Polyacrylamide was quantitatively hydroxymethylated with formaldehyde in an alkaline solution in the presence of catalytic triethylamine. This reaction in an acidic medium is proved unsatisfactory due to gel formation. The pH of the medium affected the reaction between N-methylol polyacrylamide and dimethylamine, slightly alkaline conditions being favorable. Thus, when the hydroxymethylated polymers were treated with dimethylamine in a molar ratio of 1:3 at pH 12, 70°C, for 0.5 hr, approximately 75% of the total methylol groups. were aminomethylated. In a more alkaline solution, the polymers tend to undergo hydrolysis to form carboxyl groups along the molecular chain. In an acidic solotion, on the other hand, gelation is unavoidable. N-Dimethylaminomethyl polyacrylamide is conveniently perpared by treating polyacrylamide with formaldehyde followed by dimethylamine withoutisolating the N-methylol intermediate. However, simultaneous treatment of polyacrylamide with both of the reactants is not recommendable because of the difficulty in controlling the reaction. N-Methylol and N-dimethylaminomethyl polyacrylamides are soluble in water and formamide, and insoluble in other organic solvents. The N-dimethylamino methyl polymer serves as a cationic polyelectrolyte.

View full abstract

Attempts have been made to synthesize 2, 3, 5, 6-tetrachlorotoluene, a starting compound for the preparation of 2, 3, 5, 6-tetrachlorophenylacetic acid, which has previously proved to be a potent hormonic herbicide. Since direct chlorination of toluene fails to introduce chlorine into the desired positions, 2, 3, 5, 6-tetrachlorotoluene has been synthesized from p-toluene sulf onylchloride through chlorination followed by hydrolysis. (1) Chlorination of p-toluene sulf onyl chloride proceeded with relative ease until three chlorine atoms had been introduced to the ring. Further chlorination was difficult due to increased viscosity of the reaction mixture. When the reaction temperature was raised, liberation of methyl and sulfonyl chloride groups started to occur to give highly chlorinated products such as pentachlorotoluene and hexachlorobenzene, the yield of desired product being lowered. (2) The by-products were separated from the product mixture by hydrolysis using steam with simultaneous steam distillation at a controlled temperature in the forms of 2, 3, 6-trichlorotoluene, pentachlorotolueue, and hexachlorobenzene. (3) Selective analysis of 2, 3, 5, 6-tetrachlorotoluene has been made possible by polarography, which serves as a simple and reliable means to detect the end point of the reaction.

View full abstract

In the light of the results of the preceding study, a further attempt was made to improve the chlori. nation reaction of p-toluenesulfonic acid into 2, 3, 5, 6-tetrachlorotoluene sulfonic acid in sulfuric acid. Sulfuric acid has thus proved to serve as a good reaction medium, and an improved yield (70-80%) was attained in a short reaction time. However, when the reaction temperature was 100-110°C or above, the formation of highly chlorinated by-products such as pentachlorotoluene was accelerated. At lower temperatures such as 50°C, essentially no reaction took place.

View full abstract