摘要:
The present invention relates to a process for preparing polyoxyalkylene glycol of high purity and having a low color number from the corresponding alkylene glycol and a starter in the presence of a basic catalyst, wherein a reducing agent is present in the polymerization.
摘要:
A process is described for purifying polyalkylene glycols obtained by adding alkylene oxide to alkylene glycol, in which, after addition is complete, the resultant polyalkylene glycol is treated at a pH of >7 with a bleaching agent selected from the group consisting of peroxides, peracids, percarbonates, perborates, peroxodisulfates or oxygen, in each case with or without addition of a bleaching activator. The process is suitable in particular for preparing polyethylene glycol having molar weights from 196 to 203 g/mol which meets requirements of pharmacopeias.
摘要:
A process is described for purifying polyalkylene glycols obtained by adding alkylene oxide to alkylene glycol, in which, after addition is complete, the resultant polyalkylene glycol is treated at a pH of >7 with a bleaching agent selected from the group consisting of peroxides, peracids, percarbonates, perborates, peroxodisulfates or oxygen, in each case with or without addition of a bleaching activator.The process is suitable in particular for preparing polyethylene glycol having molar weights from 196 to 203 g/mol which meets requirements of pharmacopeias.
摘要:
A method for handling aqueous solutions of methanesulfonic acid (MSA) having a concentration from 50 to 99% by weight of MSA and a total chlorine content of less than 50 mg/kg in apparatuses in which the aqueous MSA solution is in contact with steel surfaces. The steel comprises austenitic steels having a chromium content of from 15 to 22% by weight and a nickel content of from 9 to 15% by weight.
摘要:
The invention relates to novel compounds which bind to integrin receptors, their use as ligands of integrin receptors, in particular as ligands of the αvβ3 integrin receptor, their use, and pharmaceutical preparations comprising these compounds.
摘要:
A process is proposed for the preparation of a crystalline L-MGDA trialkali metal salt by crystallization from an aqueous solution thereof which has been obtained by Strecker synthesis, starting from L-α-alanine, by reaction with formaldehyde and hydrocyanic acid to give L-α-alanine-N,N-diacetonitrile and subsequent alkaline saponification of the L-α-alanine-N,N-diacetonitrile to give the L-MGDA trialkali metal salt, wherein a temperature of 150° C. is not exceeded during the alkaline saponification.
摘要:
A process is proposed for the preparation of a crystalline L-MGDA trialkali metal salt by crystallization from an aqueous solution thereof which has been obtained by Strecker synthesis, starting from L-α-alanine, by reaction with formaldehyde and hydrocyanic acid to give L-α-alanine-N,N-diacetonitrile and subsequent alkaline saponification of the L-α-alanine-N,N-diacetonitrile to give the L-MGDA trialkali metal salt, wherein a temperature of 150° C. is not exceeded during the alkaline saponification.
摘要:
Process for preparing hydrocyanic acid by catalytic dehydration of gaseous formamide, in which a formamide-containing recycle stream is obtained from the product mixture after the dehydration and is recirculated to the dehydration, wherein the formamide-containing recycle stream contains from 5 to 50% by weight of water.
摘要:
A process for preparing an aqueous solution of a methylglycine-N,N-diacetic acid trialkali metal salt at a high yield and purity by Strecker synthesis, the process including: reacting an aqueous solution containing α-alanine with formaldehyde and hydrocyanic acid, to obtain α-alanine-N,N-diacetonitrile in one reaction unit; and saponification of the α-alanine-N,N-diacetonitrile with a base, to obtain the methylglycine-N,N-diacetic acid trialkali metal salt, wherein the α-alanine is partially neutralized and the addition of formaldehyde and hydrocyanic acid are controlled such that a concentration of free hydrocyanic acid in the liquid reaction mixture at any time is limited such that secondary reactions that produce formaldehyde cyanohydrin, consecutive reactions of formaldehyde cyanohydrin, and the polymerization of hydrocyanic acid, only occur insofar as the specification requirements, such as nitrilotriacetic acid content and color, for methylglycine-N,N-diacetic acid trialkali metal salts are observed.