摘要:
A process for synthesizing aromatic urethanes, which entails:a) reacting an organic carbonate, in an amount which is equal to or greater than a stoichiometric amount, with an aromatic amine at a temperature of00 to 190.degree. C.; andb) recovering the aromatic urethane from the reaction mixture, wherein step a) is carried out by maintaining reaction alcohol in an amount of from 10 to 40 mol % based on a total quantity of alcohol coproduced during the reaction.
摘要:
A process is described for the preparation of aromatic urethanes in which organic carbonate in a stoichiometric quantity or in a quantity higher than the stoichiometric value is reacted with an aromatic amine operating in the presence of a carbamation catalyst, wherein this catalyst is selected from zinc and/or copper carbonate hydroxide. The process gives high yields and selectivity in the useful reaction product.
摘要:
A process is described for the preparation of aromatic carbamates in which an organic carbonate in a stoichiometric quantity or in a quantity higher than the stoichiometric value is reacted with an aromatic amine operating in the presence of a carbamation catalyst, wherein this catalyst is selected from N,N-substituted carbamate complexes of zinc or copper. The process gives high yields and selectivity in the useful reaction product.
摘要:
The present invention relates to a process for producing large amounts of 7.beta.-(4-carboxybutanamido)-cephalosporanic acid acylase ("GA") enzyme, which process consists in growing, under suitable culture conditions, a recombinant Escherichia coli K12 strain and subsequently extracting the enzyme from the resulting culture.Enzyme production is controlled by a particular expression system which can be induced by corn-steep liquor, an extremely low cost component of the culture medium.The enzyme can be used in the enzymatic preparation of 7-amino-cephalosporanic acid by starting from 7.beta.-(4-carboxybutanamido)-cephalosporanic acid.
摘要:
The optical isomers of racemic 1,2-diols are separated by enzymatic way, byeans of a process involving the following operations:reaction of the racemic mixture of the 1,2 diols with an organic anhydride in the presence of enzyme belonging to the class of lipases;separation of the enzyme;removal of the excess of anhydride;separation of the produced esters, in optically pure form by column chromatography;recovery of the 1,2 diols, as optically pure enantiomers.
摘要:
A process is described for separating the optical isomers of 1,2-isopropylideneglycerol, of formula (I), comprising partially stereoselective enzymatic hydrolysis of 1,2-isopropylideneglycerol benzoyl ester (II) catalyzed by a free or immobilized lipase, the hydrolysis being conducted in the presence of a cosolvent and followed by crystallization enabling crystals of (II) in raceme form and mother liquor containing (II) in the form of the pure enantiomer to be selectively obtained.The compound (I) is widely used industrially as an intermediate in the synthesis of chiral drugs such as (R)-(-)-carnitine, (S)-beta-blockers, (S)-antiviral agents, analgesic drugs etc.
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:
The present invention relates to a process for producing large amounts of 7.beta.-(4-carboxybutanamido)-cephalosporanic acid acylase ("GA") enzyme, which process consists in growing, under suitable culture conditions, a recombinant Escherichia coli K12 strain and subsequently extracting the enzyme from the resulting culture. Enzyme production is controlled by a particular expression system which can be induced by corn-steep liquor, an extremely low cost component of the culture medium. The enzyme can be used in the enzymatic preparation of 7-amino-cephalosporanic acid by starting from 7.beta.-(4-carboxybutanamido)-cephalosporanic acid.
摘要:
A process for the production of bio-oil from solid urban waste, comprising the following steps: a) subjecting said solid urban waste to liquefaction, obtaining a mixture including an oily phase consisting of bio-oil, a solid phase and an aqueous phase; b) subjecting the aqueous phase obtained in the liquefaction step a) to fermentation, obtaining a fermented biomass; c) feeding the fermented biomass obtained in the fermentation step b) to the liquefaction step a). The bio-oil (or bio-crude) thus obtained can be advantageously used in the production of biofuels which can be used as such or mixed with other motor vehicle fuels. Alternatively, this bio-oil (or bio-crude) can be used as such (biocombustible) or mixed with fossil combustibles (combustible oil, coal, etc.) for the generation of electric energy or heat.
摘要:
A heterogeneous catalyst is described, active in the metathesis reaction of olefins comprising alumina as inert carrier and a rhenium compound as active component, characterized in that rhenium is present in an amount of less than 5% by weight with respect to the total preferably from 1 to 4% by weight, and the inert carrier is impregnated with at least one inorganic halide selected from FeCl3, CuCl2, TiCl4, RuCl3, ZnCl2 and NH4Cl, and/or the corresponding bromides or iodides and, subsequently, treated at a high temperature.