Cooling separately

Another characteristic similar to A/ 100 is the Distribution Octane Number (DON) proposed by Mobil Corporation and described in ASTM 2886. The idea is to measure the heaviest fractions of the fuel at the inlet manifold to the CFR engine. For this method the CFR has a cooled separation chamber placed between the carburetor and the inlet manifold. Some of the less volatile components are separated and collected in the chamber. This procedure is probably the most realistic but less discriminating than that of the AJ 100 likewise, it is now only of historical interest. 

Furfuryl acetate. Reflux a mixture of 39 2 g. (34-8 ml.) of redistilled furfuryl alcohol, 48 g. of glacial acetic acid, 150 ml. of benzene and 20 g. of Zeo-Karb 225/H in a 500 ml. bolt-head flask, using the apparatus described under iaoPropyl Lactate. After 3 hours, when the rate of collection of water in the water separator is extremely slow, allow to cool, separate the resin by suction filtration, and wash it with three 15 ml. portions of benzene. Remove the benzene, etc., from the combined filtrate and washings under reduced pressure (water pump) and then collect the crude ester at 74-90°/10 mm. a small sohd residue remains in the flask. Redistil the crude ester from a Claisen flask with fractionating side arm pure furfuryl acetate passes over at 79-80°/17 mm. The yield is 14 -5 g. 

After allowing the mixt to cool, separate the red-colored ppt by filtn. Dissolve the crude product in hot ale and cryst by cooling. Recrystallize several times from eth... 

The resulting organic solution and the buffered bleach (16 mL) were cooled separately using an ice-bath and then combined at 4 °C in the flask. 

Another Zinc Reduction. Prepare or activate the zinc as follows 400 g of mossy zinc is treated with 800 ml of 5% aqueous solution of mercuric chloride for 1 hour. Decant the solution off and use the zinc right away. Add. 834 mole of compound to be reduced to the zinc amalgam, followed by as much HCl acid (.834 mole) diluted in as much water as is required to cover all the zinc. Reflux for 6 hours while adding small portions of dilute HCL acid. Cool, separate the upper, wash free of acid (a few portions of dilute sodium hydroxide), dry and distill to get about a 79% yield of product. 

QH, )aCH SCSNs, mw 285.40, N 14.7235 col crysts, mp 67° very sol in acet, EtOAc, benz, CSa, CHC1S or CCI4, moderately sol in ale, MeOH or eth. It was prepd by the interaction of benzohydryl bromide and Na azidodithiocarbonate. After filtering to remove the pptd NaBr, the yel liq, separated by the addn of w, was dissolved in eth and benz which, after drying and cooling, separated in small col crysts... 

W. Hittorf prepared metallic or violet phosphorus by heating phosphorus in contact with lead for 10 hrs. at a temp, near 500°. The phosphorus dissolves in the lead at the high temp., and on cooling separates from the lead in the form of small, dark, reddish-violet, rhombohedral crystals. The crystals can be separated from the lead by treatment with dil. nitric acid, which dissolves only the lead. The crystals are further purified by boiling them with hydrochloric acid. A. Stock and F. Gomolka recommended the following procedure ... 

Ethyl nitrite may be prepared by dissolving 38 g (0.55 mol) of sodium nitrite in 120 ml of water in a 500-ml flask equipped as above. Dilute 23 g (29 ml, 0.5 mol) of ethanol with an equal volume of water, carefully add 25 g (13.5 ml) of concentrated sulphuric acid and dilute to 120 ml with water. Cool both solutions to —10 °C in an ice-salt bath and add the acid-alcohol mixture to the nitrite solution slowly with constant stirring during about 30 minutes. Transfer the reaction mixture to a cooled separating funnel, run off- the lower aqueous phase, wash the ethyl nitrite layer rapidly with ice-cold 2 per cent sodium hydrogen carbonate solution and dry over anhydrous sodium sulphate. The product may be kept at 0°C as a 50 per cent solution in absolute ethanol if required but should be used as soon as possible. The b.p. of pure ethyl nitrite is 17 °C. 

Hexanoic acid. Into a 2-litre three-necked flask, fitted with a separatory funnel, a mechanical stirrer and a reflux condenser, place a hot solution of 200 g of potassium hydroxide in 200 ml of water. Stir the solution and add slowly 200 g (0.925 mol) of diethyl butylmalonate. A vigorous reaction occurs and the solution refluxes. When all the ester has been added, boil the solution gently for 2-3 hours, i.e. until hydrolysis is complete a test portion should dissolve completely in water. Dilute with 200 ml of water and distil off 200 ml of liquid in order to ensure the complete removal of the alcohol formed in the hydrolysis (2). To the cold residue in the flask add a cold solution of 320 g (174 ml) of concentrated sulphuric acid in 450 ml of water add the acid slowly with stirring in order to prevent excessive foaming. The solution becomes hot. Reflux the mixture for 3-4 hours and allow to cool. Separate the upper layer of the organic acid and extract the aqueous portion with four 150 ml portions of ether (3). Combine the acid layer with the ether extracts, wash it with 25 ml of water and dry with anhydrous sodium sulphate. Distil off the ether (rotary evaporator), transfer the residue to a flask fitted with a short fractionating column (the latter should be well lagged and, preferably, electrically heated) and distil the product from an air bath. Collect the hexanoic acid at 200-206 °C. The yield is 80 g (75%). Record the i.r. spectrum and compare it with that shown in Fig. 3.31. 

Cognate preparations. Butyl oleate. Proceed as for isopropyl lactate using 28 g (0.1 mol) of redistilled oleic acid, 37.0 g (46 ml, 0.5 mol) of butan-l-ol (the excess of the latter acts as the water carrier) and 8.0 g of Zerolit 225/H in a 250-ml flask. Reflux the mixture with magnetic stirring for 4 hours, allow to cool, separate the resin by suction filtration and wash it with three 5 ml portions of butan-l-ol. Remove the butanol from the combined filtrate and washings by distillation under reduced pressure (water pump) the residue consists of crude ester. Distil the residue under diminished pressure (oil pump) and collect the butyl oleate at 232 °C/9 mmHg. The yield is 27 g (85%). 

Cis, trans,m tricyclo[5.3.0.02,6]decane-3,8-dione. Dissolve 15 g (0.058 mol) of cis,trans,cis-3,3,8,8-tetramethoxytricyclo[5.3.0.02,6]decane in 225 ml of dichloromethane in a 500-ml two-necked flask equipped with a sealed stirrer unit and reflux condenser. Add 30 ml of 2 m hydrochloric acid and heat the stirred mixture under reflux for 1 hour. Cool, separate the organic layer and extract the acid solution with two 40 ml portions of dichloromethane. Combine the dichloromethane solutions and wash with 50 ml of 10 per cent aqueous sodium hydrogen carbonate and then 50 ml of water. Dry over magnesium sulphate, filter and remove the solvent on a rotary evaporator. Crystallise the residual solid from carbon tetrachloride cis,trans,cis-tricyclo-[5.3.0.02,6]decane-3,8-dione is obtained as white plates, m.p. 125-126.5 °C. The yield is about 9.1 g (95%). 

On distilling the clear extract over a water-bath, the petroleum ether is removed, and tho residue cm cooling separates in tables. It may be pnrifiod by recrystallisation from ether or benzene. 

---