Separ drying

Section 10.1 will consider the physical processes which oil and gas (and unwanted fluids) from the wellhead must go through to reach product specifications. These processes will include gas-liquid separation, liquid-liquid separation, drying of gas. 

The hardware items with which the processes described in Section 10.1 are achieved are called facilities, and are designed by the facilities engineer. The previous section described the equipment items used for the main processes such as separation, drying, fractionation, compression. This section will describe some of the facilities required for the systems which support production from the reservoir, such as gas injection, gas lift, and water injection, and also the transportation facilities used for both offshore and land operations. 

A fresh sample of dimethyl sulphate should be employed an old sample, or one that has been frequently exposed to the air, should be shaken with water, separated, dried over sodium sulphate, and distilled (b.p. 188"). 

Bromoform. Commercial bromoform should be shaken thoroughly with water, separated, dried over powdered anhydrous sodium sulphate and then fractionally distilled under reduced pressure using a water-condenser. It should be stored in a dark cupboard. It is an excellent solvent, has the advantage of a high Constant, and very seldom causes association of the solute. 

Nitrobenzene. Nitrobenzene, of analytical reagent quality, is satisfactory for most purposes. The technical product may contain dinitrobenzene and other impurities, whilst the recovered solvent may be contaminated with aniline. Most of the impurities may be removed by steam distillation after the addition of dilute sulphuric acid the nitrobenzene in the distillate is separated, dried with calcium chloride and distilled. The pure substance has b.p. 210°/760 mm. and m.p. 5 -7°. 

A further small quantity of n-heptyl alcohol may be obtained from the alkaline solution by mixing it with 50 ml. of water and distilling the distillate is saturated with salt, the oil separated, dried aad distilled from a small flask. 

An alternative method of working up the distillate, which has its advantages when dealing with volatile ketones or when it is suspected that conversion into the ketone is incomplete, is to treat the combined ketones with sodium hydroxide pellets until the mixture is alkaline. Should solids separate, these may be dissolved by the addition of a little water. The ketone is then separated, dried over anhydrous potassium carbonate, and fractionated. 

Pure dialkylanilines may be prepared by refluxing the monoalkylaniline (1 mol) with an alkyl bromide (2 mols) for 20-30 hours the solid product is treated with excess of sodium hydroxide solution, the organic layer separated, dried and distilled. The excess of alkyl bromide paases over first, followed by the dialkylaniline. Di-n-propylaniline, b.p. 242-243°, and di-n-butylaniline b.p. 269-270°, are thus readily prepared. 

In a 1 htre round bottomed flask equipped with a reflux condenser place a solution of 62 -5 g. of anhydroas sodium carbonate in 500 ml. of water and add 50 g. of commercial 2 4-dinitro-l-chlorobenzene. Reflux the mixture for 24 hours or until the oil passes into solution. Acidify the yellow solution with hj drochloric acid and, when cold, filter the crystaUine dinitrophenol which has separated. Dry the product upon filter paper in the air. The yield is 46 g. If the m.p, differs appreciably from 114°, recrystallisc from alcohol or from water. 

Free cydohexene from peroxides by treating it with a saturated solution of sodium bisulphite, separate, dry and distil collect the fraction, b.p. 81-83°. Mix 8 -2 g. of cycZohexene with 55 ml. of the reagent, add a solution of 15 mg. of osmium tetroxide in anhydrous butyl alcohol and cool the mixture to 0°. Allow to stand overnight, by which time the initial orange colouration will have disappeared. Remove the solvent and unused cydohexene by distillation at atmospheric pressure and fractionate the residue under reduced pressure. Collect the fraction of b.p. 120-140°/15 mm. this solidifies almost immediately. Recrystallise from ethyl acetate The yield of pure cis-l 2 cydohexanediol, m.p. 96°, is 5 0 g. 

Initial Run. - Into each of seven stoppered bottles was placed a mixture of ethyl sulphate [Et0-S02-0Et] (120 g.) and sodium nitrite [NaNOJ solution (120 g. in 160 c.c. of water.) The bottles were shaken mechanically for 20 hours, the pressure being released at intervals. The contents were then poured into a separating funnel, and the upper layer separated, dried over calcium chloride and distilled at 14mm., the distillate up to 60° being col-... 

A solution of 2-aminobenzophenone (98 g, 0.50 mol) and methyl 2-(methyl-thio)propanoate (74 g, 0,50 mol) in CH Clj (21) was cooled to —70 C and 95% 7-butyl hypochlorite (56 g, 0.5 mol) was added dropwise at such a rate that the temperature did not rise above — 65 C. One hour after the addition was complete, EtjN was added and the mixture was allowed to come to room temperature. The solution w as mixed with 3 N HCl (800 ml) and stirred for 1 h. The organic layer was separated, dried (Na2S04 ) and filtered. The solution was evaporated in vacuo and the residue triturated with ether. Filtration gave the 3-(methylthio)oxindole intermediate (92 g) in 62% yield. 

After all of the cyclohexylbromopropene has been run in, heating is continued for about two hours, the mixture is cooled and 500 cc. of ether is added. This mixture is poured on 1.5 kg. of cracked ice in a 5-I. flask and then acidified with 280 cc. of concentrated hydrochloric acid. The ether layer is separated, dried over calcium chloride and transferred to a i-l. modified Claisen flask (Org. Syn. 1, 40) for distillation. The ether is distilled at ordinary pressure and then the cyclohexylpropine under diminished pressure. The product boiling up to ii5°/2o... 

Optically pure I- and d-sec.-octyl alcohols are obtained by distillation in a current of steam of the -octyl hydrogen phthalate and 2 moles of sodium hydroxide in 30 per cent solution. The alcohols are practically insoluble in water and are separated, dried with potassium carbonate and distilled. Each boils at 86 /20 mm. and has a rotation (0)5461-1-11.8°, (a) -1-9.9° ( )546i (0)0 9-9°- The yields of alcohol from the sec.-... 

These can be converted to their uranyl nitrate addition compounds. The crude or partially purified ester is saturated with uranyl nitrate solution and the adduct filtered off. It is recrystallised from -hexane, toluene or ethanol. For the more soluble members crystallisation from hexane using low temperatures (-40°) has been successful. The adduct is decomposed by shaking with sodium carbonate solution and water, the solvent is steam distilled (if hexane or toluene is used) and the ester is collected by filtration. Alternatively, after decomposition, the organic layer is separated, dried with CaCl or BaO, filtered, and fractionally distilled under high vacuum. 

Acetal (acetaldehyde diethylacetal) [ 105-57-7] M 118.2, b 103.7-104 , d 0.831, n 1.38054, 1.3682. Dried over Na to remove alcohols and water, and to polymerise aldehydes, then fractionally distd. Or, treat with alkaline H2O2 soln at 40-45° to remove aldehydes, then the soln is saturated with NaCl, separated, dried with K2CO3 and distd from Na [Vogel J Chem Soc 616 1948]. 

Bis-(chloromethyl)oxacyclobutane [78-71-7] M 155.0, m 18.9 . Shaken with aqueous NaHC03 or FeS04 to remove peroxides. Separated, dried with anhydrous Na2S04, then distd under reduced pressure from a little CaH2 [Dainton, Ivin and Walmsley Trans Faraday Sac 65 17884 I960],... 

Fluorophenyl isothiocyanate [1544-68-91 M 153.2, m 24-26 , 26-27 , b 66 /2mm, 215 /atm, 228 /760mm, n 1.6116. Likely impurity is the symmetrical thiourea. Dissolve the isothiocyanate in dry CHCI3, filter and distil the residue in a vacuum. It can also be steam distd, the oily layer separated, dried over CaCl2 and distilled in vacuo. Bis-(4-fluorophenyl)thiourea has m 145 (from aq EtOH). [Browne and Dyson J Chem Soc 3285 1931 Buu Hoi et al. J Chem Soc 1573 1955 Olander Org Synth Coll Vol I 448 1941 ]. 

Steam distd from a soln containing 1-2 equivalents of 20% H2SO4 until about 10% of the base had been carried over with the non-basic impurities, then the acid soln was made alkaline, and the base separated, dried with NaOH and fractionally distd twice. Dried with Na and fractionally distd through a Todd column packed with glass helices (see p. 174). 

Methylfuran [534-22-5] M 82.1, b 62.7-62.8 /731mm, d 0.917, n 1.436. Washed with acidified satd ferrous sulfate soln (to remove peroxides), separated, dried with CaS04 or CaCl2, and fractionally distd from KOH immediately before use. To reduce the possibility of spontaneous polymeri.sation, addition of about one-third of its volume of heavy mineral oil to 2-methylfuran prior to distn has been recommended. 

Crystd from water by cooling to -5°, taking only the middle fraction of the solid which separated. Dried as the hexahydrate over 35-40% H2SO4 in a vacuum desiccator. 

For recovery of tetrahydrofuran, the condensate from the cooling traps and the low-boiling material from the fractionations are combined, cooled in an ice bath, and treated carefully with 15-20 cc. of 40 per cent alkali. The upper layer is separated, dried with a little calcium chloride, and distilled. The recovered tetrahydrofuran, b.p. 64-67°, weighs 20-22 g. (17-19 per cent of the original material). The residue (12-14 g-) remaining after disdllation of the tetrahydrofuran distils at 43-45°/io mm. and is tetramethylene dichloride. 

The amine, under the name N,N,N, N -tetramethyl-methylenediamine, may be purchased from Ames Laboratories, South Norwalk, Connecticut. The checkers prepared it by the following procedure. A solution of 60.7 g. (0.75 mole) of 37% aqueous formaldehyde solution is placed in an 800-ml. beaker equipped with a mechanical stirrer and thermometer, and cooled in an ice bath. Two hundred seventy-one grams (1.50 moles) of a 25% aqueous solution of dimethylamine is added to this solution at a rate such that the reaction temperature is kept below 15°. The solution is stirred for 30 minutes after the addition is complete, and potassium hydroxide pellets (approximately 150 g.) are added in portions until the reaction mixture separates into two layers. The upper layer is separated, dried over potassium hydroxide pellets overnight, and distilled to give 59 -64 g. (77-83%) of bis(dimcthylamin())mclliane, b.p. 83 84°. ... 

The organic layer is separated, evaporated on a steam bath, and the dark semicrystalline residue is distilled with steam to remove biphenyl. The contents of the steam-distillation flask are then extracted with ether (Note 3), and the ethereal layer is separated, dried over magnesium sulfate, and percolated through a short column of chromatographic alumina (Notes 4 and 5). Evaporation of the ethereal solution gives crude triphenylene which is sublimed at 175-180° and 0.1 mm. pressure. After rejection of an initial sublimate of impure biphenyl, the sublimed material forms nearly colorless crystals, m.p. 186-194° (Note 6). Yield 8-9 g. (53-59%). It may be further purified by recrystallization from a mixture of methylene chloride and pentane yielding colorless crystals, m.p. 199° (Note 7). 

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