Vysoka Skola Chemicko-technologicka

Ceskoslovenska Akademie Ved

Vysoka, Skola Chemiko-technologicka

Jaroslav Kralicek

Vladimir Kubanek

Jaroslava Kondelikova

Jiri Machacek

Bohuslav Casensky

Zdenek Jerman

Stanislav Najmr

Zdenek Fencl

Josef Skach

Gabriela Basarova

Jiri Marik

Jan Roda

Jiri Budin

Eduard Sittler

Zdenek Sterbacek

The invention pertains to a method for postpolymerization of granules of polyamide based on .epsilon.-caprolactam and formed by the anionic polymerization in melt and solves the problem of decreasing the content of low-molecular-weight substances in granules. At the same time, the invention pertains to an arrangement of equipment for performing the postpolymerization. The objective of the invention is a method for the continuous postpolymerization of polyamide based on .epsilon.-caprolactam and formed by the anionic polymerization in melt, wherein the postpolymerization proceeds in two stages, while the granules are heated in the first stage to the required temperature of postpolymerization 160.degree. to 200.degree. C. for 5 to 30 minutes during their vertical transport and allowed at this temperature for 2 to 6 hours in the second stage without mechanical intervention at their gravitation transport which is assisted by vibrations or a reservoir. An equipment for performing the method according to the invention which is formed by a two-stage unit consisting of a vertical vibration conveyer-heat exchanger and a reservoir, while the heat exchanger is provided with a heating jacket, a hopper in the lower part, and a heated overfall in the upper part, through which it is connected with the reservoir, while the reservoir is furnished outside with a jacket and a vibrator, inside with two plate heat-exchangers with the heating controlled by a temperature sensor, and in the lower part with a turnstile.

Method for postpolymerization of polyamide granules after polymerization

A process for producing a pure magnesium sulphite from crude crystalline magnesium sulphite. Into a full suspension or flow containing magnesium sulphite crystals at least one further water-containing and heat-supplying flow is led. The heat-supplying flow rapidly increases the temperature of the suspension to above 80.degree. C. in less than 10 seconds, preferably in less than 2 seconds. The solid water-insoluble fraction is then separated from the resulting flow, and the pure product is recrystallized from the solution. The solution may be recycled into the process either for further purification or for use as at least one heat-supplying flow.

Process for producing pure magnesium sulphite

Process of purification of magnesic raw material. Sulphur dioxide is allowed to react with an aqueous suspension of calcinated magnesite, crude or contaminated magnesium oxide, magnesium hydroxide, hydrated magnesium carbonates, or crude crystals of magnesium sulphite, and, after reaching a pH of 3 to 7.5 the reaction mixture is separated into a solid phase at least one fraction of which is rich in MgSO.sub.3.xH.sub.2 O, wherein x stands for 3 or 6, and at least one fraction containing concentrated impurities. The whole process is carried out at least once. A reaction mixture having a pH below 5 can be preferably transferred to pH 5.2 by the addition of an alkali, e.g. magnesium oxide or magnesium hydroxide, whereupon separation of at least two fractions of the solid phase is accomplished. The fractions obtained can be further purified by mixing in a hydrophilic liquid, and by a following separation. The fraction of crude magnesium sulphite crystals can be heated to a temperature over 60 degress C., preferably to 90 to 100 degrees C., whereupon the solution containing magnesium sulphite is separated from solid impurities, or the treated mixture is cooled to a temperature below 60 degrees C. and solid phases are separated into one or more fractions rich in MgSO.sub.3.xH.sub.2 O and to one or more fractions mainly containing impurities. Filtration, sedimentation, or centrifugation can be used for the separation.

Process of purification of magnesic raw material

Process which accelerates the activated and non-activated polymerization of 2-pyrrolidone. A prepared polymerization charge containing monomer and components of the initiation system is first allowed to polymerize at a temperature above the monomer melting temperature, then is cooled below the melting point of the mixture, and then the crystalline reaction mixture is heated to a polymerization temperature of 25.degree. to 60.degree. C.

Process for the anionic polymerization of 2-pyrrolidone with fast

A method is described for the anionic polymerization and copolymerization of .omega.-aminoacid lactams. This end is attained at elevated temperatures in the presence of a polymerization initiator of the formula

Method of anionic polymerization of .omega.-aminoacid lactams with

A method for treating beverages containing turbidity procursors and/or enzymes is described. The technique involves contacting the beverages with a diol or dicarboxylic acid polycondensate at a temperature ranging from 28.4.degree. to 176.degree. F., thereby resulting in separation of deleterious substance. The colloidal and taste qualities of the resultant beverages is thereby enhanced.

Method for stabilizing colloidal and taste qualities of beverages

A method for the anionic polymerization of unsaturated monomers involves effecting reaction in the presence of an organic derivative of a metal alumina hydride in an amount ranging from 0.01 to 5.0 mol percent based upon the amount of unsaturated monomer.

Growing community of inventors

Prague, Czechia

Jaroslav Kralicek