background image
9
use as a nonaqueous reaction medium. DMS is particularly useful for utilizing soluble gases since
lower operating pressures are possible.

Ion Exchange Resins
Strong basic ion exchange resins have been prepared by chloromethylating bead form copolymers
of styrene and divinyl benzene followed by reaction with dimethyl sulfide. Treatment with alkali pro-
duces a basic resin containing benzyldimethylsulfonium groups.

Modification of Nylon Fibers
A physical and chemical modification of nylon fibers and fabrics may be accomplished by immersion
in a solution of DMS and zinc chloride. This treatment will delustre the fibers and make them more
receptive to dyeing. It is also claimed that the fiber surfaces will have a higher coefficient of friction, a
more rapid moisture pickup, and increased opacity.
1

Fiber Spinning
Polyvinyl chloride polymers can be dry spun or extruded after treatment with DMS and a ketone sol-
vent. Ageing of the polymer-solvent mixture produces a viscous solution which can be extruded di-
rectly into an atmosphere such that the solvent evaporates readily. Both DMS and the ketone sol-
vent are necessary with their proportions determined by the K value of the polymer.
2

Preparation of Carbonyl Cyanide
Carbonyl cyanide can be prepared easily and safely by reacting tetracyanoethylene oxide with DMS.
Additional information on this preparation will be found in Bulletin 203B, "Chemical Reactions of Di-
methyl Sulfide".

Catalyst Modifications
The presence of DMS can alter the course of reaction in certain catalytic processes.

A. Selective Hydrogenation
Ethylene which is produced by pyrolysis of natural gas contains varying amounts of acety-
lene. For most uses of ethylene, the acetylene must be removed. Hydrogenation using a pal-
ladium catalyst has been used to accomplish acetylene removal, but this is always accompa-
nied by undesired hydrogenation of ethylene to ethane. When DMS is added to the mixture, it
has been found that the hydrogenation of ethylene is suppressed while that of acetylene pro-
ceeds normally. The DMS is not decomposed by the treatment and does not have a perma-
nent effect on the catalyst.
3

B. Diolefin Polymerization
Materials consisting of a combination of an organo-metallic reducing agent and a reducible
compound of a heavy metal have been found to serve very well as catalysts for polymeriza-
tion of diolefins such as butadiene and isoprene. The polymers so produced have a structure
predominantly of the cis 1, 4 configuration. While these polymers are very useful for some
purposes, for other applications it is desirable to produce polymers having trans 1, 4 configu-
rations. It has been found that such polymers can be produced if the catalyst is modified by
the addition of DMS. To insure the 1, 4 configuration, it is also necessary to use iodine either