CN1443741A

CN1443741A - Method for producing potassium methoxide

Info

Publication number: CN1443741A
Application number: CN 02110174
Authority: CN
Inventors: 孙宝远; 张炳胜; 陈衍军; 周树新; 武峰
Original assignee: FEICHENG ASIDE CHEMICAL ENGINEERING Co Ltd
Current assignee: FEICHENG ASIDE CHEMICAL ENGINEERING Co Ltd
Priority date: 2002-03-13
Filing date: 2002-03-13
Publication date: 2003-09-24
Anticipated expiration: 2022-03-13
Also published as: CN1186302C

Abstract

The method for producing potassium methylate by using methyl alcohol and potassium hydroxide as main raw material includes the following steps: adding potassium hydroxide and methyl alcohol into potassium methylate reactor according to a certain molecular weight ratio, stirring, controlling, reaction temp., continuously introducing dried methyl alcohol from bottom portion of the reactor, adsorbing the water produced by reaction to form high water-content methyl alcochol, feeding the high water-content methyl alcohol into the rectifying equipment to make rectificatino and dehydration and form dried methyl alcohol, then feeding it into potassium methylate reactor, implementing circulation of the methyl alcohol, and its rectifying equipment can utilize the azeotropic rectifying equipment.

Description

Method for producing potassium methoxide

One, the technical field

The invention relates to a method for producing potassium methoxide by using methanol and potassium hydroxide as main raw materials.

Second, background Art

The potassium methoxide is a novel high-efficiency organic and fine chemical catalyst, can be used as a shrinkage agent and a catalyst, and is used for preparing products such as methyl formate, dimethylformamide, dimethyl carbonate and the like; can also be used as intermediate of medicine and pesticide for preparing vitamin B₁Medicaments and pesticides such as vitamin A, sulfadiazine and the like; can also be used as catalyst for treating edible fat and edible oil; can also be used as analytical reagent, etcHas wide application.

At present, two process methods exist for producing potassium methoxide products; one is a 'metallic potassium method', which has the serious disadvantages of poor safety, easy explosion and the like in production, and has higher production cost due to the factors of expensive metallic potassium, difficult transportation, difficult storage and the like, and the method tends to be eliminated gradually. The other is to react methanol with potassium hydroxide to produce potassium methoxide. The potassium methoxide is prepared by reacting potassium hydroxide with methanol in the presence of oxide as a dehydrating agent and a surfactant abroad. The method has the defects of long flow, more equipment, troublesome operation and the like, and waste residues are also generated in the production. Enterprises try to produce potassium methoxide by using potassium hydroxide in China, and the problem of methanol dehydration can be solved only by operating expensive methanol dehydration equipment, so that the production cost is greatly increased, and the enterprises do not put into production. Therefore, the domestic required potassium methoxide products mainly depend on import or only can use sodium methoxide with poor effect as a substitute.

Third, the invention

The invention aims to provide a method for producing potassium methoxide, which has the advantages of simple process flow, convenient operation, reduced equipment investment and low cost, and takes methanol and potassium hydroxide as main raw materials to react under certain conditions to prepare potassium methoxide, wherein the reaction equation is as follows:

meanwhile, water generated by the reaction is taken away by the dry methanol to form high-water-content methanol, then the high-water-content methanol is rectified and dehydrated by a rectifying device, the rectifying device can utilize the existing azeotropic rectifying device of an enterprise, and the high-water-content methanol forms the dry methanol after rectification and dehydration and then enters a potassium methylate reactor, and the process is circulated in such a way that the rectifying temperature of the rectifying device is only controlled due to the fact that the boiling point of the methanol is different from the boiling point of the secondary chemical products.

The process comprises the following steps:

adding metered potassium hydroxide and methanol into a potassium methoxide reactor, wherein the adding amount ratio of the potassium hydroxide to the methanol is the molecular weight ratio of the potassium hydroxide to the methanol, starting a stirring device of the potassium methoxide reactor, simultaneously heating the potassium methoxide reactor, controlling the reaction temperature to be 94-104 ℃, controlling the reaction pressure to be normal pressure, continuously introducing dry methanol from the bottom of the potassium methoxide reactor, adsorbing water generated in the reaction of the methanol and the potassium hydroxide by the dry methanol to form high-water-content methanol, continuously discharging the high-water-content methanol from the potassium methoxide reactor, and feeding the high-water-content methanolinto a rectifying device for rectifying and dehydrating to form the dry methanol. And then introducing the rectified and dehydrated dry methanol into a potassium methoxide reactor to realize the circulation of the methanol until the potassium methoxide in the potassium methoxide reactor is completely reacted to prepare potassium methoxide, and then sending the prepared potassium methoxide into a product storage tank for users to use. The rectification apparatus may be of an azeotropic type.

The invention continuously introduces dry methanol into the potassium methoxide reactor, and the dry methanol is used for absorbing water generated when the methanol reacts with the potassium hydroxide to prepare the potassium methoxide, so that high-water-content methanol is formed, the quality of the potassium methoxide is ensured, meanwhile, the rectification device for producing secondary chemical products by enterprises can be used for rectifying and dehydrating the high-water-content methanol, and the prepared dry methanol is introduced into the potassium methoxide reactor for recycling. When the high-water-content methanol is rectified and dehydrated in the azeotropic rectifying device, the methanol can be rectified with the secondary chemical products in the azeotropic rectifying device at the same time by utilizing the difference between the boiling point of the methanol and the boiling point of the secondary chemical products, so that the high-water-content methanol can be co-produced with the secondary chemical products, the investment of the methanol rectifying device is saved, and the rectifying cost of the methanol is reduced. Therefore, the method has the characteristics of simple process flow, convenient operation, reduced equipment investment, low cost and the like, and can realize the co-production with secondary chemical products.

Fourth, detailed description of the invention

Adding metered flake potassium hydroxide from a feed inlet at the upper part of a potassium methoxide reactor, and adding metered methanol from the bottom of the potassium methoxide reactor, wherein the adding amount ratio of the methanol to the potassium hydroxide is the molecular weight ratio, namely the ratio of the methanol to the potassium hydroxide is 32: 56. After the methanol is fed, a stirrer of the potassium methoxide reactor is started to stir, jacket steam is started simultaneously to heat the interior of the potassium methoxide reactor, the reaction temperature is controlled to be 100 +/-2 ℃, a pressure control valve of the potassium methoxide reactor is opened to enable the reaction pressure to be at normal pressure, then water generated in the reaction is continuously and uniformly added from the bottom of the potassium methoxide reactor, and is absorbed by dry methanol to form high-water-content methanol which is discharged from the upper part of the potassium methoxide reactor and enters the existing formic acid rectifying device of an enterprise to be rectified and dehydrated, and the boiling point of the methanol is 64.7 ℃ and the boiling point of the formic acid is 100.6 ℃, so that the methanol is rectified and separated from a first rectifying tower in the formic acid rectifying device to prepare the dry methanol, and the dry methanol and the formic acid are co-produced, thereby greatly reducing the cost for preparing the dry methanol. Then the prepared dry methanol is introduced into the potassium methoxide reactor for recycling. And (3) completely preparing potassium methoxide till the potassium hydroxide in the potassium methoxide reactor is reacted, then sending the potassium methoxide into a product storage tank, and filling according to the requirements of users for users to use.

The invention continuously introduces dry methanol into the potassium methoxide reactor, adsorbs water generated by the reaction to form high-water-content methanol, and then utilizes the constant boiling type rectifying device of the enterprise, does not need to invest in building a methanol rectifying device, and realizes co-production with the secondary chemical products, thereby greatly reducing the rectifying cost of the methanol and further reducing the cost for producing the potassium methoxide.

Claims

A method for producing potassium methoxide takes methanol and potassium hydroxide as main raw materials, and is characterized in that the method comprises the following technological processes: adding metered potassium hydroxide and methanol into a potassium methoxide reactor, wherein the adding amount ratio of the potassium hydroxide to the methanol is the molecular weight ratio of the potassium hydroxide to the methanol, starting a stirring device of the potassium methoxide reactor, simultaneously heating the potassium methoxide reactor, controlling the reaction temperature to be 94-104 ℃, controlling the reaction pressure to be normal pressure, continuously introducing dry methanol from the bottom of the potassium methoxide reactor, adsorbing water generated in the reaction of the methanol and the potassium hydroxide by the dry methanol to form high-water-content methanol, continuously discharging the high-water-content methanol from the potassium methoxide reactor, and introducing the high-water-content methanol into a rectifying device for rectifying and dehydrating to form dry methanol, and then introducing the dehydrated dry methanol into the potassium methoxide reactor to realize the circulation of the methanol until all potassium hydroxide in the potassium methoxide reactor is completely reacted to prepare potassium methoxide; the rectification apparatus may be of an azeotropic type.