Potassium hydroxide can be obtained by electrolysis of high purity aqueous potassium chloride solution. The type of electrolyzer used and the production process are similar to sodium hydroxide. When the diaphragm electrolyzer is used, the obtained electrolyte contains 10% - 15% (mass) potassium hydroxide and about 10% (mass) potassium chloride. After evaporation, concentration and cooling, most of the potassium chloride crystallizes and precipitates. After separation, the product containing 45% - 50% potassium hydroxide (containing 0.6% potassium chloride) is obtained. High purity potassium hydroxide can be produced by mercury electrolysis, but the content of heavy metal impurities in the aqueous solution of potassium chloride should be controlled below 0.1ppm to avoid high hydrogen content in chlorine gas. Special ion exchange membrane must be used for the ion-exchange membrane electrolysis. Potassium hydroxide is more difficult to dehydrate than sodium hydroxide. The purity of industrial solid potassium hydroxide is 88% - 92%. There are two kinds of solid: block and sheet. Liquid potassium hydroxide has two concentration specifications of 45% and 50%.
是基础化学工业中的重要产品，主要用作钾盐和钾碱的生产原料，在医 药、轻工业、电化工、纺织等领域也有广泛应用。应用举例如下：一种以甲苯作为反应的缓冲剂，用氢氧化钾作催化剂将甲基环硅氧烷在一定温度和压力 的条件下进行开环聚合，再用硫酸进行水解中和，最后减压脱去甲苯制 得粘度为20～40CS，羟基含量在2～12％以上的小分子羟基硅油。本发 明的用氢氧化钾催化合成小分子羟基硅油的方法采用甲基环硅氧烷为 原料，以甲苯作为反应缓冲剂，用氢氧化钾作催化剂，硫酸作中和剂在 水中进行开环聚合，(1)原材料的组分质量份配比为：甲基环硅氧烷为100 质量份、氢氧化钾10～70质量份、甲苯70～120质量份、硫酸8.5～60 质量份；(2)工艺控制条件：反应温度100～150℃、反应时间2～7小时、 水解温度30～70℃、水解时间1～3小时、搅拌转速大于70转/分钟。
Potassium hydroxide is an important product in the basic chemical industry. It is mainly used as raw material for the production of potash and potash. It is also widely used in medicine, light industry, electrochemistry, textile and other fields. The application examples are as follows: a kind of small molecular hydroxy silicone oil with viscosity of 20-40cs and hydroxyl content of more than 2-12% was prepared by using toluene as buffer, potassium hydroxide as catalyst, methyl cyclosiloxane as ring opening polymerization under certain temperature and pressure, sulfuric acid as hydrolysis neutralization, and finally toluene was removed under reduced pressure. The method for synthesizing small molecular hydroxyl silicone oil by catalysis of potassium hydroxide adopts methylcyclosiloxane as raw material, toluene as reaction buffer, potassium hydroxide as catalyst, sulfuric acid as neutralizer to conduct ring opening polymerization in water, (1) the mass ratio of the components of the raw material is 100 Mass fraction, potassium hydroxide 10-70 mass fraction, toluene 70-120 mass fraction, sulfuric acid 8.5-60 mass fraction; (2) process control conditions: reaction temperature 100-150 ℃, reaction time 2-7 hours, hydrolysis temperature 30-70 ℃, hydrolysis time 1-3 hours, stirring speed greater than 70 rpm.
Method 1: potassium hydroxide was produced by ion-exchange membrane. The production system of ion-exchange membrane potassium hydroxide is composed of primary brine refining, secondary brine refining, light brine dechlorination, hydrogen chloride treatment system and evaporation concentration system. The raw materials for the production of ionic membrane liquid alkali mainly include saturated refined brine, hydrochloric acid, Koh, chelating resin, pure water, potassium sulfite, and adhesives and anti adhesives for rubber pad fixation.
Method 2: a preparation method of high-purity potassium hydroxide product includes the following steps:
(1) The industrial potassium hydroxide is dissolved in ultra pure water, and the impurities are removed by stirring filtration;
(2) Continue to add complexing agent into filtrate, freeze and keep liquid state to produce water and potassium hydroxide crystal;
(3) Collect the crystal of hydrated potassium hydroxide, take it for heating and dissolving to get high-purity potassium hydroxide solution product, while under the protection of inert gas heating and drying to get high-purity solid potassium hydroxide production