How to prepare calciumthioglycolte from 80% thioglycolic acid, we are preparing aqueous media its coming clear solution please give any suggustion. which solvent is suitable for this reaction.
Dear
Vasu Vasanth
Thioglycolic acid is a colorless liquid with an unpleasant odor. Density 1.325 g / cm3. Used to make permanent wave solutions and depilatories. Corrosive to metals and tissue.
Industrially, mercaptoacetic acid is produced from chloroacetic acid or its salts and sodium or potassium hydrogen sulfide. Thiodiglycolic acid, dithiodiglycolic acid, and glycolic acid may be formed as side products. The mercaptoacetic acid is isolated from the acidified reaction mixture by extraction with organic solvents (ethers, alcohols, or chlorinated hydrocarbons) and purified by distillation. Both batch and continuous processes have been described in the patent literature as well as processes that operate under a partial pressure of hydrogen sulfide or carbon dioxide.
In widely avail commercial cold-wave prepn for waving hair there is as a rule no free thioglycolic acid. Instead these prepn contain ammonium, sodium, or calcium thioglycolate at mildly alkaline pH, commonly pH 9.5 & are far less dangerous to the eye than is free thioglycolic acid.
Good luck
I would suggest reaction of an aqueous solution of thioglycolic acid with Ca(OH)2, which is slightly soluble in water. The only byproduct will be water, as the hydroxide ions are protonated.
Alternatively, calcium oxide and calcium carbonate could be used, but I think both are less desireable than calcium hydroxide. Calcium oxide will react exothermically with water to form the hydroxide, and the carbonate will produce carbon dioxide as a byproduct in addition to water--vigorous bubbling is likely undesirable given the stench of thioglycolic acid...
More soluble calcium salts like calcium chloride are also an option, but the extra ions might complicate isolation and purification of the desired product.
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