Abstract:
A method for smoothly and reliably initiating polymerization of ethylene with a supported chromium oxide catalyst, with smaller amounts of catalyst and in substantially shorter periods of time then heretofore required, by adding an alkylaluminum compound and ahydroxyl-containing compound to the reactor of a polymerization reaction system prior to the commencement of polymerization and subjecting said alkylaluminum compound and hydroxyl-containing compound to suitable conditions of temperature and pressure for a time sufficient for said alkylaluminum compound to react completely with the moisture present in said reactor and said hydroxyl-containing compound.
Abstract:
A male closure element comprising a U-shaped channel element including a profile portion (18) comprising a base portion (20) having a pair of spaced-apart, parallelly disposed webs (21) attached to the base portion (20) and extending therefrom, the webs (21) terminating in hooks (22) comprising hook portions (23) facing away from each other and hook projections (31) facing toward each other. The closure element may be employed with interlocking fastening devices to provide thereto improved ease of occlusion characteristics.
Abstract:
Stable, water-dispersible block copolymer coating compositions are produced from water-indispersible organic polymers having a plurality of hydroxyl groups and water-dispersible organic polymer having a plurality of carboxylic acid anhydride groups by controlled esterification.
Abstract:
High yields of excellent quality cyanohydrins can be prepared by reacting certain carbonyl compounds in a solution of metallic cyanide and hydrochloric acid.
Abstract:
Poly (aryl ether)s which contain at least 20% by weight of bis-(3,5-dimethyl-4-oxyphenyl) sulfone structural units exhibit improved glass transition temperatures, improved flame resistance, improved gas permeability and improved alloying compatibility.
Abstract:
Polymeric products having high tensile strength have been provided by forming a chemically non-cross-linked polymeric material with a theoretical tensile strength at break of at least 100 GPa by vapour deposition polymerization and drawing this material in a draw ratio above 10 in essentially oxygen-free conditions.
Abstract:
In the process for hydrocracking hydrocarbons boiling above about 700°F to midbarrel fuel products boiling system about 300°F and about 700°F which includes contacting the hydrocarbons with hydrogen under effective hydrocracking conditions in the presence of a catalyst composition comprising at least one hydrogenation component and at least one cracking component, the improvement which comprises utilizing as the cracking component an expanded clay including pillars comprising (a) at least one pillaring metal, (b) at least one rare earth element and (c) oxygen located between the sheets of at least one clay mineral or synthetic analogue thereof.
Abstract:
A process for the polymerization of a liquid alpha-olefin per se or in combination with one or more other alpha-olefins, which are themselves liquids or are dissolved therein, each alpha-olefin having 2 to 12 carbon atoms, comprising the following steps, step (a) being carried out in the liquid phase and step (b) being carried out in the gas phase: (a) admixing a catalyst comprising (i) a catalyst precursor, which includes magnesium, titanium, chlorine, and an electron donor; (ii) a hydrocarbylaluminum cocatalyst; (iii) a selectivity control agent, said selectivity control agent being different from the electron donor; and (iv) hydrogen with the alpha-olefin(s), the ratio, by weight, of alpha-olefin(s) to catalyst precursor being at least about 6,000:1, in a liquid phase reactor for a residence time in the range of about 10 seconds to about 400 seconds at a temperature in the range of about 20 DEG C to about 100 DEG C whereby the alpha-olefin(s) are partially polymerized; and (b) introducing the mixture from step (a) into at least one gas phase reactor at a temperature in the range of about 40 DEG C to about 150 DEG C in such a manner that the unpolymerized alpha-olefin is substantially polymerized.
Abstract:
Effluent gas streams for steam reforming, partial oxidation or coal gasification operations are advantageously treated in shift conversion, scrubbing and pressure swing adsorption units for recovery of a purified, hydrogen-containing product gas stream. By recycling a portion of the waste gas removed from the pressure swing adsorption system to the shift conversion unit and/or to the effluent gas generation operation, enhanced product recovery is achieved without the necessity for employing low temperature shift or for achieving essentially complete removal of the carbon dioxide content of the gas being treated prior to its passage to said pressure swing adsorption system.