Funnel paragraph

B. Putrescine dihydrochloride. A 2-1. wide-mouthed Erlen-meyer flask containing 200 ml. of concentrated hydrochloric acid and 400 g. of cracked ice is clamped in an ice-salt bath and provided with an efficient stirrer (inefficient stirring may lower the yield). The stirring is started, and 80 g. (0.46 mole) of adipyl hydrazide is added all at once, followed by 500 ml. of ether (Note 5). While the temperature is maintained below 10° (Note 6), a solution of 80 g. (1.15 moles) of sodium nitrite in 150 ml. of water is added over about 30 minutes through a dropping funnel whose stem reaches below the bottom of the ether layer, but not into the path of the stirrer. The operations in the next paragraph should be conducted without delay after the completion of the addition of the nitrite. 

Escape from the minimum described in this paragraph is again possible in a variety of ways (e.g., path h in Fig. 3), and the process may go on for awhile before return to So from one of the minima or funnels finally occurs. 

Assemble a glass funnel filled approximately onehalf full with sodium sulfate such that the funnel will drain into the K-D concentrator or round bottom flask from Paragraph 9.6.4.1 containing the concentrated methylene chloride extract of the filtrate (You may use the same funnel from Paragraph 9.5.2 or 9.5.3). Pour the concentrated toluene extract of the particulates through the sodium sulfate into the K-D concentrator or round bottom flask. Rinse the flask from the particulate extract with three 15-20 mL volumes of hexane and pour each rinse through the sodium sulfate into the K-D concentrator or round bottom flask. 

Cool the vial thoroughly in an ice-water bath (10 min), stir the mixture with a spatula, and transfer the material from the vial to a Hirsch funnel under vacuum. Use two 1-mL portions of ice-cold absolute ethanol to aid the transfer and to rinse the product. Dry the crystalline trans,trans-l,4-diphenyl-l,3-butadiene by drawing air through the solid. The product has a small amount of sodium chloride that is removed as described in the next paragraph. The cloudy material in the filter flask contains triphenylphosphine oxide, the cis,trans-isomer, and some trans,trans product. Pour the filtrate into a beaker and save it for the thin-layer chromatography experiment described in the next section. 

Tli sensitivity of this method is so great that it is best to use doubly distilled water. Add 100 ml of such water to a separatory funnel and continue as described in Section E, paragraphs 2-6 inclusive. The extinction value should not exceed about 0.1-0.15. For surety at least one blank determination should be carried out with each batch of samples. 

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