Amides mixed

Figure 2-25, to obtain 1 g of each amide required the reaction and separation of 18 g of cobester. The cobester was first reacted to obtain the amide mix. The preparative route shown on the left side of Figure 2-25 was first considered since the research group had extensive experience with preparative TLC. It involved a thick-layer plate separation followed by af-in. diameter LC column separation. The raw product is processed on thick-layer plates to separate the b-, e-, and f-fraction from the d-fraction. To separate 18 g of the reaction product by TLC, it is necessary to develop 240 thick-layer plates. Since each plate requires five sequences of elution and drying, the total operation requires 1200 elution and drying steps. The b-, e-, and f-amide is then separated using the high performance preparative column described in the center box in the lower third of Figure 2-25. To inject a total of 3 g of material to obtain 1 g each of the b-, e-, and f-amides, 20 preparative runs with 150-mg injections would be required.

FA-diethanol amide. Mixed coconut fatty acid (100% active)... 

Aliphatic aldehydes have been butylated enantioselectively using -butyllithium and chiral lithium amides. Mixed lithium amide-Bu Li complexes gave a faster asymmetric reaction, compared with Bu Li in the form of its tetramer. 

Table VI.l. Lanthanoid amides, mixed halide/amides and similar complexes.

In working up a complete reaction mixture, or filtrates from the amide, it is advantageous to remove water, organic solvent, and as much of the volatile ammonium sulfide as possible by evaporation to dryness on a water bath or by distillation under reduced pressure the residue contains the amide mixed with excess sulfur, small amoimts of the ammonium salt of the acid, and other by-products. Separation of the amide from the sulfur is accomplished usually by extraction with a solvent such as hot water, ethanol, or carbon tetrachloride which will dissolve the amide but not the sulfur. When such a separation is not feasible, it may be necessary to hydrolyze the amide to the acid by heating with aqueous or ethanolic alkali or with a mineral acid. A mixture of acetic acid and concentrated hydrochloric acid is particularly effective for the hydrolysis of insoluble amides. 

Several polymers other than PDMS and PVA have been examined for solid-polymer mixed-matrix pervaporation. An activated earbon-block polyether-amide mixed-matrix membrane was investigated for the separation of volatile organie eompounds (VOCs). An enhancement in both trichloroethane and water flux was noted, as well as increase in trichloroethane-water selectivity compared to the neat polymer. Zeolite-polyimide mixed-matrix membranes were explored for xylraie isomo- separation. Solid-polymer adhesion was poor, resulting in a sieve-in-a-eage morphology therefore, no separation properties that exceeded neat polymer membranes were identified. Methanol-toluene separation was successfully performed with NaX—Viton mixed-matrix membranes, though other solid-polymer combinations were attempted and failed to form an enhanced membrane. 

Chem. Descrip. Linear alkylbenzene sulfonate, coconut amide, mixed ethoxylated alcohols... 

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