The invention relates to the production of (meth)acrylic esters according to a continuous process by transesterification, and in particular to the purification of a crude reaction mixture comprising a C.sub.4-C.sub.12 (meth)acrylic ester using a divided wall column employed in a particular configuration. This configuration results in a simplification of the purification process with a reduced energy consumption and a minimized content of impurities present in the purified (meth)acrylic ester. The invention also relates to a process for the production of C.sub.4-C.sub.12 (meth)acrylic ester comprising this recovery/purification process.

The invention relates to the field of pharmaceutical synthesis, in particular to the preparation method of hexahydrofuro-furanol derivative, intermediates thereof and preparation methods thereof. The preparation methods comprises the steps of halogenation reaction, acylation reaction, enzymatic reduction reaction, reaction with amine compounds, reduction ring closure reaction (A1, A2, B, Cp1, C.sub.L, Cf)

##STR00001##

wherein, R.sub.1, R.sub.2, R.sub.3 are hydrogen or hydroxy protecting groups; R.sub.4 and R.sub.5 are the same or different and are phenyl, alkyl or substituted phenyl. In the preparation process of hexahydrofuro-furanol derivatives, the chirality is constructed by enzymatic method, and the product can be prepared with very high optical purity by adopting such technical means. The preparation method can be used to prepare the key intermediate, (3R, 3aS, 6aR)-hexahydrofuro[2,3-b]-3-ol, of Darunavir, in commercial production, which is a very economical route suitable for industrial production.

A cationic surfactant and a method of making the cationic surfactant are described. The method comprises reacting a lipophilic bio-based material having at least one epoxy functional group and a hydrophilic organic compound having at least one cationic functional group and at least one hydroxyl functional group to form a reaction product containing a stable ether linkage connecting the lipophilic bio-based material to the organic compound. At least a portion of the cationic functional groups is neutralized or ion exchanged with an organic acid. Incorporation of the simple organic acid reduces the surfactant's aquatic toxicity and acts as a substrate to encourage co-digestion of the surfactant molecule, making the compound more biodegradable.

A cationic surfactant and a method of making the cationic surfactant are described. The method comprises reacting a lipophilic bio-based material having at least one epoxy functional group and a hydrophilic organic compound having at least one cationic functional group and at least one hydroxyl functional group to form a reaction product containing a stable ether linkage connecting the lipophilic bio-based material to the organic compound. At least a portion of the cationic functional groups is neutralized or ion exchanged with an organic acid. Incorporation of the simple organic acid reduces the surfactant's aquatic toxicity and acts as a substrate to encourage co-digestion of the surfactant molecule, making the compound more biodegradable.

A cationic surfactant and a method of making the cationic surfactant are described. The method comprises reacting a lipophilic bio-based material having at least one epoxy functional group and a hydrophilic organic compound having at least one cationic functional group and at least one hydroxyl functional group to form a reaction product containing a stable ether linkage connecting the lipophilic bio-based material to the organic compound. At least a portion of the cationic functional groups is neutralized or ion exchanged with an organic acid. Incorporation of the simple organic acid reduces the surfactant's aquatic toxicity and acts as a substrate to encourage co-digestion of the surfactant molecule, making the compound more biodegradable.

Process for the production of 2-dimethylaminoethyl (meth)acrylate in multiple stage batch reactions involving the recycling of the catalyst (DBTO) in subsequent reaction, the addition a certain amount of fresh catalyst to the recycled catalyst, the use of said catalysts in the subsequent reaction, and wherein the volume decrease due to azeotropic distillation is compensate in order to keep the volume constant in the reactor during the reaction by the continuous addition of a composition comprising methyl(meth)acrylate and dimethylaminoethanol.

Process for the production of 2-dimethylaminoethyl (meth)acrylate in multiple stage batch reactions involving the recycling of the catalyst (DBTO) in subsequent reaction, the addition a certain amount of fresh catalyst to the recycled catalyst, the use of said catalysts in the subsequent reaction, and wherein the volume decrease due to azeotropic distillation is compensate in order to keep the volume constant in the reactor during the reaction by the continuous addition of a composition comprising methyl(meth)acrylate and dimethylaminoethanol.

The present invention is directed to a method of producing active pharmaceutical ingredients (APIs). The method includes subjecting a reaction mixture with an API precursor to solvent extraction to produce a reactant stream with the API precursor. The method includes concentrating the API precursor in the reactant stream using at least one membrane. The method includes carrying out a reaction in a membrane reactor. The method includes separating the API precursor from the reaction stream using a separator. The method includes crystallizing the API precursor using a crystallizer to produce APIs.

The present invention is directed to a method of producing active pharmaceutical ingredients (APIs). The method includes subjecting a reaction mixture with an API precursor to solvent extraction to produce a reactant stream with the API precursor. The method includes concentrating the API precursor in the reactant stream using at least one membrane. The method includes carrying out a reaction in a membrane reactor. The method includes separating the API precursor from the reaction stream using a separator. The method includes crystallizing the API precursor using a crystallizer to produce APIs.

The present invention is directed to a method of producing active pharmaceutical ingredients (APIs). The method includes subjecting a reaction mixture with an API precursor to solvent extraction to produce a reactant stream with the API precursor. The method includes concentrating the API precursor in the reactant stream using at least one membrane. The method includes carrying out a reaction in a membrane reactor. The method includes separating the API precursor from the reaction stream using a separator. The method includes crystallizing the API precursor using a crystallizer to produce APIs.