摘要:
The invention relates to a process for the manufacture of unsaturated carboxylic acid esters by the reaction of olefins or cyclo-olefins with oxygen and carboxylic acids in the gaseous phase, in the presence of a catalyst which contains elements of the subsidiary group VIII of the periodic system and/or compounds thereof, and an alkali metal acetate, at temperatures of from 100.degree. to 250.degree. C. and pressures of from 0.5 to 21 bar absolute, wherein from 1 to 8000 parts per million (by weight), calculated on the carboxylic acid used, of organic chlorine compounds are added to the reaction mixture.
摘要:
In the chlorination of ethylene in the liquid phase, an excess stoichiometric amount of chlorine is normally used in order to achieve as complete as possible a conversion of the ethylene. Part of the excess chlorine reacts by substitution and thereby reduces the yield of desired 1,2-dichloroethane. The unreacted excess chlorine therefore has laboriously to be removed in subsequent reaction steps. As a result of the method according to the invention to limit the chlorine excess to less than 600 ppm by weight in the reaction cycle, these disadvantages can be obviated. The constant compliance with such a low chlorine excess without fluctuations is rendered possible in industrial operation by the arrangement according to the invention for the continuous recording of the chlorine concentration, even in the presence of catalysts.
摘要:
The invention concerns the use of redox-active compounds for the production of detection reagents for a method for the determination of an analyte as well as reagent kits that contain these redox-active compounds. In addition new redox-active compounds are disclosed.
摘要:
Non-blocking polymer pellets are produced in spherical or nearly spherical form by introducing molten polymer directly from a polymerization reactor into a coolant and pelletizing just prior to, simultaneously with, or immediately following entry into the coolant such that residual heat allows the polymer pellets to change their shape to eliminate sharp corners, particularly cylindrical shapes, and assume a spherical-type morphology.
摘要:
The invention relates to moisture-crosslinkable organopolysiloxane-polyurea block copolymers, to a process for preparing the crosslinkable organopolysiloxane-polyurea block copolymers, and to their use; to crosslinkable compositions comprising the crosslinkable organopolysiloxane-polyurea block copolymers, to the preparation of the crosslinkable compositions, to their vulcanization, and to the use of the vulcanizates.
摘要:
Amino group-containing organosilicon compounds containing no or only a small fraction of Si-bonded hydroxyl groups are prepared by preparing an organosilicon compound containing amino groups and Si-bonded hydroxyl groups by equilibration in the presence of an equilibration catalyst, and reacting the resultant product with a cyclic silazane. The products are particularly useful as a monomer or macromere for the preparation of high molecular weight organic polymers containing organosilicon blocks.
摘要:
Siloxane-urea copolymers are easily prepared by reacting a bis- or poly[azasilacyclopentyl]-terminated compound with a hydroxyl-functional compound followed by reaction with di- or polyisocyanate. When a bis[hydroxyl]-functional compound is used, the resulting polymer may be reacted with additional di- or polyisocyanate, optionally in the presence of additional isocyanate-reactive compounds such as chain extenders.
摘要:
A laminated glass comprises: A) at least one layer consisting of inorganic or organic glass and B) at least one layer consisting of a polysiloxane-urea copolymer which is obtained by reacting a mixture of linear polysiloxanes of general formula Q-T-SiR2O—(SiR2O)n—SiR2-T-Q and branched polysiloxanes of general formula (Q-T-SiR2O1/2)a(Q-T-SiRO2/2)b(Q-T-SiO3/2)c(R3SiO2/2)d(R2SiO2/2)c(RSiO3/2)f(SiO4/2)g with polyfunctional isocyanates. The laminates exhibit excellent moisture resistance.
摘要:
The invention relates to moisture-crosslinkable organopolysiloxane-polyurea block copolymers, to a process for preparing the crosslinkable organopolysiloxane-polyurea block copolymers, and to their use; to crosslinkable compositions comprising the crosslinkable organopolysiloxane-polyurea block copolymers, to the preparation of the crosslinkable compositions, to their vulcanization, and to the use of the vulcanizates.