Water → Calcium DL-tartrate

Participants

Reaction Conditions

Reaction Steps

D,L-tartaric acid, 44.7 g, 101.05 g of 50% sodium hydroxide, 50 g water, and 1.5 g calcium hydroxide were placed in a 500 ml round bottom flask fitted with a thermometer, condenser, addition funnel and mechanical stirrer. A calcium tartrate filter cake from a previous reaction (133.2 g,50% solids) was added to the reactor. The mixture was stirred at 120 rpm and heated to 80°±2° C. The calcium maleate solution was added and the reaction continued at 88°±2° C. Water, 73 g, was stripped from the reaction mixture with a flowing air stream over the 40 minutes of reaction. The reaction solution clarified after about one hour. Total reaction time was three hours. 250 g of water was added and the mixture cooled slowly while slowly adding acetic acid, 13.8 g over30 minutes. At the end of this time the pH of the mixture had been reduced to 9.13 and the temperature reached 68° C. Then the mixture was slowly cooled over 75 minutes from 68° C. to 35° C. Finally,the mixture was cooled to 27° C. in an ice bath. The mixture was filtered using a fritted glass filter funnel. The filtration took only five minutes and provided 485.5 g of filtrate and 59.1 g of calcium tartrate wet cake. On standing overnight, additional calcium tartrate crystallized out and was filtered off, weight, 17.6 g.

Provenance & Evidence