Abstract: The invention relates to a process for preparing concentrated solutions of polymerization inhibitor, that can be used for the production, purification and storage of monomer compositions. This process comprises a step in which at least one polymerization inhibitor in the molten state is mixed with a solvent.

Abstract: The invention relates to a process for preparing concentrated solutions of polymerization inhibitor, that can be used for the production, purification and storage of monomer compositions. This process comprises a step in which at least one polymerization inhibitor in the molten state is mixed with a solvent.

Abstract: A process for the manufacture of polyamide is described. Also described, is a process comprising a stage of initial polymerization under pressure starting from monomers and a stage of finishing in the liquid phase at atmospheric pressure. The finishing stage can employ an injection of inert gas along a direction essentially parallel to that of the flow of the liquid reaction stream.

Abstract: The present invention relates to a method for preparing cationic galactomannans, comprising the following steps: a) a step in which galactomannans are impregnated with an alkaline agent; b) a step in which the mixture formed in step a) is impregnated with a cationic agent; and c) a step in which the mixture is formed in step b) is dried.

Abstract: A method for manufacturing a solution of a diacid and diamine salt for manufacturing polyamide is described. A method for manufacturing an aqueous solution of diacid and diamine salts produced by mixing at least two diacids and at least one diamine, with a weight concentration of salt between 40% and 70%, including, in a first step, preparing an aqueous solution of diacid(s) and diamine(s) with a diacid/diamine mole ratio of less than 1 using one diacid and one diamine, and in a second step, adjusting the mole ratio of diacids/diamine(s) to a value of between 0.9 and 1.1, and fixing the weight concentration of salt by adding another diacid and, optionally, additional water and/or diamine is also described.

Abstract: The present invention relates to a method for continuously preparing a betaine aqueous solution, including the reaction of an amine with an ?-halocarboxylic acid, in the presence of water and a base. Said method is characterized in that it is carried out in a device consisting of at least two consecutive reactors (R1) and (R2), the reactor (R2) being a tubular reactor.

Abstract: Polyamides, e.g., polyhexamethylene adipamide, are continuously produced via the following stages: Stage 1: into and through a reactor, polycondensing a liquid stream which contain the polyamide monomer(s) at a pressure P1 greater than atmospheric pressure, the stream of material at the outlet of the reactor including a vapor phase which contains steam and a liquid phase which at least contains the product of polycondensation; Stage 2: feeding the outlet stream of material into a chamber, evacuating at least a portion of the vapor phase therefrom and recovering at least the liquid phase which at least contains the product of polycondensation, the pressure P2 in the chamber being regulated at a set value such that it is greater than atmospheric pressure and the residence time of said liquid phase in the chamber being less than 5 minutes; and Stage 3: pressure reducing at least the liquid phase which at least contains the stream of polycondensation product recovered during Stage 2.

Abstract: A process for the manufacture of polyamide is described. Also described, is a process comprising a stage of initial polymerization under pressure starting from monomers and a stage of finishing in the liquid phase at atmospheric pressure. The finishing stage can employ an injection of inert gas along a direction essentially parallel to that of the flow of the liquid reaction stream.

Abstract: The present invention relates to a method for continuously preparing a betaine aqueous solution, including the reaction of an amine with an ?-halocarboxylic acid, in the presence of water and a base. Said method is characterized in that it is carried out in a device consisting of at least two consecutive reactors (R1) and (R2), the reactor (R2) being a tubular reactor.

Abstract: A method for manufacturing a solution of a diacid and diamine salt for manufacturing polyamide is described. A method for manufacturing an aqueous solution of diacid and diamine salts produced by mixing at least two diacids and at least one diamine, with a weight concentration of salt between 40% and 70%, including, in a first step, preparing an aqueous solution of diacid(s) and diamine(s) with a diacid/diamine mole ratio of less than 1 using one diacid and one diamine, and in a second step, adjusting the mole ratio of diacids/diamine(s) to a value of between 0.9 and 1.1, and fixing the weight concentration of salt by adding another diacid and, optionally, additional water and/or diamine is also described.

Abstract: The invention relates to, and the general field of the invention is that of, the synthesis of silicone resins, more particularly the synthesis of silicone resins of type MQ. The process relates to the preparation of MQ silicone resins and permits better control of the operating conditions in the step of the polymerization of a sodium silicate (B) in aqueous medium in the presence of an acid (C) to form a silica hydrosol (polysilicic acid). In the course of the polycondensation step the reactants, a sodium silicate and an acid, are mixed, preferably in continuous fashion, dynamically to form a mixture (3), by means of at least one intensive mixing tool (M) producing a power ? per unit volume of more than 10 kW/m3.

Abstract: Polyamides, e.g., polyhexamethylene adipamide, are continuously produced via the following stages: Stage 1: into and through a reactor, polycondensing a liquid stream which contain the polyamide monomer(s) at a pressure P1 greater than atmospheric pressure, the stream of material at the outlet of the reactor including a vapor phase which contains steam and a liquid phase which at least contains the product of polycondensation; Stage 2: feeding the outlet stream of material into a chamber, evacuating at least a portion of the vapor phase therefrom and recovering at least the liquid phase which at least contains the product of polycondensation, the pressure P2 in the chamber being regulated at a set value such that it is greater than atmospheric pressure and the residence time of said liquid phase in the chamber being less than 5 minutes; and Stage 3: pressure reducing at least the liquid phase which at least contains the stream of polycondensation product recovered during Stage 2.

Abstract: The invention relates to, and the general field of the invention is that of, the synthesis of silicone resins, more particularly the synthesis of silicone resins of type MQ. The process relates to the preparation of MQ silicone resins and permits better control of the operating conditions in the step of the polymerization of a sodium silicate (B) in aqueous medium in the presence of an acid (C) to form a silica hydrosol (polysilicic acid). In the course of the polycondensation step the reactants, a sodium silicate and an acid, are mixed, preferably in continuous fashion, dynamically to form a mixture (3), by means of at least one intensive mixing tool (M) producing a power ? per unit volume of more than 10 kW/m3.