摘要:
A process for precipitating cystine from a solution in sulfuric acid, includes forming a mixture of a solution of cystine in aqueous sulfuric acid and of an aqueous solution of a base by simultaneous metering the cystine solution and the aqueous base solution into a mixing container. The metering takes place in such a way that the mixture in the container has a pH between 1.0 and 7.0 and a temperature between 30° C. and the boiling point of the mixture.
摘要:
Process for the hydrolytic ring cleavage of thiazolidine derivatives to give 2-aminomercaptan derivatives and carbonyl compounds, which comprises bringing an aqueous solution of the thiazolidine derivative into contact with an acidic cation exchanger in the H+ form, giving a solution L1 which contains the carbonyl compound and eluting the cation exchanger with a suitable eluent, giving a solution L2 which contains the 2-aminomercaptan derivative.
摘要:
Glycosylation of 2,6-diaminopurines or silyl derivatives thereof with a compound of the structure is facilitated by the presence of an optionally silylated 1,3-dicarbonyl compound during glycosylation. Byproducts are minimized, while stereoselectivity may be altered by choice of Lewis acid and other reaction condictions.
摘要:
Optimization of an installation in which an operation is performed that requires control over the atmosphere inside a chamber (3), the operation being performed in the presence of a gaseous mixture capable of giving off emissions, the optimization being obtained by the presence of inlet (5) and outlet (8) devices external to the chamber to oppose the ingress of air into the chamber and the exit of gaseous emissions; and of an extraction device (4) comprising means (42) for regulating the flow rate to maintain an approximately zero pressure differential between the inside and the outside of the chamber.