Abstract: The invention relates to a method for converting silicon tetrachloride by means of hydrogen to form trichlorosilane in a modified hydrodechlorination reactor. The invention further relates to a the use of such a modified hydrodechlorination reactor as an integrated component of a system for producing trichlorosilane from metallurgical silicon.

Abstract: The invention relates to an improved method for converting silicon tetrachloride having hydrogen in a hydrodechlorination reactor comprising a catalyst. The invention further relates to a catalytic system for such a hydrodechlorination reactor.

Abstract: 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.

Abstract: The invention relates to the use of a ceramic heat exchanger as an integral part of a process for catalytic dehalogenation of silicon tetrachloride to trichlorosilane in the presence of hydrogen, wherein the product gas and the reactant gases are conducted as pressurized streams through the heat exchanger, and the heat exchanger comprises heat exchanger elements made from ceramic material.

Abstract: The present invention relates to a multistage process for preparing trichlorosilane and silicon tetrachloride from metallurgical silicon, in which trichlorosilane and silicon tetrachloride are prepared from metallurgical silicon in a first step, and the silicon tetrachloride is processed further to the trichlorosilane end product in a second step. The present invention further relates to a plant in which such processes can be performed in an integrated manner.

Abstract: The invention relates to a method for converting silicon tetrachloride having hydrogen to trichlorosilane in a hydrodechlorination reactor, wherein the hydrodechlorination reactor is operated under pressure and comprises one or more reactor tubes which are made of a ceramic material. The invention further relates to the use of such a hydrodechlorination reactor as an integral component of a system for producing trichlorosilane from metallurgical silicon.

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to a method for producing higher hydridosilane wherein at least one lower hydridosilane and at least one heterogeneous catalyst are brought to reaction, wherein the at least one catalyst comprises Cu, Ni, Cr and/or Co applied to a carrier and/or oxide of Cu, Ni, Cr and/or Co applied to a carrier, the hydridosilane that can be produced according to said method and use thereof.

Abstract: 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.

Abstract: The present invention relates to superabsorbent polymer comprising acrylic acid made by the process comprising the steps of heating an aqueous glycerine solution to form glycerine; transporting the glycerine to the dehydration reactor; dehydrating the glycerine to an acrolein-comprising dehydration product; gas phase oxidating of the acrolein-comprising dehydration product to obtain an acrylic acid-comprising monomer gas; bringing into contact of the monomer gas with a quench agent to obtain an acrylic acid-comprising quench phase; working-up the quench phase to obtain an acrylic acid-comprising monomer phase; and polymerizing the acrylic acid-comprising monomer phase; wherein a plurality of gas bubbles is generated and wherein the dehydration occurs at least partially in the liquid phase. The superabsorbent polymer has certain properties for biodegradability and sustainability. Further, at least about 25% of the acrylic acid is based on glycerine.

Abstract: 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.

Abstract: The invention relates to a method for producing acrolein, comprising the following steps: (a) dehydrating an aqueous glycerin phase G1 in an acrolein reaction region, obtaining an aqueous acrolein reaction phase; (b) at least partially separating the aqueous acrolein reaction phase into an acrolein-rich acrolein phase and an acrolein-poor (in comparison to the acrolein phase) residual phase R1, wherein the residual phase R1 comprises glycerin, water and various remainders from glycerin and water; (c) recycling at least a part of the residual phase R2 in step (a); wherein i) from a glycerin phase G2 comprising remainders that differ from glycerin and water, at least one of said remainders is separated and the thus obtained, purified glycerin phase G2 is immediately supplied to the acrolein reaction region, or ii) at least one remainder different from glycerin and water is separated out of a mixture phase M1 obtained by mixing a glycerin phase G2 with the acrolein-poor residual phase R1, and the thus obtained,

Abstract: The present invention relates to a process for purifying low molecular weight hydridosilane solutions, in which a solution to be purified comprising a) at least one low molecular weight hydridosilane, b) at least one solvent and c) at least one impurity selected from the group of the compounds having at least 20 silicon atoms and/or the group of the homogeneous catalyst systems is subjected to a crossflow membrane process with at least one membrane separation step using a permeation membrane.

Abstract: The invention relates to a complete method for producing pure silicon that is suitable for use as solar-grade silicon, comprising the reduction of a silicon oxide, purified by acidic precipitation from an aqueous solution of a silicon oxide dissolved in an aqueous phase, using one or more pure carbon sources, the purified silicon oxide being obtained, in particular, by the precipitation of a silicon oxide dissolved in an aqueous phase in an acidifier. The invention also relates to a formulation containing an activator and to a device for producing silicon, a reactor and electrodes.

Abstract: The invention relates to a complete method for producing pure silicon that is suitable for use as solar-grade silicon, comprising the reduction of a purified silicon oxide using one or more pure carbon sources, the purified silicon oxide, which was purified as silicon oxide dissolved in an aqueous phase, having a content of other polyvalent metals or metal oxides, in relation to the silicon oxide, of less than or equal to 300 ppm, preferably less than 100 ppm, especially preferably less than 50 ppm and according to the invention less than 10 ppm of the other metals and being obtained advantageously by gel formation in alkaline conditions. The invention also relates to a formulation containing an activator and to the use of purified silicon oxide together with an activator for producing silicon.

Abstract: Process for preparing higher hydridosilanes of the general formula H—(SiH2)n—H where n?2, in which—one or more lower hydridosilanes—hydrogen, and—one or more transition metal compounds comprising elements of transition group VIII of the Periodic Table and the lanthanides are reacted at a pressure of more than 5 bar absolute, subsequently depressurized and the higher hydridosilanes are separated off from the reaction mixture obtained.

Abstract: The present invention relates to methods for the technical pyrolysis of a carbohydrate or carbohydrate mixture at an elevated temperature while adding silicon oxide, to a pyrolysis product obtainable in this way, and to the use thereof as a reducing agent for the production of solar silicon from silicic acid and carbon at a high temperature.

Abstract: An aqueous hydrogen peroxide solution containing i) less than 50 wppm alkali metals, alkaline earth metals or combinations thereof in total, irrespective whether the alkali or alkaline earth metals are present in cationic or complex form; ii) less than 50 wppm of amines having a pkB of less than 4.5 or the corresponding protonated compounds in total; and iii) at least 100 wppm anions or compounds that can dissociate to form anions in total, where the wppm are based on the weight of hydrogen peroxide and the concentration of hydrogen peroxide is more than 50% by weight based on the total weight of the hydrogen peroxide solution. A process for preparation of said hydrogen peroxide solution and the use of said solution in a process for epoxidation of olefins is also disclosed.

Abstract: The present invention relates to a process for production of acrylic acid, comprising at least the following steps: a. dehydration of glycerine to an acrolein-comprising dehydration product; b. gas phase oxidation of the dehydration product to obtain an acrylic acid-comprising monomer gas; c. bringing into contact of the monomer gas with a quench agent to obtain an acrylic acid-comprising quench phase; d. work-up of the quench phase to obtain an acrylic acid-comprising monomer phase; whereby, during the dehydration a liquid phase a1 and a gas phase a2 is present, whereby in the liquid phase a1 a plurality of gas bubbles is generated, as well as a process for production of polymers by polymerization of acrylic acid, preferably for production of water-absorbing polymers, the water-absorbing polymers obtainable by this process, a composite, a process for production of a composite, the composite obtainable by this process, and further chemical products.