Abstract:
PROBLEM TO BE SOLVED: To produce the subject compounds in high yield by using a solid acid catalyst, carrying out the conversion in the liquid phase and then separating the solid catalyst when conducting the rearrangement of a trimethylcyclohexenedione in the presence of an acylating agent and an acid. SOLUTION: A solid acid catalyst is used and the conversion is carried out in the liquid phase. The solid catalyst is then separated in a method for producing 2,3,5-trimethylhydroquinone diesters by rearrangement of 2,6,6- trimethylcyclohex-2-ene-1,4-dione in the presence of an acylating agent and an acid. Crystalline and/or amorphous aluminosilicates, clay minerals, pillard clays, etc., used in the H-form in each case are cited as the catalyst and an acid zeolite having 0.5-0.8 nm pore diameter is especially preferred.
Abstract:
The present invention relates to precipitated silicas which make it possible to produce storage-stable RTV-I silicone rubber formulations without stabilizer, a process for preparing them and their use for thickening sealing compositions.
Abstract:
Fumed silicon dioxide powder in the form of aggregated primary particles having a BET surface area of 175 ± 15 m2/g and a thickening effect, based on the BET surface area, of greater than 18 mPas g/m2 is hydrophobicized with polydimethylsiloxane. This hydrophobic fumed silica has a BET surface area of 110 ± 25 m2/g. It can be used in epoxy resins. These epoxy resins in turn can be used as adhesives.
Abstract translation:BET表面积为175±15m2 / g的聚合一次粒子形式的热解二氧化硅粉末和基于BET表面积的大于18mPas g / m 2的增稠效果用聚二甲基硅氧烷疏水化。 该疏水性热解法二氧化硅的BET表面积为110±25m 2 / g。 可用于环氧树脂。 这些环氧树脂又可以用作粘合剂。
Abstract:
Hydrophobic pyrogenic silica doped with potassium by means of aerosol is prepared by reacting a pyrogenic silica doped with potassium by means of aerosol with a surface-modifying agent. It can be used as a filler in silicone rubber.
Abstract:
The invention relates to pulverulent mixtures containing hydrogen peroxide and hydrophobed silicon dioxide, used to control the release of hydrogen peroxide and/or oxygen. The controlled release can be time-delayed or activated by the application of pressure. The invention permits hydrogen peroxide to be released in aqueous or pulverulent media and in emulsions, gels, creams or pastes.
Abstract:
Proceso para producir una sílice preparada de forma pirógena, modificada estructuralmente, silanizada que tiene grupos vinilo fijados a la superficie, grupos hidrófobos tales como trimetil sililo y/o dimetil sililo y/o monometil sililo fijados adicionalmente a la superficie y que tiene las siguientes propiedades fisicoquímicas: área superficial BET m2/g: 25 - 400 Tamaño de partícula primaria promedio nm: 5 - 50 pH: 3-10 % de contenido de carbono: 0,1-10 % de valor DBP:
Abstract:
Sílice de combustión silanizada por medio de dimetildiclorosilano, caracterizada por los datos fisicoquímicos siguientes: valor grindométrico menor que 20 μm densidad apisonada 25 a 85 g/l y obtenida de tal modo que una sílice de combustión que tiene los datos fisicoquímicos siguientes: superficie especifica BET, m2/g: 25-400 tamaño medio de partícula primaria, nm: 5-50 PH: 3-10 se silaniza por medio de dimetildiclorosilano y se tritura a continuación.
Abstract:
Ácido silícico de precipitación con una relación de extinción SiOHaislado mayor o igual que 1,5, una densidad degrupos silanoles de 1 a 3,0 SiOH/nm2 y una densidad apisonada modificada de 1 a 50 g/l, caracterizado porque éltiene un valor del pH de 3-5, estando excluido un ácido silícico de precipitación con un valor del pH de 4 - 5.
Abstract:
Ícido silícico de precipitación con las siguientes propiedades: -un valor d50 de 150 a 2000 nm;-un valor d90 de 500 a 7000 nm;-una densidad de grupos silanol de 2, 5 a 8 OH/nm2; y -una densidad en estado apisonado modificada menor que 70 g/l.