Low‐molecular‐weight homopolymers of m‐bromophenylacetylene, as well as copolymers and networks of select di‐ and triethynyl benzenes with di‐ and tribromobenzenes, have been synthesized via a coupling reaction utilizing a palladium (II) salt, triphenylphosphine, cuprous iodide catalyst system.
Myrcene has been polymerized by treatment with triisobutylaluminum and titanium tetrachloride, triisobutylaluminum and vanadium trichloride, and by free radical initiation in emulsion systems. The polymers thus obtained vary in molecular weight range but all have a predominantly 1,4‐arrangement of the diene unit in the polymer chain. It is not possible to say whether this is a cis or trans structure on the basis of present information. Different samples of the polymyrcene obtained by the action of triioso‐butylaluminum and vanadium trichloride have inherent viscosities of 2 to 5.5. Myrcene polymerized by boron trifluoride etherate appears to have a cyclic recurring unit and is probably identical in structure with polymers prepared from β‐pinene by cationic initiation.
In connection with a study of aliphatic sulfinic acids as activators for Redox type polymerization (1) we have had occasion to prepare for the first time a pure crystalline aliphatic sulfinic acid, 1-dodecanesulfinic acid. Autenrieth (2) has reported the isolation of pure benzenesulfinic acid, but he found that the aliphatic acids were unstable, and did not accomplish their isolation. 1-Dodecanesulfinic acid appears to be considerably more stable than the lower alkanesulfinic acids but on standing for two months or on heating to 100°for a few hours it undergoes the disproportionation reaction reported for aliphatic sulfinic acids by von Braun and Weissbach (3) to yield 1-dodecyl 1 -dodecanethiolsulfonate (I) and 1-dodecanesulfonic acid. When an excess of sulfur dioxide was used in the 3CnH26S02H -> Gi2H25S02SCi2H25 + Ci2H2sS03H + H20 I preparation of the magnesium salt of the sulfinic acid from 1-dodecylmagnesium bromide by the procedure of Houlton and Tartar (4), the free sulfinic acid was formed and underwent disproportionation. The magnesium salt of the sulfinic acid was slowly oxidized in the air to the corresponding sulfonic acid salt.We also investigated the Ziegler and Connor (5) cleavage of ethane disulfones by sodium cyanide as a route to the salts of the higher aliphatic sulfinic acids. This reaction gave a good yield of sodium 1 -dodecanesulfinate but was unsatisfactory as a method of preparation of sodium 6-dodecanesulfinate.1-Dodecanesulfinic acid reacted with 1-dodecanethiol in boiling ether to produce a high yield of 1-dodecyl 1-dodecanethiolsulfonate. von Braun and Weissbach (3) write the equation for the reaction of n-butanesulfinic acid and benzyl mercaptan as follows:2C4H9S02H + 2C6H5CH2SH -> C4H9S02SC4H9 + C6H6CH2SSCH2C6H8 + 2H20In the case of our reaction between 1-dodecanethiol and 1-dodecanesulfinic acid this equation does not seem to account for the products isolated. When equal molar quantities of the two reactants were used the yield of thiol ester was double that which should be obtained on the basis of the von Braun equation. Also when 0.02 mole of acid and 0.0067 mole of mercaptan were used the yield was more than twice that possible in the von Braun reaction. No dodecyl disulfide was obtained in either experiment. Heating the sulfinic acid under the same conditions in the absence of the mercaptan did not yield the thiolsulfonate. These results support the views of Kharasch, Potempa, and Wehrmeister (6) that sulfenic acids are probable intermediates in reactions which involve sulfinic 1 Allied Chemical and Dye Corporation Fellow 1947-48.
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