2-Ethylhexyl acrylate was synthesized through direct esterification of acrylic acid (1) with 2-ethylhexyl alcohol (2), and through ester-interchange reaction between methyl acrylate (3) and (2). The high-boiling by-products were found to be 2-ethylhexyl β-(2-ethylhexyloxy)propionate (4) in the former case ; and (4), methyl β-(2-ethylhexyloxy)propionate (5), 2-ethylhexyl methoxypropionate (6), and methyl β-methoxy. propionate (7) in the latter case. Apparent activation energies were calculated to be 18.1 kcal/mol for the esterification and 13.9 kcal/mol for the ester-interchange. On the other hand, the values for the formations of (4), (5) and (6) were about 27.1, 13.4 and 14.3 kcal/mol, respectively. The activation energy for (7) formation could not be measured due to its extremely low reaction velocity. In the synthesis of 2-ethylhexyl acrylate by direct esterification, it is recommended to add sulfuric acid, a catalyst, at a level of 1 mol % and phenol, a polymerization inhibitor, at a level of 0.1 wt % of the (1) used. For ester-interchange reaction, the use of sulfuric acid, a catalyst, at a level of 1 mol % of the (2) used and sulfur, a polymerization inhibitor, at a level of 0.1 wt % of the (3) used is recommended. Those reactions are conducted at temperatures below 110°C to effect an approximately 95% yield.
Methyl 5-nitro-2-furylpropiolate was treated with alicyclic secondary amines to obtain the corresponding 5-nitro-2-furyl-β-aminoacrylates in a yield over 50%. Their structures were discussed based on their NMR, IR, and UV spectra. Though such amine-addition products were obtained with diethylamine, phenyl hydrazine, and ammonia, triethylamine, aniline, and N-methylaniline gave a different line of products. Intramolecular Diels-Alder reactions were attempted using 5-nitro-2-furylpropiolic acid in the presence of acetic anhydride or using its allyl ester. The former afforded only its anhydride, whereas the latter, the desired cyclic product.
Some effects of the substituents on the color and fastness of anthraquinone dyes derived from quinizarin-6-carboxylic acid have been studied. It is of interest to note the color change from reddish blue in 1, 4-disubstituted aminoanthraquinones to phthalocyanine-like sky blue in the analogous 6-substituted aminoanthraquinone dyes. Quinizarin-6-carboxylic acid was synthesized from trimellitic anhydride and hydroquinone through the Friedel-Crafts reaction. Dispersed dyes obtained from quinizarin-6-carboxylic acid showed moderate affinity to polyester fibers (Tetoron) and effected good level dyeing. They color Tetoron bright sky blue. Dyed fabrics showed excellent sublimation fastness and good light fastness.
Polyurethanes containing piperazine rings were synthesized from piperazine derivatives and diols. Diethyl piperazine-N, N'-dicarboxylate failed to give polymers, diphenyl piperazine-N, N'-dicarboxylate gave polymers of low molecular weight. Interfacial polycondensation between piperazine-N, N'-dicarbonyl chloride and diols gave polyurethaneureas, whereas melt polycondensation afforded polyurethanes. The polyurethanes derived from piperazine-N, N'-dicarbonyl chloride and Bisphenol A showed a m.p. of 278°C. It is insoluble in formic acid, chloroform, 2N sulfuric acid, 2N sodium hydroxide. It, however, is soluble in m-cresol.