Suspensions, pretreatment suspension heating

Compaction has little effect on the suspensibility of DDT powders when tested without accelerated-storage pretreatment however, when tested after accelerated-storage pretreatment, the suspensibility decreased with increasing compaction. The aged powders, although tested without heat treatment, exhibited the same pattern of loss of suspensibility with increased compaction as did the fresh powders after the accelerated-... 

Compaction of DDT powder has little effect on the suspensibility when the test is made on the fresh powder without a heat treatment however, after accelerated-storage pretreatment at 70 °C. for 2 hours, there is a consistent decrease in suspensibility with increasing compaction. Furthermore, compacted samples held in long-term storage exhibit the same pattern of loss of suspensibility as the samples subjected to accelerated-storage treatment. This is good evidence of the validity of the... 

In a 200-ml, two-necked, round-bottomed flask, copper powder (2.0 g, 0.0315 mol, 36 eq.) was pretreated for activation just prior to use (see Chapter 2). Dry DMF (30 ml) was added to the copper powder imder a nitrogen atmosphere, and the resulting suspension was heated to reflux temperature. The solution of (5)-551 (0.65 g, 0.864 mmol) in dry DMF (30 ml) was added dropwise over 8 h-period into the refluxing suspension of activated copper powder. After the addition had been completed, the reaction mixture was stirred under reflux for another 2 h. The reaction mixture was allowed to cool to room temperature, than it was diluted with benzene (50 ml), and filtered. Solids were washed with benzene. Combined organic phases were washed successively with 2 M HCl and water (3x), and dried over Na2S04 in the presence of activated charcoal. Evaporation of the solvent gave a pale yellow product (5,5)-552, 0.48 g (93.8 %), [a]o -201° (c = 1.03, benzene) [14]. 

Zhang C, Fevereiro PS (2007) The effect of heat shock on paclitaxel productimi in Taxus yunnanensis cell suspension cultiues role of absdsic acid-pretreatment. Biotechnol Bioeng 96 506-514. doi 10.1002/bit.21122... 

Ethyl Cellulose. Pretreated cellulose (100 g) was charged into a two liter stirrer pipe bomb, combined with NaOH (80 g, 2.0 M), ethyl chloride (250 g, 4.0 M) and 300 mL toluene and the mixture was heated to 130 for two hours. After cooling to 5 , the bomb was opened, excess ethyl chloride was allowed to evaporate and the residue poured into two liters of water. The toluene was steam distilled from the suspension and the ethyl cellulose was recovered by filtration. Approximately 46 g of ethyl cellulose, D.S. = 1.56, was obtained. A sample of ethyl cellulose prepared under identical conditions except omitting the catalyst was obtained in reduced yield (21 g) due to the higher water... 

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