extraction agent is fed into the upper part of the extractive distillation column, the working pressure of the extractive distillation column is 102-120 kPa, the solvent ratio is 6-9, the reflux ratio is 45-70, and the column bottom temperature is 70-80 DEG C. The 2,2-dimethyl butane is obtained from the top of the column, and a rich solvent at the bottom of the column is subjected to desorption through a desorption column to obtain cyclopentane. The separation method is good in separation effect and high in cyclopentane purity (not less than 99%); the extraction agent is good in stability, high in selectivity, low in solvent ratio and low in boiling point. The method is simple in process flow, high in operation controllability and low in energy consumption; the extraction agent can berecycled, is low in pollution and is suitable for industrial production. The method is suitable for preparing high-quality cyclopentane.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and relates to material separation and purification technology, in particular to the separation technology of cyclopentane. Background technique [0002] Cyclopentane is an environmentally friendly refrigerant that can be used to replace chlorofluorocarbons. It is also an excellent polyurethane foaming agent with a good market prospect. The main substance that affects the purity of cyclopentane products is 2,2-dimethylbutane. The cyclopentane / 2,2-dimethylbutane system is a near-boiling system with a difference of only 0.4°C in boiling points. It is difficult to obtain more than 99% cyclopentane monomer. In industry, the extraction method is commonly used to separate near-boiling systems. The extraction method requires experimental screening of extractants to improve the solubility of certain components in the system, while the solubility of other components is as low as possible. Extra...

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Problems solved by technology

The extraction process requires a high ratio of solvent to oil, and the extraction agent is easy to deteriorate. The deteriorated extraction agent is not regenerated, resulting in a large waste of solvent, serious pollution, high environmental pressure, and high energy consumption.

[0004] Chinese patent CN201510532233.0 reports a method for separating cyclopentane and 2,2-dimethylbutane, which is realized by utilizing the azeotropic characteristics of 2,2-dimethylbutane and dichloromethane The separation of cyclopentane and 2,2-dimethylbutane does not consider that cyclopentane and dichloromethane will also form a binary azeotrope, so it is necessary to strictly control cyclopentane, 2,2-dimethylbutane The ratio of alkane and dichloromethane has a narrow operable range. If the composition of raw materials changes slightly, cyclopentane and 2,2-dimethylbutane may not be separated, which is not suitable for industrial production.