Abstract: A process for preparing hydrogen fluoride that involves treating anhydrous hydrogen fluoride containing primarily trivalent arsenic impurities with a sulfur compound capable of providing sulfide ions (e.g., H.sub.2 S) so as to precipitate the arsenic (i.e., as As.sub.2 S.sub.3) followed by separation and recovery (e.g., by distillation or filtration) of purified anhydrous hydrogen fluoride.

Abstract: There is here provided a method for manufacturing silane by subjecting a raw material, trialkoxysilane, to a disproportionation reaction in the gaseous phase in the presence of a catalyst which is an oxide of a metal in the third period of the periodic table. According to the present invention, silane can be obtained effectively without any by-products, and the reaction can be easily controlled and stopped promptly in an emergency.

Abstract: A process for the production of hydrides of magnesium, comprising reacting magnesium with hydrogen in the presence of magnesium.

Abstract: A process for the removal of carbon dioxide, hydrogen sulfide and alkyl mercaptans from a hydrocarbon-containing feed gas:(a) contacting the feed gas with an adsorbent capable of removing hydrogen sulfide and alkyl mercaptans from the feed gas at effective conditions to produce a treated gas having reduced concentrations of hydrogen sulfide alkyl mercaptans;(b) contacting the treated gas with a liquid medium capable of removing carbon dioxide hydrogen sulfide and alkyl mercaptans from the treated gas at effective conditions to produce a product gas having reduced concentrations of carbon dioxide hydrogen sulfide and alkyl mercaptans;(c) contacting a spent absorbent laden with hydrogen sulfide and alkyl mercaptans with a normally liquid fraction at effective desorption conditions to produce a regenerated adsorbent and a regeneration effluent having increased concentrations of hydrogen sulfide and alkyl mercaptans; and(d) utilizing the regenerated adsorbent as at least a portion of the adsorbent in step (a).

Abstract: Synthetic mazzite having a small particle size is advantageously prepared by making present a transparent liquid phase compound in a starting mixture containing a silica source, an alumina source, an alkali source and a tetramethylammonium source.The transparent liquid phase compound is obtained by mixing an aqueous solutuion of an alkali metal silicate, an aqueous solution of an alkali metal aluminate, an aqueous solution of an alkali metal hydroxide and a tetramethylammonium compound and aging the mixture.

Abstract: Crystalline molecular sieves having three-dimensional microporous framework structures of MO.sub.2.sup.n, AlO.sub.2, and PO.sub.2 tetrahedral oxide units are disclosed. These molecular sieves have an empirical chemical composition on an anhydrous basis expressed by the formula:mR:(M.sub.x Al.sub.y P.sub.z)O.sub.2wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "M" represents iron and/or titanium, and at least one of cobalt, magnesium, manganese and zinc; "n" is 0, -1 or -2; "m" represents the molar amount of "R" present per mole of (M.sub.x Al.sub.y P.sub.z)O.sub.2 ; and "x", "y" and "z" represent the mole fractions of "M", aluminum and phosphorus, respectively, present as tetrahedral oxides. Their use as adsorbents, catalysts, etc. is also disclosed.

Abstract: Silica aerogels which exhibit very little shrinkage or partial growth during processing and drying are produced by foaming and reacting a mixture of an oxidated silicon compound, a salt forming compound and a gas in an aqueous medium. The foamed silica gel is then dried to remove water thereby producing silica aerogel.The silica aerogels may be used as a thermal and sound insulator, filler, catalyst, catalyst carrier, reinforcing agent, binder, absorbent, thickening agent and may have other uses.

Abstract: A process for the manufacture of compounds of the general formula ##STR1## wherein R.sup.1 signifies hydroxy or an etherified hydroxy group, and of zeaxanthin by converting a compound of the general formula ##STR2## wherein R.sup.1 has the above significance, in an inert organic solvent into the acetylenide and reacting this with methyl vinyl ketone, reducing the alcoholate obtained or the alcohol (obtained after hydrolysis of the alcoholate) of the general formula ##STR3## wherein R.sup.1 has the above significance, and subsequently hydrolyzing to give the compound of formula IV and, if desired, converting the compound of formula IV obtained into zeaxanthin.

Abstract: A .beta..sub.2 microglobulin adsorbent composed of hydroxyapatite particles having an average size of 5 to 2,000 .mu.m is disclosed. The adsorbent preferably has a Ca/P ratio of 1.5 to 1.8.

Abstract: Crystalline molecular sieves having three-dimensional microporous framework structures of MO.sub.2.sup.n, AlO.sub.2, and PO.sub.2 tetrahedral oxide units are disclosed. These molecular sieves have an empirical chemical composition on an anhydrous basis expressed by the formula:mR : (M.sub.x Al.sub.y P.sub.z)O.sub.2wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "M" represents iron and/or titanium, and at least one of cobalt, magnesium, manganese and zinc; "n" is O, -1 or -2; "m" represents the molar amount of "R" present per mole of (M.sub.x Al.sub.y P.sub.z)O.sub.2 ; and "x", "y" and "z" represent the mole fractions of "M", aluminum and phosphorus, respectively, present as tetrahedral oxides. Their use as adsorbents, catalysts, etc. is also disclosed.

Abstract: Ferrisilicate molecular sieves of the ZSM-5 type, having SiO.sub.2 /Fe.sub.2 O.sub.3 mole ratios ranging from 20 to 400, are prepared by adding a silica source and a quaternary ammonium salt in that order to an acedified solution of an iron (III) compound, crystallizing the resulting gel to form a ferrisilicate molecular sieve, and thermally treating the molecular sieve with nitrogen, air and/or steam at 300.degree. to 700.degree. C. Preferred thermal treatment comprises treating with nitrogen first, then with air or steam. Thermally treated molecular sieves contain iron both in and outside the crystal framework; most of the non-framework iron is dispersed as very finely divided iron oxides on internal surfaces. Molecular sieves are useful as catalysts in Fischer-Tropsch and other iron oxide-catalyzied reactions.

Abstract: A process for forming carbides of silicon or metals in fine powder or whisker form. The process comprises forming a substantially uniform and non-agglomerated dispersion of a microfine powder of an oxide of silicon or a carbide-forming metal within a matrix of a polymer, carbonizing the oxide-containing polymer in an inert atmosphere and heating the carbonized product at high temperature to cause the oxide to react with carbon to form a carbide. The polymer must have a molecular weight of at least 10,000, a high carbon yield of at least 30% by weight, and a chemical structure which is infusible or capable of being rendered infusible. The preferred polymers are polyacrylonitrile, cellulose and polyvinyl alcohol, but other polymers with similar characteristics can be employed. The process is relatively inexpensive and gives an extremely finely divided product of high purity.

Abstract: An aromatic phosphine compound of the formula: ##STR1## wherein each of R.sub.1 to R.sub.3 is an aromatic group, or an oxide thereof.

Abstract: A process for producing an acrylic carbon fiber comprising the steps of applying an oiling agent comprising as its indispensable component a neopentyl alcohol derivative represented by the following general formula (I) to acrylic fiber, heating the lubricated acrylic fiber in an oxidizing atmosphere to convert the same into oxidized fiber, and heating the oxidized fiber in an inert atmosphere at a higher temperature to carbonize the same: ##STR1## The process can eliminate the defects of acrylic fiber precursor and provide a carbon fiber having excellent mechanical strength characteristics.

Abstract: A method of producing single crystals is characterized in that in withdrawing a semiconductor or dielectric material from its molten state while allowing it to grow into a single crystal solid, a die heated to a temperature higher than the solidifying point of the melt is disposed at the melt withdrawing outlet and the single crystal is withdrawn through the die.

Abstract: In a process for pulling a crystal such as Si, Ge, GaAs, InP, GaP, InAs, AlAs, CdTe, CdSe, ZnTe, HgTe, MnTe, Gd.sub.3 Ga.sub.5 O.sub.12, Bi.sub.12 SiO.sub.20 and LiNbO.sub.3 from a raw material melt within a baffle plate whose bore diameter is gradually increased upward and which is arranged in such a manner that the melt inside and outside the baffle plate is in communication with each other through the small opening part at the end thereof, the baffle plate is moved relatively to the surface of the melt so as to increase the diameter of the melt surface inside the baffle plate with the increase of the diameter of the pulled crystal at the solid-liquid interface.

Abstract: A combustion synthesis process for the preparation of .alpha.-silicon nitride and composites thereof is disclosed. Preparation of the .alpha.-silicon nitride comprises the steps of dry mixing silicon powder with an alkali metal azide, such as sodium azide, cold-pressing the mixture into any desired shape, or loading the mixture into a fused, quartz crucible, loading the crucible into a combustion chamber, pressurizing the chamber with nitrogen and igniting the mixture using an igniter pellet. The method for the preparation of the composites comprises dry mixing silicon powder (Si) or SiO.sub.2, with a metal or metal oxide, adding a small amount of an alkali metal azide such as sodium azide, introducing the mixture into a suitable combustion chamber, pressurizing the combustion chamber with nitrogen, igniting the mixture within the combustion chamber, and isolating the .alpha.-silicon nitride formed as a reaction product.

Abstract: A process for recovering alkali titanium fluoride salts suitable for commercial use from spent pickle acid liquors containing titanium by adjusting the fluoride to titanium mole ratio to critical ranges, adding an excess of alkali metal salt, and gently agitating the resulting solution at a temperature of at least 22.degree. C. to crystallize out the alkali metal titanium fluoride salt. The resulting filtrate can be neutralized with lime to yield a much reduced quantity of environmentally safe solid wastes compared with current neutralization practices where a titanium salt is not first recovered. (Optionally, in some cases, the filtrate can be recycled back to the acid pickling operation.) The liquid waste from filtering the neutral solids is low in metals and fluorides and generally acceptable for discharge to public treatment systems.

Abstract: Process for the manufacture of granular monohydrated sodium perborate, endowed with abrasion resistance, starting from the corresponding tetrahydrated perborate, characterized in that a carboxylic acid, containing from 1 to 3 C atoms, or an alkali metal salt thereof, is added to the tetrahydrated perborate, already present in the granular state, whereafter a dehydration of the tetrahydrated perborate is carried out.

Abstract: Molecular sieve compositions having three-dimensional microporous framework structures of BeO.sub.2, AlO.sub.2 and PO.sub.2 tetrahedral oxide units are disclosed. These molecular sieves have an empirical chemical composition on an anhydrous basis expressed by the formula:mR:(Be.sub.x Al.sub.y P.sub.z)O.sub.2wherein "R" represents at least one organic templating agent present in the intracrystalline pore system; "m" represents the molar amount of "R" present per mole of (Be.sub.x Al.sub.y P.sub.z)O.sub.2 ; and "x", "y" and "z" represent the mole fractions of beryllium, aluminum and phosphorus, respectively, present as tetrahedral oxides. Their use as adsorbents, catalysts, etc. is also disclosed.