CA Preparations

Alkyl propiolate couples with itself in the presence of catalytic DABCO under very mild conditions to provide a quantitative yield of E-hex-2-en-4-yne dioates. Hydrogenation of these enyne dioates using Lindlar catalyst provides the corresponding E,Z-diene dioate, a common structural motif found in an array of natural products.

Unsaturated carboxylic acids such as meth- acrylic acid, crotonic acid, vinylacetic acid, and sorbic acid and aromatic carboxylic acids reacted with terminal ace- tylenes in the presence of a catalytic amount of bis(05- cyclooctadieny1)ruthenium-P-n-Bui3n benzene a t 80 "C to give enol esters having a terminal methylene group in excellent yields with high regioselectivity.

This invention is directed to a fast curing polymer composition which does not require baking or thermosetting to provide a cross-linked coating binder. The composition comprises a polymer which is a homopolymer or copolymer of alpha, beta unsaturated monomers having pendent acetylenic groups which cross-link upon air drying to provide a coating binder.

The synthesis of methacrylates having an acetylene moiety activated by an electron-withdrawing group and a radical polymerization of the methacrylates are described. The methacrylates were prepared from alkynoic acids via ω-hydroxyalkyl alkynoates in two steps. This was done by the radical polymerization of the synthesized methacrylates, polymthacrylates having the acetylene moieties activated by the electron-withdrawing group as the side-chain that were obtained in high yields.

Phenolic materials containing propargyl groups are prepared by reacting a polyhydric, phenolic material with propargyl bromide, the reaction being conducted in an aqueous sodium hydroxide solution. The products can be thermally polymerized to polymers which are useful as adhesives and as matrix resins in the fabrication of composites

The conditions for the Knoevenagel synthesis of 2-cyanoacrylates containing double and triple bonds in the alkoxycarbonyl group have been studied. It was found that the esters are formed in 10–70 % yields by the condensation of the respective cyanoacetates with formaldehyde in the 1∶1 ratio in the presence of piperidine, followed by the pyrolysis of the oligomers formedin vacuo at 170–200 °C in the presence ofpara-toluenesulfonic acid.

Anionic polymerization of 2-propynyl methacrylate (1), 3-trimethylsilyl-2-propynyl methacrylate (2), 2-butynyl methacrylate (3), and 3-pentynyl methacrylate (4) was carried out in tetrahydrofuran at −78°C for 1 h. The employed initiator systems were (diphenylmethyl)potassium/diethylzinc (Et2Zn) and 1,1-bis(4′-trimethylsilyphenyl)-3-methylpentyllithium/lithium chloride (LiCl).

The thermal degradation of poly(allyl methacrylate) has been investigated using thermal volatilisation analysis (TVA), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The main pyrolysis products have been identified and the characteristics of the reactions deduced and discussed. Mechanisms have been proposed to account for the products formed.

Allyl methacrylate has been polymerized by free-radical methods and found to yield a soluble polymer in carbon tetrachloride, dioxane, and diallyl ether solutions. The overall rate equation in diallyl ether is Rp = k[ln]0.7[M]1.6. It is suggested that propagation and cyclization reactions proceed only via addition to the methacrylyl groups of the monomer. Some degradative chain transfer occurs with the allyl groups, and it is considered that the solvents may ensure the production of soluble polymers by reactions in which allyl–radical side chains are terminated without crosslinking.