Terminal Unsaturation in Polypropylene Glycol

Abstract

Vol. s1 indicated two OH bands a t 3.03 and 9.5 p and the C = 0 band a t 5.8 p .Infrared spectra of the products isolated from reduction of the dimers showed OH bands a t 3.0 and 9.5 p . The C=O band was absent in the spectra of these products. Experimental4Synthesis of Ketenes.-The ketenes employed in this study were synthesized by slight modification of the method reported previously.2 Physical constants and analyses of the ketenes are shown in Table I.Preparation of Derivatives of Ketenes.-Substituted hydrazides were prepared by treating samples of the ketene monomers with 2,4-dinitrophenylhydrazine reagent'; dihydrazones of the dimers were prepared similarly. Physical constants and nitrogen analvses of the 2,4-dinitrophenylhydrazides of the ketene monomers and the 2,4dinitrophenylhydrazones of the dimers are given in Table 11.Lithium Aluminum Hydride Reduction of Ketenes.-The procedure followed for reduction of the ketenes was essentially the same as that reported in an earlier study.1 T o a suspension of 2 g. (0.05 mole) lithium aluminum hydride in SO0 ml. of dry diethyl ether was added P-t-butylphenoxyn-butylketene monomer (17.4 g.). The reaction mixture mas heated for 21 hours, cooled, hydrolyzed, and extracted with ether. Distillation of the dried extract gave two re-(4) All melting pomts are corrected action products: @-t-butylphenol, b.p. 149-152" (9 mm.) (m.p. 95-96"); and 2-n-butyl-2-(p-t-butylphenoxy)-3-keto-

Synthesis and characterization of bio-polyols through the oxypropylation of bark and alkaline extracts of bark

“…The hydroxyl value for AB was 444 and for AAB was 408 mgKOH/g, and therefore, the amount of unsaturation is likely low due to the ligand effect of hydroxyls during the polymerziation. On the contrary, long chain glycols like PPG-2000 can have up to 4-20 olefinic terminal end-groups per 100 molecules (Dege et al, 1959). This should serve as a precaution for future work.…”

Practical and theoretical molecular weights in polyaddition reactions of ethylene and propylene oxide

“…If mt is the total moles of EO reacted, the following material balance exist: (8) where m, is the moles of starter. With md [eq.…”

Synthesis of biopolyols by mild oxypropylation of liquefied starch and its application to polyurethane rigid foams

“…However, it is known that under such severe conditions, monoalcoholic side products having unsaturated end groups can be formed. [8][9][10] The formation of these monoalcoholic products hinders the proceedings of crosslinking and polymerization during urethane resinification and results in a decrease in the physical properties of the urethane resins. The unsaturated end groups were shown to come from the isomerization of PO to allyl alcohol, which initiates new polymer chains.…”

“…The unsaturated end groups were shown to come from the isomerization of PO to allyl alcohol, which initiates new polymer chains. [8][9][10] Thus, the conditions of oxypropylation should be constrained to a much milder range.…”