Method for preparing cyclopentane refrigerant

Abstract

The invention belongs to the technical field of chemicals and discloses a method for preparing a cyclopentane refrigerant. Efficient separation of cyclopentane from 2,2-dimethyl butane is achieved byusing an extraction distillation technique with acetonitrile as an extraction agent. The method for preparing the cyclopentane refrigerant comprises the following steps: by taking a C5 mixture as a raw material, carrying out light component desorption, heavy component desorption, extraction distillation and desorption; by taking acetonitrile as an extraction agent, feeding a material from the topof a heavy component desorption tower into the middle part of an extraction distillation tower; feeding the extraction agent into the upper part of the extraction distillation tower, collecting 2,2-dimethyl butane from the top of the tower, and desorbing an enriched solvent at the bottom of the tower in a desorption tower, thereby obtaining the cyclopentane refrigerant. By adopting the method forpreparing the cyclopentane refrigerant, the obtained cyclopentane has purity not less than 99%, and is low in water content. The extraction agent is good in stability, high in selectivity, low in solvent ratio, low in boiling point, simple in process procedure, high in operation controllability, low in energy consumption, high in product purity, possible in extraction agent circulation, small in pollution and applicable to industrial production. The method is applicable to preparation of high-quality cyclopentane, and is particularly applicable to preparation of cyclopentane refrigerants of environmental-friendly refrigerators.

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. In the C5 mixed raw material, the main substance that affects the purity of the cyclopentane product is 2,2-dimethylbutane, so the key point of the problem is the separation of cyclopentane and 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 through ordinary distillation. In industry, the extraction method is commonly used to separate near-boiling systems. The extraction method requires experimental scree...

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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.

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