摘要:
The initiation system comprises (1) at least one silylated initiator and (2) at least one alkaline metal alcoholate as ligand. The silylated initiator may be monofunctional and selected in particular from among the compounds of Formula (I) or difunctional and selected in particular from among the compounds of Formula (II): wherein R1, R2, R3 each independently represent a C1-C8alkyl radical, linear or branched; R4 is a linear or branched C1-C8alkylene radical; M is an alkaline metal or alkaline earth metal (valence q of 1 or 2); R5 and R6 each independently represent an alkyl radical, linear or branched, at C1-C8; R7, R8 each independently represent a C1-C8alkylene radical, linear or branched; M′ is an alkaline metal. Application is to the preparation of (meth)acrylic (co)polymers.
摘要:
A catalyst composition comprising (a) an iron-containing compound, (b) a dihydrocarbyl hydrogen phosphite, and (c) an organoaluminum compound is disclosed for polymerizing 1,3-butadiene into syndiotactic 1,2-polybutadiene. The use of the catalyst composition of this disclosure avoids the use of environmentally detrimental components such as carbon disulfide and halogenated solvents. The melting temperature of the syndiotactic 1,2-polybutadiene can be varied from about 100 to about 200° C. by variations in the catalyst components and the component ratios. The ability to vary the melting temperature over such a broad range with a single catalyst composition is very desirable. The syndiotactic 1,2-polybutadiene can be used as a plastic or as an additive for rubber compositions wherein it can crosslink with conventional rubbers using conventional crosslinking agents.
摘要:
The invention provides a process for commercial production of syndiotactic polyolefins using a metallocene catalyst supported on silica treated with MAO. The invention includes contacting the supported metallocene catalyst with an aluminum alkyl and aging the catalyst prior to polymerization. In addition, the catalyst is prepolymerized in a tubular reactor prior to being introduced into the polymerization reaction zone. The treated silica is produced by removing water to a level of 0.5-1.08%, slurrying in a nonpolar solvent, adding an alumoxane, heating to reflux, cooling the slurry, and separating the solid product.
摘要:
The invention provides a catalyst composition, comprising: (a) an organolithium compound; and, (b) an organic acid salt of lanthanide series element; wherein: (1) only components (a) and (b) are required to promote the synthesis of 1,4-trans-polybutadiene; (2) the ratio of component (a) to component (b) is selected to maximize formation of the trans structure of said 1,4-trans-polybutadiene; and, (3) components (a) and (b) are selected for enabling further diblock synthesis. The invention further contemplates a process for using the catalyst to synthesize 1,4-trans-polybutadiene and other polymers and copolymers having trans configuration in the conjugated diene monomer contributed units.
摘要:
Tin derivatives for use as oxygen-activated latent polycondensation catalysts. According to the invention, said tin derivatives have at least one tin-tin bond of the formula (I): R1—Yn—R4 wherein R1 and R4 which can be the same or different, are selected from hydrogen, and advantageously from the hydrocarbon radicals or together form a divalent radical or a single ring forming-bond; wherein n is at least equal to 2; wherein the Y, which are the same or different, stand for a stannic grouping having the structure (s): R′ and R″, which can be the same or different, are selected from hydrogen and advantageously from the hydrocarbon radicals. Application to paints.
摘要:
A catalyst composition comprising (a) an iron-containing compound, (b) a dihydrocarbyl hydrogen phosphite, and (c) an organoaluminum compound is disclosed for polymerizing 1,3-butadiene into syndiotactic 1,2-polybutadiene. The use of the catalyst composition of this disclosure avoids the use of environmentally detrimental components such as carbon disulfide and halogenated solvents. The melting temperature of the syndiotactic 1,2-polybutadiene can be varied from about 100 to about 200° C. by variations in the catalyst components and the component ratios. The ability to vary the melting temperature over such a broad range with a single catalyst composition is very desirable. The syndiotactic 1,2-polybutadiene can be used as a plastic or as an additive for rubber compositions wherein it can crosslink with conventional rubbers using conventional crosslinking agents.
摘要:
The present invention provides protected functionalized polymerization initiators having less than one molar equivalent chain extension agent introduced therein to provide hydrocarbon solubility.
摘要:
Methanol tolerant catalyst materials and a method of making the same are provided. These novel catalyst materials are obtained by mixing together and heat-treating at least two different transition-metal-containing nitrogen chelates. In preferred embodiments, the nitrogen chelates comprise metalloporphyrins such as transition-metal-containing tetraphenylporphins. Preferred transition metals are iron, cobalt, nickel, copper, manganese, ruthenium, vanadium, and zinc, but could be any transition metal other than platinum or palladium. These materials offer improved catalytic oxygen reduction in the presence of methanol, as may occur at a fuel cell cathode after methanol crossover.