[K12 Supply and Sales] Overview of production methods of sodium lauryl sulfate

Sodium lauryl sulfate (K12) is white or light yellow powder or liquid with a slight grease smell. Easily soluble in water, it can reduce the surface tension of aqueous solutions and emulsify oils and fats. It is not sensitive to alkali and hard water, and has good compatibility with anions and non-ions. This product is flammable, irritating, and sensitizing. It is flammable when exposed to open flames and high heat. It decomposes when heated to release toxic gases.

The production method of sodium lauryl sulfate is as follows:

1. Put 9.5ml glacial acetic acid into a dry reaction bottle in a fume hood, fully cool it in an ice bath, add 3.5ml (0.053mol) chlorosulfonic acid, and mix evenly. Slowly add 8g (0.043mol) of dodecanol in liquid form or very fine solid powder form to cold acetic acid and chlorosulfonic acid over 5 minutes, and stir for 30 minutes until all the alcohol is dissolved and participates in the reaction. If the alcohol is not completely dissolved, remove the reaction bottle from the ice bath and stir at room temperature for 10 minutes. Pour the reaction mass into a beaker containing 30g of crushed ice, add 30ml of n-butanol to the above mixture, and stir for 3 minutes. Slowly add 3 ml of saturated sodium carbonate aqueous solution while stirring. The solution will be alkaline to litmus paper. When the reaction becomes alkaline, add 10g solid anhydrous sodium carbonate and let it stand. Pour the upper n-butanol solution from the surface of the water layer into the beaker. Then add 20ml n-butanol to the water layer, stir thoroughly, and separate the n-butanol layer. Combine the n-butanol obtained twice, pour it into a separatory funnel and separate the water layer. Pour the n-butanol solution into the beaker, evaporate the n-butanol, and obtain a white residue, which is sodium lauryl sulfate.

2. The sulfur trioxide method reaction device is a vertical reactor. Nitrogen was introduced into the reactor through the gas vent at 32°C. The nitrogen flow rate is 85.9L·min. Pour in lauryl alcohol at 82.7kPa, with a flow rate of 58g·min. The liquid sulfur trioxide is passed into the flash evaporator at 124.1kPa, the flash evaporation temperature is maintained at 100°C, and the sulfur trioxide flow rate is controlled at 0.9072kg·h. Then, the sulfation product is quickly quenched to 50°C, put into the aging device, and left for 10 to 20 minutes. Finally, put it into the neutralization kettle and neutralize it with alkali. The neutralization temperature is controlled at 50°C, and when the pH value reaches 7 to 8.5, the material is discharged to obtain the finished liquid product. The solid product is obtained by spray drying.

3. Add 62g of lauryl alcohol to a 250ml four-necked flask equipped with a hydrogen chloride absorption device, a thermometer, an electric stirrer and a dropping funnel, and control the temperature to 25 ℃, use a dropping funnel to slowly add 24 ml of chlorosulfonic acid within 30 minutes under full stirring. The temperature should not exceed 30 ℃ during the dropwise addition. Pay attention to foaming and do not let the material overflow. After adding chlorosulfonic acid, react at 30°C for 2 hours. The hydrogen chloride gas generated during the reaction is absorbed with 5% mass fraction sodium hydroxide solution. After the sulfation is completed, slowly pour the sulfate into a mixture of 100g ice and water (ice: water = 2:1), while stirring thoroughly, and cool it with an ice-water bath outside. Finally, use a small amount of water to wash out all the reactants in the four-necked flask. After dilution is even, dropwise add 30% mass fraction sodium hydroxide solution under stirring to neutralize until the pH is 7-8.5. Then use n-butanol for extraction, and evaporate the n-butanol.