摘要:
A process for producing a Ziegler-Natta catalyst, the process comprising reacting an organo magnesium compound with a halogenated compound to produce crystalline magnesium halide having an intense diffraction line in an x-ray spectrum thereof at lattice distance within the range of from 2.56 to 3.20 Angstroms and titanating the magnesium halide by mixing the magnesium halide with a titanium compound whereby the titanated magnesium halide hasp in an x-ray spectrum thereof, a halo appearing at a lattice distance within the range from 2.56 to 3.30 Angstroms.
摘要:
A process for the preparation of a meso/racemic-(bis(indenyl)ethane zirconium dichloride compound comprising (a) reacting zirconium tetrachloride with the solid reaction product of the bis(indenyl)ethane ligand with an alkyllithium in a solvent as reaction medium and (b) recovering a solid mixture of lithium chloride and meso/racemic composition of (bis(indenyl)ethane) zirconium dichloride, characterized in that the solvent used as reaction medium in a reaction (a) is an ether, pentane or a mixture thereof.
摘要:
Powder compositions comprising about 5-15 wt % of PVdF-compatible thermoplastic resin, about 50-90 wt % of a thermosetting binder system, about 0-35 wt % of pigments and about 0-3 wt % of leveling agent are disclosed which are particularly suitable for use as primers with a later application of a pigmented PVdF-based top coating. Preferred compositions are based on an epoxy system containing about 8 wt % of PVdF or acrylic thermoplastic resin, 5-25 wt % of pigments and 0.7-1 wt % of leveling agent.
摘要:
The present invention relates to bituminous compositions used for roofing and waterproofing membranes or material comprising asymmetrical linear polyvinyl aromatic-polydiene block copolymers having improved physical properties over broader ranges of service temperatures than those obtained from bituminous compositions prepared with symmetrical block copolymers of similar type.The asymmetry of the copolymer which is characterised by polyvinyl aromatic endblocks of at least two different molecular weights, one high and one low, ensures improved physical performance to roofing and waterproofing membranes made from such compositions.
摘要:
Wet color cards prepared with water-based emulsion paints applied in layers of at least 75 g/m.sup.2 are dried using infra-red dryers irradiating the uncoated side of the cardboard or paper cards.
摘要:
Yeast cells whose DNA has been appropriately engineered to produce and to secrete lysozyme under control of a regulatable promoter are grown in the substantial absence of lysozyme synthesis and then are induced to produce and to secrete lysozyme under growth-limited conditions. This process is particularly suitable for the production of human lysozyme or mutants thereof.
摘要:
A new lipase and a new protease, which can be produced by a new Pseudomonas strain, and methods of producing such lipase and protease using said strain, protease, or producing enzymatic additives for detergents whose main active component is the lipase of the invention. Further disclosed are detergent washing compositions containing the lipase and/or the protease or the enzymatic additives, and a washing process using said compositions.
摘要:
A process for producing a catalyst for olefin cracking, the process comprising the steps of providing an MFI-type crystalline silicate catalyst, heating the catalyst in steam to remove aluminum from the crystalline silicate framework and extracting aluminum from the catalyst by contacting the catalyst with a complexing agent for aluminum to remove from pores of the framework aluminum deposited therein during the steaming step thereby to increase the silicon/aluminum atomic ratio of the catalyst; and calcining the catalyst at elevated temperature.
摘要:
A process for the production of olefins by catalytic cracking, the process comprising feeding a hydrocarbon feedstock containing at least one olefin of C4 or greater over a MFI-type crystalline silicate catalyst to produce an effluent containing at least one olefin of C2 or greater by catalytic cracking which is selective towards light olefins in the effluent, whereby for increasing the catalyst stability by limiting formation of coke thereon during the cracking process the catalyst has a silicon/aluminum atomic ratio of at least about 180, the olefin partial pressure is from 0.1 to 2 bars, and the feedstock contacts the catalyst at an inlet temperature of from 500 to 600° C. A process for increasing the stability of a MFI-type crystalline silicate catalyst, by limiting formation of coke on the catalyst, for catalytically cracking a hydrocarbon feedstock containing at least one olefin of C4 or greater to produce an effluent containing at least one olefin of C2 or greater, the process comprising pre-treating the catalyst so as to increase the silicon/aluminum atomic ratio thereof to a value of at least about 180 by heating the catalyst in steam and de-aluminating the catalyst by treating the catalyst with a complexing agent for aluminum.
摘要:
The present invention relates to a chromium/silca-aluminophosphate catalyst, titanated under specific conditions and used for the homopolymerisation or the copolymerisation of ethylene. The polyethylene obtained with this catalyst has a high melt potential and a high shear resistance. The catalyst has a high level of activity.