CN1045586C

CN1045586C - Process for producing chloro-ether

Info

Publication number: CN1045586C
Application number: CN95106939A
Authority: CN
Inventors: 钱萍; 张云钗
Original assignee: CHENGUANG CHEMICAL COMPREHENSIVE UTILIZATION FACTORY HANGZHOU CITY
Current assignee: CHENGUANG CHEMICAL COMPREHENSIVE UTILIZATION FACTORY HANGZHOU CITY
Priority date: 1995-06-16
Filing date: 1995-06-16
Publication date: 1999-10-13
Anticipated expiration: 2015-06-16
Also published as: CN1138568A

Abstract

The present invention relates to a process for producing chloromethyl ether, which is mainly applied to the fields of chemical industry and medicine. In the process, hydrochloric acid gas produced in a production process of chloroparaffin is introduced into a solution of methylal and formaldehyde (or a solution of methyl alcohol and formaldehyde) through a buffer tank for reaction; then, the solution is settled and delaminated, and a lower acid layer and an upper chloromethyl ether layer are separated. The process has the advantages of no need of concentrated sulphuric acid and hydrochloric acid, fewer devices, low production cost and no environmental pollution.

Description

Process for producing chloromethyl ether

The invention relates to a production method of chloromethyl ether, which is mainly used for producing anion exchange resin in the chemical field and producing sulfadiazine drugs in the medical field.

The production process flow of chloromethyl ether in the prior art is shown in figure 1, industrial hydrochloric acid is added into a hydrogen chloride generating kettle, concentrated sulfuric acid is dripped at the temperature of 70 ℃ for reaction, then hydrogen chloride gas generated by the reaction is introduced into a reaction kettle filled with methanol and formaldehyde solution for chlorination synthesis, the reaction temperature is controlled between 15 ℃ and 47 ℃, when the chlorine content is measured to reach below 40% -43% after the hydrogen chloride is absorbed by the reaction, the chlorination reaction is finished, and the chemical reaction equation is as follows:

standing for one hour, collecting the upper layer of synthesized chloromethyl ether and the lower layer of acid layer of dilute sulfuric acid, small amount of hydrochloric acid, unreacted methanol and formaldehyde, and recovering the lower acid layer in a distillation kettle via the bottom of the kettle while controlling via a sight glass tube at the bottom of the kettle. Thus, only chloromethyl ether is left in the reaction kettle finally, and the materials can be packaged and discharged. Meanwhile, the acid layer solution in the distillation recovery kettle is recycled by introducing water vapor into the distillation recovery kettle for heating, and the recycled methanol serving as a raw material can be put into a chlorination reaction kettle for reaction. The production process of chloromethyl ether has the following disadvantages in the practical use: 1. the used hydrogen chloride reaction kettle has more equipment, consumes a large amount of concentrated sulfuric acid and hydrochloric acid, and has high production cost; 2. the residual waste acid (mainly dilute sulfuric acid containing a small amount of hydrochloric acid) after the reaction of concentrated sulfuric acid and hydrochloric acid to generate hydrogen chloride gas is difficult to treat, thereby causing environmental pollution.

The invention aims to overcome the defects in the prior art and provide a method for producing chloromethyl ether, which can fully and comprehensively utilize the chloromethyl ether, does not need to consume concentrated sulfuric acid andhydrochloric acid, has low production cost and is easy to protect the environment.

The purpose provided by the invention can be realized by the following technical scheme: putting paraffin oil into a reaction kettle, introducing water vapor into the reaction kettle to heat the paraffin oil to 70-120 ℃, then introducing chlorine gas into the reaction kettle, controlling the optimal reaction temperature in the reaction kettle to be 90-120 ℃, introducing the generated hydrogen chloride gas and unreacted free chlorine into a pre-chlorination reaction kettle filled with the paraffin oil, introducing the hydrogen chloride gas into a chlorination reaction kettle filled with methylal and formaldehyde solution through a hydrogen chloride buffer tank to perform chlorination, controlling the reaction temperature to be 15-47 ℃, then standing and layering, and separating the acid layer solution at the lower layer from the chloromethyl ether at the upper layer.

The purpose provided by the invention can be realized by the following technical scheme: the methylal is replaced by methanol.

The drawings illustrate the following:

FIG. 1 is a process flow diagram of chloromethyl ether in the prior art.

FIG. 2 is a process flow diagram of the present invention.

The present invention will be further described below by way of examples.

Referring to fig. 2, the hydrogen chloride gas generated in the production process of chlorinated paraffin is introduced into methylal and formaldehyde solution for reaction after passing through a buffer tank, or is introduced into methanol and formaldehyde solution for reaction to generate chloromethyl ether. The paraffin oil is put into a chlorination reaction kettle, water vapor is introduced into a jacket of the reaction kettle to heat the paraffin oil to 70-120 ℃, then chlorine is introduced into the reaction kettle to carry out chlorination reaction, the optimal reaction temperature control degree in the reaction kettle is controlled to be 90-120 ℃, and the chemical reaction equation is as follows:

(composition of Paraffin oil is C₁₂H₂₆-C₂₈H₃₈A mixture of (1), C in the above chemical reaction formula₁₅H₃₂Is the average composition thereof). After the chlorination reaction, two parts are separated: firstly, stopping introducing chlorine when the chlorine content reaches 50 +/-2%, putting the chlorination finished liquid into a refining kettle (or a chlorination reaction kettle) for refining, namely introducing dry air for blowing acid, controlling the acid value to be within a specified index, and then adding a light-heat stabilizer for refining to obtain a chlorinated paraffin finished product. The second part is that after chlorination reaction, gas (hydrogen chloride gas and unreacted free chlorine) from the chlorination reaction kettle is introduced into a pre-chlorination reaction kettle filled with paraffin oil, the free chlorine is absorbed and reacted by the paraffin oil, the hydrogen chloride gas passes through a hydrogen chloride gas buffer tank and then is introduced into a chlorination reaction kettle filled with methylal (a reaction product of methanol and formaldehyde) and formaldehyde solution for chlorination synthesis, and of course, here, the hydrogen chloride gas from the buffer tank can also be introduced into the chlorination reaction kettle filled with methanol and formaldehyde solution for chlorination synthesisControlling the reaction temperature in the kettle between 15 ℃ and 47 ℃, and stopping introducing hydrogenchloride gas after the chlorination reaction is finished when the chlorine content is measured to be below 40% -43% after the reaction absorbs the hydrogen chloride. The chemical reaction equation is as follows:

or

Then standing for layering for about one hour, wherein the upper layer is synthesized chloromethyl ether, the lower layer is an acid layer which mainly comprises hydrochloric acid, unreacted methanol and formaldehyde, then putting the acid layer liquid of the lower layer into a distillation recovery kettle through the bottom of the reaction kettle, controlling layering through a sight glass tube arranged at the bottom of the kettle, and discharging and packaging the chloromethyl ether in the kettle after the acid layer liquid of the lower layer is completely discharged. To put inThe acid layer solution in the distillation recovery kettle can be distilled and recovered by introducing steam into a jacket of the reaction kettle and heating. The methanol recovered from the acid layer can be used as a raw material and then put into a chlorination reaction kettle for chlorination synthesis.

Compared with the prior art, the invention has the following advantages: 1. a large amount of concentrated sulfuric acid and hydrochloric acid are not needed to be consumed to generate hydrogen chloride gas, but the hydrogen chloride gas generated in the chlorinated paraffin production process is introduced into methylal (or methanol) and formaldehyde solution through a buffer tank to react to generate chloromethyl ether, so that tail gas is fully and comprehensively utilized, and the environment is protected. 2. The investment of the used equipment and equipment, such as storage tanks and metering tanks of concentrated sulfuric acid and hydrochloric acid, dilute sulfuric acid treatment equipment and the like, is reduced. 3. The process flow is simple, the production cost is greatly reduced, the production cost can be reduced by more than two thousand yuan by only using sulfuric acid and hydrochloric acid consumed by each ton of chloromethyl ether products, and the economic benefit is obvious.

Claims

1. A process for preparing chloromethyl ether includes such steps as putting paraffin oil in reactor, introducing water vapor to heat paraffin oil to 70-120 deg.C, introducing chlorine gas to reactor, introducing the generated hydrogen chloride gas and unreacted free chlorine to the prechlorination reactor containing paraffin oil, introducing the hydrogen chloride gas to the chlorination reactor containing methylal and formaldehyde solution for chlorination, controlling reaction temp at 15-47 deg.C, laying aside, and separating the acid layer solution from the chloromethyl ether.

2. The process for producing chloromethyl ether according to claim 1, characterized in that: the methylal is replaced by methanol.