摘要:
Disclosed is the synthesis of terminal diols, which are organic intermediates used in order to produce polymeric materials, by starting from terminal diolefins, which synthesis is based on the oxidation of diolefins to yield diepoxides, in a double-phase aqueous-organic system with hydrogen peroxide and in the presence of catalysts soluble in the organic phase, followed by a reaction of reduction of the resulting diepoxides.
摘要:
The invention relates to a significantly improved process for the preparation of benzothiadxazole compounds which can be used in the production of Luminescent Solar Concentrators, (LSC). In particular, the synthesis process of the present invention is oriented towards the preparation of 4,-di-2-thienyl-2,1,3-benzo-thiadiazole.
摘要:
Process for the preparation of stable nitroxyl radicals (I) starting from N-benzylphthalimide in two steps. In the first step, the intermediate N-benzyl-1,1,3,3-tetra-alkylisoindoline is prepared by treatment with a Grignard reagent, prepared in methyl-tert-butyl ether, of N-benzylphthalimide, obtained in the same reaction environment starting from phthalic anhydride and benzylamine. In the second step, the N-benzyl-1,1,3,3-tetra-alkylisoindoline is transformed into the nitroxyl radical by hydrogenolysis and subsequent oxidation with hydrogen peroxide in the presence of a catalyst selected from acids and salts of polymolybdic or polytungstic acids.
摘要:
Integrated process for the preparation of aromatic isocyanates comprising: the reaction between an aromatic amine and an organiccarbonate in the presence of a catalyst selected from organic and inorganic salts of a metal selected from Zn, Sn, Pb, Cu; the removal of the catalyst; the passivation of the quantity of residual metal in the urethane formed in step a); the removal of the organic solvent and its optional recycling to step a) of the reaction; the evaporation of the aromatic urethane with partial pyrolysis; the complete pyrolysis of the urethane in gas phase; the recovery of the isocyanate.
摘要:
Disclosed is a process for separating metal catalysts based on ammonium and phosphonium phosphotungstates from reaction mixtures in which they are dissolved. The process is based on the use of semipermeable membranes and has found an useful application in the separation of the above said catalysts from mixtures obtained from alkenes and soybean oil epoxidation.
摘要:
Process for the preparation of stable nitroxide radicals (I) starting from N-benzylphthalimide in three steps. In the first step, the N-benzylphthalimide is transformed into N-benzyl-1,1,3,3-tetralkylisoindoline by treatment with a Grignard reagent prepared in methyl-tert-butyl ether. In the second step, the N-benzyl-1,1,3,3-tetraalkylisoindoline is transformed into 1,1,3,3-tetra-alkylisoindoline by hydrogenolysis. In the third step, the 1,1,3,3-tetra-alkyl-isoindoline is transformed into the nitroxide radical by oxidation with hydrogen peroxide in the presence of a catalyst selected from acids and salts of polymolybdic or polytungstic acids.
摘要:
A biotechnological process for preparing L(-)-carnitine chloride, having the formula ##STR1## comprising: (a) reacting a racemic ester of (R,S)-3,4-epoxybutyric acid having the formula ##STR2## wherein R is an alkyl group having from 1 to 10 carbons or a benzyl group, with an enzyme capable of selectively hydrolyzing enantiomer S(-);(b) separating the enantiomer S(-) from non-reacted ester which is present in predominantly the R(+) form;(c) reacting the non-reacted ester obtained in step (b) with an enzyme capable of quantitatively hydrolyzing the R(+) form to obtain thereby a salt of 3,4-epoxybutyric acid in the R(+) form having the formula ##STR3## wherein X is Na, K, or Li; (d) reacting the salt obtained in step (c) with a molar excess of trimethylamine; and(e) treating the reaction product of step (d) with HCl to remove excess trimethylamine and to obtain thereby the L(-)-carnitine chloride of formula (I).
摘要:
A process for preparing L(-)-carnitine chloride having the formula: ##STR1## comprising the steps of: (a) reacting a racemic ester of (R,S)-3,4-epoxybutyric acid having the formula: ##STR2## wherein R is an alkyl group having from 1-10 carbons, or a benzyl group, with an enzyme capable of selectively hydrolyzing enantiomer S(-),(b) separating said enantiomer S(-), from non-reacted ester, which is predominantly in the R(+) form;(c) reacting (1) the non-reacted ester obtained in step (b) with trimethylamine hydrochlorid or (2) the trimethylamine, to obtain thereby an ester having the formula: ##STR3## (d) hydrolyzing the ester obtain in step (c) in the presence of HCl to obtain thereby the L(-)-carnitine chloride having formula (I).The present invention is also directed to a novel class of compounds comprising R(+) enantiomers of the esters of 3,4-epoxybutyric acid.