Abstract: Isocyanates are produced in the gas phase and by-products such as ammonium halides are selectively separated from the gas phase by desublimation.

Abstract: Isocyanates are produced in the gas phase and by-products such as ammonium halides are selectively separated from the gas phase by desublimation.

Abstract: A process for the preparation of an aromatic carbonate is disclosed. The process entails reacting an aromatic hydroxy compound of the formula R—(O—H)k, with carbon monoxide and oxygen, optionally in a solvent and in the presence of catalyst components, characterized in that after an initial partial charge of R—(O—H)k to the reaction mixture, the balance thereof is subsequently metered into the reaction mixture at least once in the course of the reaction.

Abstract: The preparation of quaternary salt phenolate solutions is disclosed. The preparation entails mixing an aqueous hydroxide-containing solution with an organic phase that contains phenol and quaternary salt, distilling off the water and precipitating and filtering off the resulting salt.

Abstract: The invention relates to a process for the removal of deposits formed in a reaction apparatus by the precipitation of solids from a liquid reaction mixture, which process is characterized in that particles of a material that is inert under the reaction conditions are introduced into the reaction apparatus, which particles, by suitable mechanical circulation of the reaction mixture, are so moved through the reactor that, during the reaction, by striking the walls or other built-in elements, they abrasively remove precipitates adhered thereto.

Abstract: A process for the separation a substantially adduct-free diaryl carbonate from reaction solution is disclosed. The process entails obtaining a solution that contains diaryl carbonate, catalyst system components and an aromatic solvent, lowering the temperature of the solution, optionally in the presence of a nucleating agent, to produce a crystallization product, and washing the crystallization product with an anhydrous wash solution to remove catalyst residues and impurities.

Abstract: A process for producing diaryl carbonate is disclosed. The process entails forming a reaction mixture wherein reacting are an aromatic hydroxy compound corresponding to the formula R—O—H??(II), wherein R denotes a C6-22-aromatic hydrocarbon radical, with CO and O2 in the presence of a catalyst system. The catalyst system contains components a) a Group VIII B metal compound, b) at least one second metal compound, c) a bromide compound, and d) a base. The process entails introduction of one or more of components a) to d) to the reaction mixture in more than one increment in the course of the reaction.

Abstract: The invention relates to a process for the removal of deposits formed in a reaction apparatus by the precipitation of solids from a liquid reaction mixture, which process is characterized in that particles of a material that is inert under the reaction conditions are introduced into the reaction apparatus, which particles, by suitable mechanical circulation of the reaction mixture, are so moved through the reactor that, during the reaction, by striking the walls or other built-in elements, they abrasively remove precipitates adhered thereto.

Abstract: A process for the production of an aromatic carbonate is disclosed.

Abstract: A process for the separation a substantially adduct-free diaryl carbonate from reaction solution is disclosed. The process entails obtaining a solution that contains diaryl carbonate, catalyst system components and an aromatic solvent, lowering the temperature of the solution, optionally in the presence of a nucleating agent, to produce a crystallization product, and washing the crystallization product with an anhydrous wash solution to remove catalyst residues and impurities.

Abstract: A process for the removal and recovery of quaternary salt (A) and base (D) from a reaction mixture is disclosed. The reaction mixture resulting from oxidative direct carbonylation contains in addition to (A) and (D), at least one hydroxyaromatic compound (B) and at least one reaction product (C) and optionally a solvent, and the process entails a) adding acid to the reaction mixture to cause conversion of (D) into a hydroxyaromatic compound (B2) b) separating the reaction mixture into b1.) that contains (C) and optionally (B) and/or (B2) and b2.) that contains (A) and optionally (B) and/or (B2), and c) reacting b1.) with a base (E) to re-form (D).

Abstract: A process for the separation a substantially adduct-free diaryl carbonate from reaction solution is disclosed. The process entails obtaining a solution that contains diaryl carbonate, catalyst system components and an aromatic solvent, lowering the temperature of the solution, optionally in the presence of a nucleating agent, to produce a crystallization product, and washing the crystallization product with an anhydrous wash solution to remove catalyst residues and impurities.

Abstract: A process for the separation and recycling of catalyst components from a chemical reaction mixture is disclosed. The process entails at least one extraction step.

Abstract: A process for the preparation of a solution of a quaternary cation and an anion from a deprotonated hydroxy aromatic in an organic solvent by means of a reactive extraction of a quaternary salt in the presence of an aqueous hydroxide solution, a hydroxy aromatic and an organic solvent is disclosed. Also disclosed is a process for the recycling of a quaternary salt phenolate solution from a reaction mixture.

Abstract: A process for the separation and recycling of catalyst components from a chemical reaction mixture is disclosed. The process entails at least one extraction step.

Abstract: A process for the removal and recovery of quaternary salt (A) and base (D) from a reaction mixture is disclosed. The reaction mixture resulting from oxidative direct carbonylation contains in addition to (A) and (D), at least one hydroxyaromatic compound (B) and at least one reaction product (C) and optionally a solvent, and the process entails a) adding acid to the reaction mixture to cause conversion of (D) into a hydroxyaromatic compound (B2) b) separating the reaction mixture into b1.) that contains (C) and optionally (B) and/or (B2) and b2.) that contains (A) and optionally (B) and/or (B2), and c) reacting b1.) with a base (E) to re-form (D).

Abstract: A process for the preparation of a solution of a quaternary cation and an anion from a deprotonated hydroxy aromatic in an organic solvent by means of a reactive extraction of a quaternary salt in the presence of an aqueous hydroxide solution, a hydroxy aromatic and an organic solvent is disclosed. Also disclosed is a process for the recycling of a quaternary salt phenolate solution from a reaction mixture.

Abstract: The preparation of quaternary salt phenolate solutions is disclosed. The preparation entails mixing an aqueous hydroxide-containing solution with an organic phase that contains phenol and quaternary salt, distilling off the water and precipitating and filtering off the resulting salt.

Abstract: A process for the separation a substantially adduct-free diaryl carbonate from reaction solution is disclosed. The process entails obtaining a solution that contains diaryl carbonate, catalyst system components and an aromatic solvent, lowering the temperature of the solution, optionally in the presence of a nucleating agent, to produce a crystallization product, and washing the crystallization product with an anhydrous wash solution to remove catalyst residues and impurities.

Abstract: A process for the preparation of an aromatic carbonate is disclosed. The process entails reacting an aromatic hydroxy compound of the formula R—(O—H)k, with carbon monoxide and oxygen, optionally in a solvent and in the presence of catalyst components, characterized in that after an initial partial charge of R—(O—H)k to the reaction mixture, the balance thereof is subsequently metered into the reaction mixture at least once in the course of the reaction.