Sodium p-toluenesulfonate CAS 657-84-1

The environmentally friendly production method for preparing sodium p-toluenesulfonate from waste sulfuric acid comprises the following steps:

1. In the 500-milliliter there-necked flask installed with thermometer, azeotropic distillation condenser, dropping funnel, add 217.8 parts of waste sulfuric acid produced after the dehydration of hydrochloric acid of content 45% to prepare hydrogen chloride gas, concentrate to content 75%, the remaining About 131 parts; 117 parts of toluene with a content of 99% were added dropwise at 110°C under stirring, and the dropwise addition time was 1.5 hours; after the dropwise addition, the reflux was maintained at 110°C and the water was separated from the water outlet of the oil-water separator at the same time. , the toluene is refluxed into the there-necked flask; when the water separation volume reaches 45 ml, the reaction ends, and the reaction time is 6 hours; continue to heat, distill and reclaim excess toluene, and stop collecting toluene when the temperature in the reactor reaches 140 ° C; the collected The weight of toluene is 24.4 grams, and the content is 95.9%;
2. After the reaction system is cooled to below 70 ℃, the sodium hydroxide aqueous solution that the weight percent concentration is 30% is slowly added dropwise to the reactor under stirring to carry out neutralization reaction, neutralized to PH=8, sodium hydroxide The dosage of the aqueous solution is 148 grams; during the neutralization process, the temperature is maintained at 70-90 ° C, and the stirring is continued for 15 minutes after the addition of the aqueous sodium hydroxide solution;
3. Add 2 grams of powdered activated carbon, stir at 85-90 ° C for 30 minutes, heat to boiling, steam 45 grams of water; then filter while hot, the filter cake is activated carbon and by-product sodium sulfate and a small amount of sodium p-toluenesulfonate product The filtrate was transferred into the beaker, crystallized by cooling, suction filtration, washed with 15 grams of ice water and dried to obtain 193.5 grams of sodium p-toluenesulfonate with an active content of 79.5%, yield 79.3%; 68.5 grams of mother liquor, active The material content is 41.5%, the conversion yield is 14.7%, and the total total yield is 94%.

A BHT production neutralization wastewater, wherein the content of sodium p-toluenesulfonate is 19.8%, and the content of alkali neutralizer (alkali containing sodium ions) is 3.7%. The concrete steps utilizing this neutralization wastewater to produce sodium p-toluenesulfonate include:

Add an appropriate amount of pH adjuster (p-toluenesulfonic acid) to the pH adjustment kettle to adjust the pH value of the neutralized wastewater to 6 to 7, then the pump is transferred to the decolorization kettle, and activated carbon is added to the decolorization kettle and heated to 80 to 90 ° C. After stirring for 1 hour for decolorization, the pump is transferred to the filter press to filter out the activated carbon, and the liquid enters the evaporation and concentration kettle. When heated and evaporated under normal pressure to a normal pressure of 120-125 °C, it enters the slicer to cool and slice to obtain the product sodium p-toluenesulfonate. , and the evaporated water vapor is condensed and recycled to prepare water for alkali neutralizing agent. After sampling and analysis, the content of sodium p-toluenesulfonate is 89.4%, which can reach the refined grade standard and meet the market quality requirements.