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Insects and Mites Beware Sfauffer's new pesticide, now in pilot plant production, shows long residual action Now in the pilot plant stage i s a promising new pesti$Agricultural -&ftt~> phosphate ^ ^ ^ i S S S b t r V ^ S ; cide developed i^^SKM&Si^M ^> y Stauffer Chemical. Known as Compound R-1303 or Trithion, this material may have important use in the control of scale insects, mites, and aphids that attack citrus fruit, deciduous fruit, and ornamental plants. For the time being, however, i t can only be sold for application on ornamentals and other nonfood crops. Trithion is the p-ehlorophenylthiomethyl ester of o,o-diethyldithiophosphoric acid. Although the pure compound is a water-white liquid, the technical product from pilot plant production is a light yellow liquid o f 95% minimum purity, Trithion is toxic to a wide range of insects, mites, and eggs, L. W. Fancher of Stauffer told the Division of Agricultural and Food Chemistry. Field tests show that Trithion is especially promising for control of such pests a s clover mite, European red mite, wooly apple aphid, spotted alfalfa aphid, California red scale, yellow scale, and many others. On the other hand, Trithion is not effective against citrus bud mite, citrus thrips, cotton boll weevil, and the cabbage looper. Although Trithion is not a fast acting pesticide, it has a long residual effect. For example, two-spotted mites are unable to establish themselves on Trithion residues for as long as 28 days after t h e initial spraying. Various other phosphate pesticides at the same concentration lose their effectiveness after only a f e w days. T h e chance for reinfestation is further reduced because of t h e n e w compound's toxicity to e g g s and other stages of growth, says Fancher. Trithion is classed as a nonsystemic pesticide since it is not translocated throughout the plant system. This i s true in the case of beans, plums, apples, and citrus crops. Tests are under way to determine whether this nonsystemic property also applies to other crops. The new compound shows little or n o phytotoxicity t o apples, pears, peaches, plums, grapes, beans, cotton, and citrus fruits. $& P? 1
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A n important characteristic of a pesticide is its stability toward hydrolysis. In basic solutions, Trithion is hydrolyzed at different rates depending upon temperature and the solvents used. Even when the compound is kept for six hours at 65° C. in 1% aqueous sodium hydroxide, essentially no hydrolysis takes place. At 100° C , about 25% of the compound is hydrolyzed after six hours. In acidic media, the compound is highly stable.
Polynorbornene Depending on catalyst employed, norbornene polymerizes to either a flexible or stiff polymer Unexpected results came from experiments to make a stiff hydrocarbon polym e r. It was thought that norbornene [bicyclo (2,2,1) -2-heptene] would make a very stiff polymer if it could be polymerized. Being a cyclic material, the rigidity of the structural units and absence of flexible polymer backbone segments were expected to give the desired stiffness. When norbornene was polymerized using coordination-type catalysts, t w o distinct types of polynorbornene resulted, says I. M. Robinson of D u Pont. One type proved to be rigid with a more highly branched structure. T h e other type is a flexible polymer, having a comparatively simple structure. The type of polymer produced depends on the catalyst employed, Robinson told the Division of Polymer Chemistry's symposium on n e w olefin polymers last week. For most experiments Robinson and his collaborators used titanium tetrachloride and lithium aluminum tetraalkyl. With molar ratios titanium tetrachloride to lithium aluminum tetraalkyl greater than one, the rigid polymer was formed. At molar ratios less than one, flexible polymer resulted.
• Determining Structure. Both chemical and infrared studies were used t o elucidate the polymer structure and to form a basis for postulating the mechanism of polymerization. The simpler flexible polymer contains .oKo^o ~f _ / \ - C H = C H - . savs Robini i son. This structure results from a very unusual ring-opening reaction. The structure of the rigid polynorbornene is more complex, having more branching snu proc/a^xy srnaner amounts of the ring-opened structure, according to Robinson. It contains trans unsaturation, methyl groups, and vinylidene groups i n addition to more branching. Based on these structure studies, the polymerization mechanism involves coordination polymerization, a n e w type of mechanism as distinguished from free radical and ionic mechanisms. The monomer coordinates with an organotitanium compound formed from reaction of the tetrachloride with the tetraalkyl. An electron shift takes place and t h e titanium-carbon bond shifts, giving a carbon-carbon bond, the titanium moving t o a n e w position on the ring. Repetition of the process produces the polymer.
Primary Acid Standard Fisher Scientific's chemical manufacturing division is n o w offering a direct standard for acids. The n e w standard—Fisher Certified Tris(hydroxymethyl) - aminomethane— trade named Tham, has a minimum assay of 99.90%, melting point range of 170.9° to 171.3° C . For a 0.05M solution at 25° C , the p H is 10.4. Among advantages of Tham which company cites are ( 1 ) a high equivalent weight of 121.36; ( 2 ) l o w moisture pick-up; (3) doesn't absorb C 0 2 from air; ( 4 ) long shelf life (over two years if kept tightly c l o s e d ) ; ( 5 ) doesn't require further drying for ordinary laboratory standardizations. C1
IsobutyronitrHe Eastman Chemical Products now has commercial quantities of isobutyronitrile available t o the chemical industry. Produced at t h e Longview, Tex., plant of Texas Eastman, the compound is a water white liquid with a boiling range between 100° and 105° C . It is said to contain a maximum of 1.0% aldehydes ( a s carbonyl) and 0 . 8 % water. Specific gravity range ( 2 0 ° C./20° C.) i s 0.7690 to 0.7720. Initial production from the unit,
