The Dow Chemical Company

James R Dewald

Donald A Tomalia

Lowell D Markley

Dennis K Klipa

A method for preparing an .alpha.-substituted styrene such as 2-(3,5-dichlorophenyl)-4,4,4-trichloro-1-butene comprising contacting, an .alpha.-haloalkylbenzene such as 3-(3,5-dichlorophenyl)-1,1,1,3-tetrachlorobutane with a catalyst consisting essentially of .gamma.-alumina dried to a moisture content between about zero to about 12% by weight, the .gamma.-alumina serving to catalyze the dehydrohalogenation of the .alpha.-haloalkylbenzene to produce the .alpha.-substituted styrene.

Catalyst for dehydrohalogenation

Dense star polyamines having terminal group densities greater than extended conventional star polyamines exhibit greater and more uniform reactivity than their corresponding extended conventional star polyamines. For example, a second generation, amine-terminated polyamine dense star polyamine prepared from tri(2-aminoethyl)amine and aziridine has 4.7.times.10.sup.-3 amine moieties per unit volume (cubic Angstrom units) in contrast to the 1.7.times.10.sup.-3 amine moieties per unit volume contained by an extended conventional star polyamine. Such dense star polyamines are useful as calibration standards, high efficiency proton scavengers and in making size selective membranes.

Hydrolytically-stable dense star polyamine

Dense star polymers having terminal group densities greater than conventional extended star polymers exhibit greater and more uniform reactivity than their corresponding conventional star polymers. For example, a third generation, hydroxy-terminated polyether dense star polymer can be prepared from pentaerythrityltetrabromide and 4-hydroxymethyl-2,6,7-trioxabicyclo[2.2.2]-octane which has a molecular volume less than 80 percent of the volume of a conventional extended star polymer made from similar materials. Such dense star polymers are useful as demulsifiers for oil/water emulsions, wet strength agents in the manufacture of paper, proton scavengers, calibration standards for electron microscopy, and agents for modifying viscosity in aqueous formulations such as paints.

Dense star polymers having two dimensional molecular diameter

Dense star polymers having terminal group densities greater than conventional star polymers exhibit greater and more uniform reactivity than their corresponding conventional star polymers. For example, a third generation, amine-terminated polyamidoamine dense star polymer prepared from ammonia, methyl acrylate and ethylenediamine has 1.24.times.10.sup.-4 amine moieties per unit volume (cubic Angstrom units) in contrast to the 1.58.times.10.sup.-6 amine moieties per unit volume contained by a conventional star polymer. Such dense star polymers are useful as demulsifiers for oil/water emulsions, wet strength agents in the manufacture of paper, and agents for modifying viscosity in aqueous formulations such as paints.

Dense star polymers and dendrimers

Dense star polymer

Dense star polymers having core, core branches, terminal groups

3,5-Dichlorocumene is separated from a mixture comprising 3,5-dichlorocumene and 2,4-dichlorocumene by a process comprising contacting the mixture with an isopropyl group acceptor, in the presence of a catalyst comprising:

Separation of 3,5-dichlorocumene from a mixture of 3,5-dichlorocumene

In a mixture of isomers of ar,ar-dihalo-ar-alkylbenzene wherein the halogen substituents are meta oriented with respect to each other, (e.g., a mixture of 3,5-dichlorocumene and 2,4-dichlorocumene), the 2,4-dihalo-1-alkylbenzene is preferentially reacted with an alkylating agent, e.g., an alkyl halide, by contacting the mixture with the agent in the presence of a Friedel-Crafts catalyst at a temperature of less than about 90.degree. C. The resulting alkylated isomer is readily separated from the unreacted isomer(s) by simple distillation.

Process for separating an ar, ar-dihalo-ar-alkylbenzene from an isomeric

In a mixture of isomers of a disubstituted benzene such as dichlorobenzene, the meta-disubstituted isomer is preferentially reacted with an alkylating or acylating agent, e.g., an alkyl halide, by contacting the mixture with the agent in the presence of a Friedel-Craft catalyst at a temperature of less than about 60.degree. C. The resulting alkylated or acylated meta-isomer can be readily separated from the reaction mixture by simple distillation.

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Bay City, MI, United States of America

James R Dewald