Patent application number | Description | Published |
20090088567 | PURIFICATION OF A CRUDE LACTAM MIXTURE BY MEANS OF MELT CRYSTALLIZATION - The present invention provides a method for purifying laurolactam from a crude lactam mixture. In the method of the present invention, laurolactam is selectively crystallized by melt crystallization with controlled cooling of the crude lactam mixture. | 04-02-2009 |
20110046297 | METHOD FOR PRODUCING AND PURIFYING AQUEOUS PHASES - The present invention relates to a method for purifying an unpurified phase, containing a target product, preferably (meth)acrylic acid, water, and at least one impurity differing from the target product and from water comprising: a) crystallizing the target product and waters; b) separating the crystals from the mother liquor created in step a); c) melting at least part of the separated crystals to form a melt; and d) recycling at least part of said melt to step b). The invention further relates to a method for the production of a purified phase, containing a target product and water, a method for the production of a polymer based on (meth)acrylic acid, polymers that may be obtained by means of said method, chemical products, such as fibers or molded bodies, and the use of polymers. | 02-24-2011 |
20110105791 | PROCESS FOR PREPARING ACRYLIC ACID PURIFIED BY CRYSTALLIZATION FROM HYDROXYPROPIONIC ACID AND APPARATUS THEREFORE - The invention relates to a process for the preparation of acrylic acid and a process for the preparation of polyacrylic acid comprising the process steps: (a1) preparation of 3-hydroxypropionic acid from a biological material to give a fluid, in particular aqueous, phase containing 3-hydroxypropionic acid; (a2) dehydration of the 3-hydroxypropionic acid to give a fluid, in particular aqueous, solution containing acrylic acid; (a3) purification of the solution containing acrylic acid by a suspension crystallization or a layer crystallization to give a purified phase; and corresponding devices for carrying out these processes, and acrylic acid and polyacrylates. The invention is distinguished in that acrylic acid and polyacrylates can thereby be prepared efficiently, inexpensively, and sustainably with simple means and with a high purity on the basis of regenerable raw materials. | 05-05-2011 |
20110124855 | METHOD FOR ISOLATION OF LAUROLACTAM FROM A LAUROLACTAM SYNTHESIS PROCESS STREAM - A process for purifying laurolactam by means of integrated connection of distillation and crystallization is provided. The crystallization is performed as a solution or melt crystallization. The process reduces thermal stress applied to the laurolactam stream and improved yields are obtained. Raw materials are recovered and recycled in the production sequence. | 05-26-2011 |
20120232233 | SUPERABSORBENT POLYMERS AND METHODS OF MAKING THE SAME - In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a | 09-13-2012 |
20130053522 | SUPERABSORBENT POLYMERS AND METHODS OF MAKING THE SAME - In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer. | 02-28-2013 |
20130253149 | SUPERABSORBENT POLYMERS AND METHODS OF MAKING THE SAME - In one aspect, a process for the preparation of a superabsorbent polymer is described herein. In some embodiments, the process comprises (I) preparing acrylic acid, wherein the process comprises (a1) provision of a fluid F1 having a composition comprising from about 5 to about 20 wt. % of hydroxypropionic acid, salts thereof, or mixtures thereof; from about 0.1 to about 5 wt. % of inorganic salts; from about 0.1 to about 30 wt. % of organic compounds which differ from hydroxypropionic acid; from 0 to about 50 wt. % of solids; and from about 20 to about 90 wt. % of water; (a2) dehydration of said hydroxypropionic acid to give a fluid F2 containing acrylic acid; and (a3) purification of said fluid F2 to give a purified acrylic acid phase comprising acrylic acid having a purity of at least 70 wt. %; and (II) polymerizing the acrylic acid of (I) to form a superabsorbent polymer. | 09-26-2013 |
20130253226 | PROCESS FOR PREPARING 3-AMINOMETHYL-3,5,5-TRIMETHYLCYCLOHEXYLAMINE - The invention relates to an improved process for preparing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, referred to hereinafter as isophoronediamine or, in abbreviated form, IPDA, by: I. preparation of isophorone by catalyzed aldol condensations with acetone as reactant; II. reaction of isophorone with HCN to form isophoronenitrile (IPN, 3-cyano-3,5,5-trimethylcyclohexanone); III. catalytic hydrogenation and/or catalytic reductive amination (also referred to as aminative hydrogenation) of 3-cyano-3,5,5-trimethylcyclohexanone, hereinafter called isophoronenitrile or, in abbreviated form, IPN, to give the isophoronediamine. | 09-26-2013 |
20130261343 | METHOD FOR PRODUCING ISOPHORONE - The invention relates to a method for producing isophorone by catalyzed aldol condensation of acetone as an educt, reprocessing the reaction product, hydrolyzing the product stream, and separating into an organic and an aqueous fraction, obtaining isophorone from the organic fraction, distillatively reprocessing the aqueous fraction, and feeding the vapors from the head of the distillative reprocessing apparatus into the hydrolysis apparatus. | 10-03-2013 |
20140187817 | PREPARATION OF METHACRYLIC ACID - The invention relates to a process for preparation of methacrylic acid, comprising process steps a) providing a crude methacrylic acid-comprising aqueous solution comprising at least one impurity at least partially dissolved therein; b) precipitation of at least a part of the at least one impurity from the crude methacrylic acid-comprising aqueous solution to form at least one solid impurity and a mother liquor; c) separation of at least a part of the at least one solid impurity from the mother liquor to obtain a purified methacrylic acid-comprising aqueous solution and a solid impurity; d) separation of methacrylic acid from the purified methacrylic acid-comprising aqueous solution. | 07-03-2014 |
20150045585 | HYDROLYSIS OF THE RESIDUES OBTAINED IN THE PRODUCTION OF ISOPHORONE TO RECOVER ISOPHORONE AND ACETONE - A process for preparing isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) is provided wherein distillation vapors from the work-up of product fractions are recycled to earlier stages of operation of the process. | 02-12-2015 |