摘要:
A catalyst composition for living free radical polymerization. The catalyst composition includes a transition metal complex MXp and a ligand, wherein M is a transition metal; X is halogen, —NO2, —NCS, —NCO, —SCN, —CN, —N3, —SO4, carboxylate group, or —PF6; p is the valence of the transition metal, the ligand is represented by formula (I): wherein R1 can be the same or different and is C1-20 alkyl, C6-20 aryl, C7-20 alkylaryl, C7-20 arylalkyl, or heterocyclic groups; R2 can be the same or different and is H, C1-20 alkyl, C6-20 aryl, C7-20 alkylaryl, C7-20 arylalkyl, heterocyclic groups, alkyl sulfide groups, nitrile groups, alkylsilyl, or ester groups; n is an integer of 0 to 6; and A is deleted or an S or O atom, wherein the molar ratio of the transition metal complex MXp and the ligand is 1 to 4. The catalyst composition of the present invention can be used to polymerize (meth)acrylic, vinyl, vinylidene, and diene monomers, and the polymer obtained has narrow polydispersity.
摘要:
The disclosure provides a method for preparing the citraconic anhydride and a method for isomerizing/dehydrating itaconic acid. The method for preparing the citraconic anhydride includes the following steps: providing itaconic acid as a starting material; and subjecting the itaconic acid to an isomerization/dehydration reaction in the presence of a catalyst to obtain the citraconic anhydride, wherein the catalyst includes a heteropolyacid or heteropolyacid salt.
摘要:
A metallocene complex in which the cyclopentadienyl group is substituted with an alkanediyl silyl group. The yield of the metallocene complex is high, and it can be used as the catalyst for preparing high molecular weight olefin polymers.
摘要:
A catalyst composition for use in the preparation of poly(butylene terephthalate) from dimethyl terephthalate, comprising: (a) a titanium compound primary catalyst, from about 0.0005 PHR to about 5 PHR; (b) a first co-catalyst containing at least one of Zn, Co, Mn, Mg, Ca, or Pb series compounds, between about 0.0001 PHR and 5 PHR; and (c) a second co-catalyst containing an alkali metal phosphate, an alkali metal phosphite, an alkali hypophosphite, or an alkali metal polyphosphate between about 0.0001 PHR and 5 PHR; wherein PHR represents parts of the primary catalyst or the co-catalyst per one hundred parts, by weight, of dimethyl terephthalate. Preferred titanium compounds include tetrabutyl titanate or tetra(isopropyl)titanate. Preferred metal compounds for use as first co-catalyst are metal acetates. The alkali metal phosphate can be a phosphate salt containing one, two, or three metal groups; and the alkali metal phosphite can be a phosphite salt containing one or two metal groups. The alkali metal hypophosphite can be a hypophosphite salt containing any number of alkali metal groups. The alkali metal polyphosphate can be a polyphosphate salt containing one, two, three, four, or five alkali metal groups. With this catalyst composition, the rate of polycondensation was increased by 40 percent or more. The catalyst composition is also effective in the preparation of poly(butylene terephthalate) from terephthalic acid.
摘要:
A catalyst composition for use in a polycondensation reaction for making poly(ethylene terephthalate) from terephthalic acid comprising: (a) an antimony salt catalyst present in a range from about 10 to about 1,000 ppm; (b) a metal salt catalyst of at least one of cobalt, magnesium, zinc, manganese, calcium, and lead, present in a range from about 10 to about 500 ppm; and (c) an alkali metal acetate, present in a range from about 10 to about 500 ppm; all amounts are based on the metallic elements relative to the theoretical yield of the poly(ethylene terephthalate), by weight, to be made from the terephthalic acid. The catalyst composition was found to have increased the reaction rate in the production of poly(ethylene terephthalate), as well as improved the color of the produced product, by reducing the degree of yellowness in the final poly(ethylene terephthalate) product. Attenuation of the yellowish color indicates a reduction in the amount of undesired side reaction product.
摘要:
A catalyst composition for use in a polycondensation reaction for making poly(ethylene terephthalate) from terephthalic acid comprising: (a) an antimony salt catalyst present in a range from about 10 to about 1,000 ppm; (b) a metal salt catalyst of at least one of cobalt, magnesium, zinc, manganese, calcium, and lead, present in a range from about 10 to about 500 ppm; and (c) a phosphorus salt co-catalyst selected from the group consisting of alkali metal phosphates, alkali metal phosphites, alkali metal hypophosphites and alkali metal polyphosphates, present in a range from about 10 to about 500 ppm; all amounts are based on the metallic or phosphorus element relative to the theoretical yield of the poly(ethylene terephthalate), by weight, to be made from the terephthalic acid. The catalyst composition was found to have increased the reaction rate in the production of poly(ethylene terephthalate), as well as improved the color of the produced product, by reducing the degree of yellowness in the final poly(ethylene terephthalate) product. Attenuation of the yellowish color indicates a reduction in the amount of undesired side reaction product.
摘要:
The disclosure provides a method for preparing the citraconic anhydride and a method for isomerizing/dehydrating itaconic acid. The method for preparing the citraconic anhydride includes the following steps: providing itaconic acid as a starting material; and subjecting the itaconic acid to an isomerization/dehydration reaction in the presence of a catalyst to obtain the citraconic anhydride, wherein the catalyst includes a heteropolyacid or heteropolyacid salt.
摘要:
A process for hydrogenation of conjugated diene polymers comprises hydrogenating said polymer in the presence of hydrogen and a hydrogenation catalyst composition comprising: (a) at least one titanium compound represented by the following formula (a): wherein R1 and R2, which may be the same or different, represent a halogen atom, an alkyl group, an aryl group, an arakyl group, a cycloalkyl group, an aryloxy group, an alkoxy group or a carbonyl group, and Cp* represents a cyclopentadienyl group or a derivative having the formula of C5R5, and R5, which may be the same or different, represents a hydrogen atom, an alkyl group an aralkyl group and an aryl group; and (b) at least one silyl hydride.