Reference

Characteristics of the kinetics of the anionic polymerization of nonpolar monomers in polar solvents

Characteristics of the kinetics of the anionic polymerization of nonpolar monomers in polar solvents. Podol'skii, A. F.; Taran, A. A.; Dashkin, R. Kh.; Bitsenko, M. I. (Inst. Vysokomol. Soedin., Leningrad, USSR). Vysokomol. Soedin., Ser. B, 19(1), 58-61 (Russian) 1977. CODEN: VYSBAI. DOCUMENT TYPE: Journal CA Section: 35 (Synthetic High Polymers) The nature of the active center is studied for the anionic polymn. of nonpolar monomers [.alpha.-methylstyrene (I) [98-83-9] butadiene [106-99-0], isoprene [78-79-5]] in the presence of org. Na or Li compds. and polar solvents [THF [109-99-9], dimethoxyethane (II) [110-71-4]]. A dependence of reaction order on catalyst concn. was obsd. and a mechanism was proposed which involved the formation of an intermediate monomer-catalyst complex with the reversible withdrawal of the nonpolar monomer from the coordination sphere by the strong electron donor solvent. 106-99-0 and 78-79-5 are also in the experiment. In the polymn. of I at -78.degree., the reaction order was 0.8 with respect to catalyst, but increased from 0.3 to 1.2 with respect to monomer on increasing the catalyst concn. from 0.001 to 0.05 mol/L. The use of a THF-II mixt. significantly increased the catalyst efficiency. .

Cyromazine-sensitive stages of housefly development: influence of penetration, metabolism and persistence on potency

Cyromazine-sensitive stages of housefly development: influence of penetration, metabolism and persistence on potency. Pochon, Jean Marc; Casida, John E. (Dep. Entomol. Sci., Univ. California, Berkeley, CA 94720, USA). Entomol. Exp. Appl., 34(3), 251-6 (English) 1983. CODEN: ETEAAT. ISSN: 0013-8703. DOCUMENT TYPE: Journal CA Section: 5 (Agrochemical Bioregulators) Cyromazine [5606-25-7] is a potent inhibitor of housefly (Musca domestica) larval development when administered orally to adults or incorporated into larval media, and of pupal metamorphosis on topical application shortly before or after pupariation. Pupae are most sensitive to cyromazine within 1 h after pupariation and with THF [109-99-9] as the carrier solvent, giving topical LD50 values of 3 mg/g for the total puparium plus pupa and 0.2 mg/g calcd. for the pupa only. THF is more effective than MeOH [67-56-1] in facilitating rapid cyromazine penetration during this crit. pupal stage. The rate of cyromazine penetration or accumulation at sensitive stages is more crit. than the extent of metab. in limiting cyromazine toxicity. Houseflies shortly after pupariation provide a sensitive and convenient organism for studies on cyromazine mode of action.