摘要:
The invention relates to a substrate provided, on at least a portion of one of its faces, with a coating with a photocatalytic property based on titanium dioxide which is at least partially crystalline and which is incorporated in the said coating partly in the form of particles predominantly crystallized in the anatase form. The invention also relates to a process for the preparation of this substrate and organic dispersions of titanium dioxide particles used in the said process for the preparation of the substrate.
摘要:
This invention relates to a process for obtaining pure or mixed oxide zirconia spheres, microspheres or washcoats consisting of: preparing a zirconium solution in water at a concentration, formally expressed as ZrO.sub.2, equal or lower than 400 g/l, starting from a basic zirconium carbonate additioned of conc. nitric acid up to a molar ratio �NO.sub.3.sup.- !/�Zr.sup.4+ ! between 0.8 and 1.1, and eventually preparing one or more solutions of the other oxides when necessary; preparing a sol of zirconium, eventually mixed to other metals, by a thickening agent and, in the case of spheres and microspheres, of a surface active agent too; dripping the sol into an alkaline gelation bath for obtaining gel spheres or microspheres, or sucking the sol into the honeycomb channels in order to obtain the washcoats, with subsequent gelation with gaseous ammonia; ageing the so obtained gel; rinsing with water down to pH=9-10, only in the case of gel spheres or microspheres; drying and calcining.
摘要:
The present invention provides a catalyst for the polymerization of olefin that exhibits improved selectivity and broader molecular weight distribution in the polymer product. The catalyst is a conventional supported Ziegler-Natta catalyst in combination with a mixture of at least two electron donors, both having the general formula SiR.sub.m (OR').sub.4-m where R is selected from the group consisting of an alkyl group, a cycloalkyl group, an aryl group and a vinyl group; R' is an alkyl group; and m is 0-3, wherein when R is an alkyl group, R may be identical with R'; when m is 0, 1 or 2, the R' groups may be identical or different; and when m is 1, 2 or 3, the R groups may be identical or different. This catalyst produces polypropylene having xylene solubles of 1-7 to 5.1 wt % and a molecular weight distribution of about 10.
摘要:
A process for the production of a mixed oxide powder, that contains as chief constituent TiO.sub.2 in the form of anatase and as minor constituents at least one of the catalytically active oxides MoO.sub.3, WO.sub.3 and V.sub.2 O.sub.5, suitable for use as a catalyst for the removal of nitrogen oxides, comprising (a) partially neutralizing a titanium dioxide hydrate suspension containing sulphuric acid with an alkaline liquor to a pH value between about 4.0 and 6.0 at temperatures between about 20.degree. and 100.degree. C., (b) filtering the suspension from (a) to produce a filter cake and intensively washing the filter cake, (c) adding to the filter cake from (b) at least one water-soluble salt of at least one of the metals Mo, W and V in solid or dissolved form, and (d) drying the filter cake from (c) and calcining it at a temperature between about 300.degree. and 750.degree. C.
摘要翻译:一种混合氧化物粉末的制造方法,其包含主要成分为锐钛矿形式的TiO 2和作为少量成分的至少一种催化活性氧化物MoO 3,WO 3和V 2 O 5的方法,适合用作除去 氮氧化物,其包含(a)在约20℃至100℃的温度下,将含有碱性液的硫酸的二氧化钛水合物悬浮液部分中和至约4.0至6.0之间的pH值,(b)将( a)生产滤饼并强烈地洗涤滤饼,(c)从(b)至少一种金属Mo,W和V的至少一种水溶性盐固体或溶解形式的滤饼中加入滤饼 ,(d)将(c)的滤饼干燥,并在约300〜750℃的温度下煅烧。
摘要:
A photocatalyst compound comprising a silica-based support material having bound thereto a photocatalyst selected from the group consisting of TiO.sub.2, WO.sub.3 and mixtures thereof, the photocatalyst compound having been derivatized by reaction with an alcohol compound. The process for producing the photocatalyst compound comprises the steps of: (i) contacting a silica-based support material having bound thereto a photocatalyst selected from the group consisting of TiO.sub.2, WO.sub.3 and mixtures thereof with an alcohol compound to form a slurry; (ii) maintaining the temperature of the slurry above the boiling point of the slurry to produce a substance having a modified surface consisting essentially of an alkyl silicate ester and esterified photocatalyst; and (iii) subjecting the substance to selective oxidation to oxidize the esterfied photocatalyst thereby producing a photocatalyst compound having a modified surface consisting essentially of an alkyl silicate ester and a photocatalyst substantially free of ester groups. The photocatalyst compound is useful, inter alia, in the treatment of a fluid containing an organic pollutant.