摘要:
Olefins or mixtures of olefins, particularly propene or mixtures of propene advantageously with ethene, can be polymerized using a Ziegler-Natta catalyst system containing, besides a transition-metal-based procatalyst and cocatalyst which is an organometallic compound, a compound particularly suited for controlling the stereospecificity of the produced polymer. Such a compound called an external donor may also have other effects. By using an acetal derivative of an aldehyde that has two ether groups for this purpose, advantageously selected from the group of dialkoxyphenylalkanes, e.g., dimethoxyphenylpropane, a good stereospecificity of the product is attained combined with the high hydrogen sensitivity of the catalyst system, whereby the use of hydrogen as the chain transfer agent offers an easy control method of the molecular weight of the product by means of adjusting the amount of hydrogen available in the polymerization reaction. The acetal derivative is a compound according to formula (III): ##STR1## wherein R is C.sub.1-4 alkyl group, R.sup.1 and R.sup.2 are the same or different and each is a hydrocarbon group or a group which can together form a ring, R.sup.3 is hydrogen or a hydrocarbon group. If with the acetal derivative donor is used a clearly less hydrogen sensitive donor, e.g., alkoxysilanes, much broader MWD's of the product are achieved.
摘要:
Olefin polymerization catalysts the procatalyst component of which comprises a transition-metal compound on a magnesium chloride support material are known to all. Now the procatalyst component has been improved by incorporating a manganese (II) halide into it at a rate of at minimum approx. 0.1% and at maximum approx. 50% of the total molar amount of magnesium chloride and manganese (II) halide. The new polymerization catalyst has, among other things, the excellent special property that it yields a polyolefin with a broad molecular weight distribution.
摘要:
The invention relates to a method for preparing polyolefins. In the polymerization, a procatalyst composition is being used, which has been prepared by contacting MgCl.sub.2, a lower alcohol, a titanium compound and a phthalic acid ester. The polyolefin is given the adequate coarseness by using a procatalyst of the said type, which has been prepared by carrying out a transesterification between the lower alcohol and the phthalic acid ester and by selecting dioctyl phthalate (DOP) as phthalic acid ester.
摘要:
It is known that an electron donor together with a compound of tetravalent titanium on a magnesium halide carrier is usable if it is a mono- or polyester of an unsaturated polycarboxylic acid in which at least two carboxyl groups are joined to contiguous carbon atoms which form double bonds. It has now been observed that activity and stereospecificity increase if at least one of the said carbon atoms, or a carbon atom joined thereto by a double bond, is substituted by a hydrocarbon group having 1-20 carbon atoms. Maleic and fumaric acid esters substituted with the said hydrocarbon group can be mentioned as examples.
摘要:
When asymmetric olefins or a monomer mixture containing asymmetric monomers is polymerized by a catalyst composition containing esters of carboxylic acid e.g. as a so-called donor, and alcohol the ester group can be transesterified with the alcohol to an ester containing another alkyl group during the preparation and/or polymerization of the catalyst. This is advantageous particularly when an adduct of a so-called spray-crystallized Mg-halide and alcohol is used as the catalyst carrier, because the alkoxy group of the alcohol of the carrier and the alkoxy group of the ester of the donor can be transesterified and thus obtain the preferable effects of both esters on the run of the polymerization reaction. Hereby, a solvent having a high boiling point should be used as the intermediate agent, so that the transesterification reaction can take place. Most preferable have been found hydrocarbons having high boiling points, especially nonane and decane.
摘要:
In the invention a catalyst composition intended for the polymerization of olefins has been provided, which has been prepared by bringing together magnesium chloride, a lower alcohol, a titanium compound and an ester of phthalic acid. The procatalyst composition is active and stereospecific and it simultaneously has a titanium and phthalic acid content as low as possible. These good properties have been achieved by carrying out a transesterification between the lower alcohol and the ester of the phthalic acid, whereby the alkoxy group of the phthalic acid comprises at least five carbon atoms.
摘要:
The invention relates to a method for preparing polyolefins by polymerizing an olefin with a procatalyst composition prepared by bringing together MgCl.sub.2, a lower alcohol, a titanium compound and a phthalic acid ester. The invention also relates to a polyolefin obtained by polymerizing an olefin in the presence of a procatalyst prepared by bringing together MgCl.sub.2, a lower alcohol, a titanium compound and a phthalic acid ester, as well as to a procatalyst composition suitable for the preparation of a large-pore polyolefin, which composition has been prepared by bringing together MgCl.sub.2, a lower alcohol, a titanium compound and a phthalic acid ester.
摘要:
Ethene having a profitable .alpha.-olefin distribution and an .alpha.-olefin copolymer have been prepared with a process comprising reacting of at least the following components with each other:a) a procatalyst comprising a halogen compound of a transition metal in any of groups 4 to 8 of the periodic table of elements,b) a cocatalyst comprising an organohalogenous compound of a metal in group 2 or 3 of the periodic table of elements,c) ethene andd) one or more .alpha.-olefins copolymerizing with ethene, being characterised in that the organohalogenous compound of the metal in group 2 or 3 is prepared by reacting the organic compound of the metal in group 2 or 3 and a catalytically non-toxic halogen compound during copolymerization, or not earlier than 3 hours before copolymerization.
摘要:
A problem in the conventional olefin polymerization catalyst systems, the procatalysts of which are based on a solid carrier and a titanium compound and an electron donor on its surface, is that unsufficiently high activities are achieved by the morphology of the carrier. Moreover, the active age of such a catalyst in the polymerization is too short. These problems have now been solved by the olefin polymerization catalyst system according to the invention, the procatalyst of which comprises a solid carrier and a layer on its surface consisting of a titanium compound, a magnesium compound and an electron donor. The advantages of the invention become more emphasized when using monocyclopentadienyl titaniumtrichloride as the titanium compound.
摘要:
A catalyst for producing hydrogen gas from carbon monoxide and water, and a procedure for generating hydrogen gas from carbon monoxide and water in the presence of a catalyst. The catalyst is formed from a complex of a group VIII metal carbonyl and a heterocyclic base, and is of the formula M.sub.3-n M'.sub.n (CO).sub.12-x L.sub.x +yBwhereinM=RuM'=Fen is 0, 1 or 2x is 0, 1 or 2L is a triaryl or trialkyl phosphine or phospite,B is a chelating bidentate aromatic heterocyclic nitrogen-containing base, andy is a whole or fractional number from 1-6.