Diethylene glycol hydrate removal

The carbonyl compound to be reduced (0.1 mole) is placed in a 250-ml round-bottom flask with 13.5 g of potassium hydroxide, 10 ml of 85% hydrazine hydrate, and 1(X) ml of diethylene glycol. A reflux condenser is attached and the mixture is heated to reflux for I hour (mantle). After refluxing 1 hour, the condenser is removed and a thermometer is immersed in the reaction mixture while slow boiling is continued to remove water. When the pot temperature has reached 200°, the condenser is replaced and refluxing is continued for an additional 3 hours. The mixture is then cooled, acidified with concentrated hydrochloric acid, and extracted with benzene. The benzene solution is dried, and the benzene is evaporated to afford the crude product, which is purified by recrystallization or distillation. 

Method A. Huang-Minlon modification of the Wolff-Kishner reduction. Place 36.0 g (0.3 mol) of redistilled acetophenone, b.p. 201 °C, 300 ml of diethylene glycol, 30ml of 90 per cent hydrazine hydrate (CAUTION) and 40g of potassium hydroxide pellets in a 500-ml two-necked round-bottomed flask fitted with a reflux condenser insert a thermometer supported in a screw-capped adapter in the side-neck so that the bulb dips into the reaction mixture. Warm the mixture on a boiling water bath until most of the potassium hydroxide has dissolved and then heat under reflux for 1 hour either by means of a free flame or by using a heating mantle. Remove the reflux condenser and fit a still-head and condenser for downward distillation. Distil until the temperature of the liquid rises to 175 °C (1). Separate the upper hydrocarbon layer from the distillate and extract the aqueous layer twice with 20 ml portions of ether. Dry the combined upper layer and ethereal extracts with magnesium sulphate, remove the ether on a water bath and distil the residue. Collect ethylbenzene at 135-136 °C the yield is 20 g (62.5%). 

A 500-ml. round-bottomed flask is attached by a well-lubricated ground-glass joint to a reflux condenser with a side take-off having a stopcock which may be opened to permit distillation. In the flask are placed 170 ml. of commercial diethylene glycol and 30 g. (0.46 mole) of potassium hydroxide (u.s.p., or reagent grade, 85%). This mixture is heated carefully (Caution Note 1) until the potassium hydroxide begins to melt and go into solution then the heat is removed intermittently until the exothermic dissolution is completed. After the solution has been cooled to 80-100°, the condenser is removed and there are added to the flask 35 g. (0.152 mole) of 6-ketohendecanedioic acid and 22 ml. (22.4 g., 0.38 mole) of commercial 85% hydrazine hydrate. 4 he condenser is immediately replaced, and the mixture is... 

A soln. of 7-keto-16-heptadecenoic acid, 80%-hydrazine hydrate, and some KOH in diethylene glycol refluxed 8 hrs., added to more KOH and diethylene glycol, water and excess hydrazine hydrate removed by distillation whereby the temp, rises to 185°, and refluxed an additional 15 hrs. 15-heptadecenoic acid. 

Water has to be removed from natural gas in order to prevent hydrate formation (which results in pressure loss and even plugging of gas conducts) and corrosion in pipelines. Generally containing around 500-1500 ppmv of water from the wellhead, natural gas has to be dehydrated up to 20-150 ppmv in order to prevent condensation or hydrate formation problems. So far, such an operation is realized by absorption on diethylene or triethylene glycol. This type of process is widely used in the gas processors community because of its very low investment and operating costs, as well as its reliability as an illustration, 40000 of those units are in operation nowadays on the US ground for natural gas conditioning. ... 

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