The reactions of simple conjugated dienes over divalent and trivalent transition metal-exchanged montmorillonites yield, in the absence of nucleophiles, a variety of products. Some of these products are a result of Diels-Alder cycloaddition reactions, whereas others are indicative of carbocation intermediates, i.e., other dimers, oligomers, and isomerization products of these intermediates. The reactions in sealed cells between 20° and 150°C show trends in the yields of the various product groups. Dimers of butadiene and isoprene formed by cycloaddition (i.e., 4-vinylcyclohexene and the monoterpene p-menthadiene (limonene)) were formed at low temperatures (20–50°C). As the temperature was raised, the total yield of dimers increased and higher oligomers were formed along with isomerization products of the dimers and oligomers. The products of cycloaddition, however, did not increase markedly. The type of solvent used for the reaction was found to influence the reactivity, e.g., the use of 1,4-dioxan rather than chloroform led to a reduction in total conversion and also to a markedly higher degree of selectivity. In the presence of a suitable nucleophile (methanol), both dienes gave the 1,4-addition product predominantly, which suggests that an allylic carbocation intermediate was involved. The use of an interlayer-supported nickel complex, [HNi(P(OEt)3)4]+, produced the only large scale polymerization observed in this work.

In a Crowley silt loam, between 30 kPa, continuous flood, and alternate flood laboratory treatments at 25 C, dissipation of incorporated oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one] varied little, with an average of 59% remaining after 20 weeks. In the greenhouse, subsurface application of oxadiazon reduced its phytotoxicity but increased its persistence up to four times more than with surface-applied oxadiazon. In the field, 50% of the surface-applied oxadiazon dissipated from the soil within 6 to 11 days when the soil was flush irrigated and then flooded, compared to 15 to 17 days when the soil was irrigated but not flooded in two rice (Oryza sativa L.) management systems. Oxadiazon dissipation in the field was greater during the first 2 or 3 weeks after application than in the laboratory study. This is explained at least partially by the lack of herbicide incorporation in the field.

Gas-liquid chromatography was used to analyse the saponifiable and unsaponifiable fractions of petroleum ether (PE) extracts of neem fruits and leaves. Both fractions, as well as a crude PE extract, were assayed for biological activity against third instar cotton leafworm, Spodoptera littoralis.

In neem fruits, eighty-eight percent (88%) of the saponifiable matter consisted of saturated fatty acids, while 12% was composed of unsaturated fatty acids. In the neem leaves, the corresponding proportions were 62 and 38%, respectively. Unsaponifiable matter of both fruits and leaves contained varying amounts of hydrocarbons and sterols. All the tested extracts demonstrated significant larvicidal effects against leafworm larvae. They also prolonged larval duration, caused malformations of the resulting pupae and significant adverse effects on the fecundity of resulting adults.