摘要:
In a process for the preparation of copolymers of tetrahydrofuran and but-2-yne-1,4-diol by catalytic polymerization of tetrahydrofuran, the polymerization is carried out over a heterogeneous acidic catalyst which has acid centers of acidity pK.sub.a
摘要:
A process for the preparation of polytetrahydrofuran or polytetrahydrofuran monoesters of C.sub.1 -C.sub.10 monocarboxylic acids by the polymerization of tetrahydrofuran over a heterogeneous catalyst in the presence of one of the telogens water, 1,4-butanediol or polytetrahydrofuran having a molecular weight of from 200 to 700 dalton or a C.sub.1 -C.sub.10 monocarboxylic acid or mixtures of these telogens, wherein a supported catalyst is used as catalyst, which contains a catalytically active amount of an oxygen-containing tungsten or molybdenum compound or mixtures of these compounds on an oxidic support material and which was calcined at temperatures ranging from 500.degree. to 1000.degree. C. following the application of the precursor compounds of said oxygen-containing molybdenum and/or tungsten compounds to the support material precursor.
摘要:
Tetrahydrofuran/but-2-yne-1,4-diol copolymers containing C--C triple bonds and having an average molecular weight M.sub.n of from 500 to 3500 Dalton and a content of from 0.5 to 3 mol of triple bonds/mol of copolymer and blends of these copolymers with polytetrahydrofuran having an average molecular weight M.sub.n of from 500 to 3500 Dalton, processes for their preparation and their use.
摘要:
Polytetrahydrofuran, copolymers of tetrahydrofuran and 2-butyne-1,4-diol, diesters of these polymers with C.sub.2 -C.sub.20 -monocarboxylic acids or monoesters of these polymers with C.sub.1 -C.sub.10 -monocarboxylic acids are prepared by polymerization of tetrahydrofuran in the presence of one of the telogens water, 1,4-butanediol, 2-butyne-1,4-diol, polytetrahydrofuran having a molecular weight of from 200 to 700 Dalton, a C.sub.1 -C.sub.10 -monocarboxylic acid or an anhydride of a C.sub.2 -C.sub.20 -monocarboxylic acid or a mixture of these telogens over a heterogeneous supported catalyst which comprises a catalytically active amount of an oxygen-containing molybdenum and/or tungsten compound on an oxidic support material and which has been calcined at from 5OO.degree. C. to 1OOO.degree. C. after application of the precursor compounds of the oxygen-containing molybdenum and/or tungsten compounds onto the support material precursor, wherein the catalyst is activated by treatment with a reducing agent before it is used as a polymerization catalyst.
摘要:
A process for polymerizing cyclic ethers over a heterogeneous catalyst comprises using a heterogeneous catalyst comprising one or more pillared interlayered clays (PILCs).
摘要:
Polytetrahydrofuran, tetrahydrofuran copolymers, diesters or monoesters of these polymers are prepared by polymerizing tetrahydrofuran in the presence of at least one telogen and/or comonomer on a heterogeneous carrier catalyst which contains on an oxidic carrier material as active mass a catalytically active amount of at least one oxygenous molybdenum and/or tungsten compound and, when the precursor compounds of the active mass have been applied to the carrier material precursor, has been calcined at temperatures of between 500° C. and 1000° C. The catalyst used contains a promotor which comprises at least one element or a compound of an element of the 2nd, 3rd including the lanthanides, 5th, 6th, 7th, 8th or 14th group of the periodic system of elements.
摘要:
The invention relates to a method for producing polytetrahydrofuran, polytetrahydrofuran copolymers, diesters or monoesters of these polymers by polymerization of tetrahydrofuran in the presence of at least one telogene and/or comonomer on a sulfate-containing heterogeneous supported catalyst. A sulfate-containing heterogeneous supported catalyst is used containing at least one metal sulfate, metal hydrogen sulfate, metal oxide sulfate or mixtures thereof.
摘要:
In a process for preparing polytetrahydrofuran, polytetrahydrofuran copolymers or diesters or monoesters thereof comprises polymerizing tetrahydrofuran in the presence of at least one telogen and/or comonomer over an acid-activated calcium montmorillonite as catalyst, the calcium montmorillonite has a BET surface area of at least 300 m2/g, an acidity of at least 0.02 mmol/g at pKa
摘要:
In a process for preparing polytetrahydrofuran, tetrahydrofuran copolymers, diesters or monoesters of these polymers having a low color number by polymerization of tetrahydrofuran in the presence of at least one telogen and/or comonomer over a heterogeneous catalyst, the polymerization is carried out in the presence of hydrogen.
摘要:
In a process for preparing polytetrahydrofuran, polytetrahydrofuran copolymers or diesters or monoesters thereof by polymerization of tetrahydrofuran in the presence of at least one telogen and/or comonomer over acid-activated montmorillonite catalysts, the montmorillonite catalyst after acid activation has a ratio of montmorillonite structure to the sum of muscovite and kaolin structures, determined from the intensities of the reflections at 2&thgr;=5.5° for montmorillonite, 2&thgr;=9.0° for muscovite and 2&thgr;=12.5° for kaolin measured in the X-ray powder pattern, of at least 5:1.