Determination of fumigants. XX. Sorption of methyl bromide by potatoes

Abstract

in orange needles, from ethanol (found : Br 30.1%). The alcoholic filtrate from which the crude product had been obtained gave a heavy dark-red uncrystallizable Oil On dilution with water-Experiments in which the above large excess of bromine Was z : 7-Dibrotno-4 : ~-diinetl~i~~iorescein diacetate (a) Acefylation of tlie plieiiol.-A solution of z : 7-dibromo-4 : 5-dimethylfluorescein ( 5 . 2 g., 0.01 g. rnol.) in pyridine (50 c.c.) was treated with excess acetic anhydride (20.4 g., 0.2 g. rnol.), and heated on the steam bath for 2 hours. The reaction mixture was poured into water and the crude product twice recrystallized from acetone-ethanol, giving z : 7-dibroiiio-4 : 5-ditt1ethyl~itorescei~ diacetate, m.p. 282-284' (decomp.), in deep-yellow needles. Found : Br 25 .So/, ; C,,HI8OZBr, requires Br ~6.570/~.(b) Direct broniiiiatioii of 4 : 5-dinief~~;J'lfiioresceiti diacefate.-4 : 5-Dimethylfluorcrcein diacetate (6 g., 0.01 g. mol.), dissolved in glacial acetic acid (120 c.c.), was treated with a solution of bromine (3.5 g., 0.022 g. mol.) in aceticacid, at IOO' , and the solution maintdned at this temperature for I hour. On cooling and standing at oo overnight, the liquid dcpositcd a rcd crystalline solid which gave, on washing and recrystallization from acetoneethanol, 2 : 7-dibronio-4 : 5-diii~efl?v~itoresceifi diacetate, m.p. 282-286" (decomp.). Found : Br 26+040/. z : 7-Di-iodo-4 : 5-ditiietl?vlflriorescei?i 4 : 5-Dimethylfluorcscein (5.4 g., 0.015 g. mol.) was dissolved in sodium hydroxide solution (60 c.c., ~o j , wlv), and mixed wizh an alkaline solution of sodium hypoioditc, prepared by treating iodine (13 g., 0.05 g. mol.) with sodium hydroxide solution (60 c.c., Py0 w/v). The dark-red liquid was heated to IOO~, glacial acetic acid (25 c.c.) added dropwise with mechanical stirring, during 30 minutes, and the reaction mixture boiled for 5 minutes. After cooling to o", the solid was filtered off, reprccipitated by hydrochloric acid from its hot alkaline solution, and the crude product (7'5-8 g., i.c., 86y0 of the theoretical yicld) rccrystallized from acetone-ethanol. Minute needles of 2 : 7di-iodo-4 : ~-di)iietl?ylfliioresceiti, m.p. 263-265" (decomp.) were obtained. Found : I 40'9 ; C,,Hl4O& requires I 41 .s"/. 2 : 7-Di-iodo-4 : 5-dimcthylfluorcsccin was very sparingly soluble in water, dilute acids, and ethanol. It dissolved in hor xetone and ethanol and can be recrystallized from chlorbenzcne and bromobcnzene. Its alkaline solution is deep reddish-violet. 2 : 7-Di-iodo-4 : 5-dbiietl~il~icorescein diacetate The diacetate was prepared by the interaction of the phenol (6 g., 0.01 g. rnol.) and acetic anhydride (20.5 g., 0.5 g. mol.) in pyridine solution at ordinary temperature. Repeated crystall i d o n from glacial acetic acid gave a pale-yellow microcrystalline powder, m.p. 238-244' (decomp.). Found: I 36.3; C,,,HI8O7I, requires I 36.5%.3' : 6'-Dicliloro-4 : 5-dittietl?vlflitorcscei,r A finely powdered mixture of 2-methylresorcinol (1z.5 g., 0' I g. mol.) and 3 : 6-dichlorphthalic anhydride (14.2 g., 0....

CONTROL OF COLORADO POTATO BEETLE, LEPTINOTARSA DECEMLINEATA, IN SHIPMENTS OF HARVESTED POTATOES

“…Several other varieties have been found to be unaffected by fumigation with methyl bromide at dosages above these levels (Lubatti and Bunday 1958). As residual methyl bromide does not remain in fumigated potatoes for more than 24 h following treatment (Lubatti and Smith 1948) no residue problem would result from the treatment.…”

Fumigation of Shallot Seed with Methyl Bromide to Control Stem Eelworm, Ditylenchus dipsaci

“…The moisture content of the seed sample was 10 per cent and was therefore used without conditioning for the fumigation which was done in air-tight cylindrical metal chambers of 20 1 capacity (see Lubatti and Smith. 1948).…”

Gas Sorption by Soils and Clay Minerals

“…Lubatti and Smith (52) found a steady rise in sorption of methyl bromide as the soil approached water saturation. Han son and Hex (37) reported an increase in ethylene dibromide sorption by moist soil when the moisture level was increased and presumed that it was due to the solution of ethylene di bromide in the soil water.…”

“…Chisholm and Koblitsky (17), and Lubatti and Smith (52) demonstrated that dry soils adsorb more methyl bromide than wet soils. Stark (76) studied the adsorptive capacities of soils that had been exposed to different relative humidities and found greater adsorption of chloropicrin by the samples that had less moisture.…”