Vacuum distillation, see Distillation


In the traditional allyl chloride route, the allyl chloride may be converted into glycerol by two processes. The allyl chloride may be treated with aqueous chlorine, and the resulting mixture of glycerol dichlorohydrins dehydrochlorinated to epichlorohydrin [106-89-8/, which is then hydrolyzed to glycerol. In the second process, ahyl chloride is hydrolyzed to ahyl alcohol [107-18-6] (see Allyl ALCOHOL AND MONOALLYL derivatives). The ahyl alcohol is chlorohydrinated with aqueous chlorine solution to yield a mixture of monochlorohydrins which are hydrolyzed to glycerol in 90% yield based on allyl alcohol. The product from either of the above procedures is a dilute aqueous solution containing 5% or less of glycerol. High purity glycerol is obtained in several steps the cmde glycerol is concentrated to ca 80% in multiple-effect evaporators and salt is removed by centrifuging additional concentration of the product, followed by desalting, yields 98% glycerol colored substances ate removed by solvent extraction and the product is refined by steam-vacuum distillation (see ClD,OROHYDRINs).  [c.347]

The conventional mineral bases result from the refining of vacuum distillation cuts and deasphalted atmospheric residues. According to the crude oil origin and the type of refining they undergo, the structures of these bases can be essentially paraffinic, isoparaffinic, or naphthenic. The conventional scheme for lubricating oil production involves the following steps selection of distillates having appropriate viscosities, elimination of aromatics by solvent extraction in order to improve their VI (viscosity index), extraction of high freezing point paraffins by dewaxing and finally light hydrogen purification treatment (see Figure 10.13).  [c.277]

Attach the flask containing the mixture, with capillary in position, to the column make sure that the Perkin triangle (or vacuum distilling adapter ) and receiver are in place. See that the oil pump is functioning  [c.100]

In addition to the Perkin triangle and the Kon vacuum receiver already described (see Figs. II, 20, 1 and II, 20, 2), there are two modifications which are sometimes employed. The apparatus shown in Fig. II, 24, 6 is a standard form of all-glass Perkin triangle but with a water cooling jacket outside the receiver that in Fig. II, 24, 7 f has a similar function and four two-way stopcocks are utilised in its construction. Both of the last-named receivers are designed for use with low boiling point liquids, and are also useful for the distillation of small volumes of liquids since the side arm of the Claisen fiask, etc., may be fitted directly into the adapter. Another application is to the distillation of solids of low melting point warm water is then circulated through the glass jacket. It will be noted that a simple vacuum distillation receiver results if the apparatus of Fig. II, 24, 7 is constructed without the internal water jacket.  [c.119]

After 3 hours the stirring is stopped and the solution allowed to settle. By this time just about all the foil will have turned to dust, which is going to make the next step of vacuum filtration very difficult because it will plug up the filter paper in a second. So the chemist lets it settle, then pours off the liquid through the vacuum filtration setup (see methodology section). The flask is rinsed with lOOmL methanol, the methanol poured through the grey filter cake and the filter cake discarded. All of the filtrate is placed in a flask and vacuum distilled to remove all the methanol, isopropyl alcohol and water which will leave the chemist with oil and junk in the bottom of the flask.  [c.103]

A solution of 0.22 mol of butyllithium in 150 ml of hexane was cooled below -40°C and 140 ml of dry THF were added. Subsequently 0.20 mol of 1-dimethyl amino--4-methoxy-2-butyne (see Chapter V, Exp. 14) were added in 10 min with cooling between -35 and -45°C. After an additional 15 min 100 ml of an aqueous solution of 25 g of ammonium chloride were added with vigorous stirring. After separation of the layers four extractions with diethyl ether were carried out. The solutions were dried over potassium carbonate and then concentrated in a water-pump vacuum. Distillation of the residue gave a mixture of 8-10% of starting compound and 90-92% of the allenic ether, b.p. 50°C/12 mmHg, n 1.4648, in 82% yield (note 1).  [c.113]

Hove 1. The procedure described in Ref. 1 was modified. To a solution of 2.0 mol of lithium acetylide in 1.2 1 of liquid ammonia in a 4-1 round-bottomed, three-necked flask (see Fig. 2) was added 1.5 mol of freshly distilled benzaldehyde with cooling at about -45°C. After an additional 30 min finely powdered ammonium chloride (2 mol) was introduced in 15 min. The ammonia was allowed to evaporate, then water (1.1 1) was added and the product was extracted with diethyl ether. After drying over magnesium sulfate the extract was concentrated in a water-pump vacuum. High-vacuum distillation,  [c.178]

To a mixture of 25 ml of water and 3 ml of 95% sulfuric acid were added 40 ml of DMSO. The mixture was cooled to 10°C and 0.20 mol of l-ethoxy-l,4-hexadiyne (see Chapter III, Exp. 51) was added with vigorous stirring in 15 min. During this addition, which was exothermic, the temperature of the mixture was kept between 20 and 25 0. After the addition stirring was continued for 30 min at 3S C, then 150 ml of water were added and six extractions with diethyl ether were carried out. The combined extracts were washed with water and dried over magnesium sulfate. Evaporation of the solvent in a water-pump vacuum, followed by distillation through a 25-cm  [c.207]

Ultrafiltration/Diafiltration. This appHcation of membrane technology is normally carried out in a cross-flow mode using membranes of a nominal pore size in the molecular weight range 10 to 100, depending on the size of the protein being processed. Membrane systems are available in a number of formats, including hoUow fiber (see HOLLOW-FIBERMEMBRANES), spiral cartridge, and thin-channel (64,65). The performance of the operation depends on characteristics of the membrane, eg, pore size, porosity, strength, and hydrophobicity properties of the process solution, eg, the solubiHty and concentration of protein fluid mechanics (qv) at the membrane surface (66—68) and pressure difference across the membrane, which acts as the driving force (64,65). Ultrafiltration technology was introduced into plasma fractionation for the removal of residual quantities of ethanol from albumin solutions (69—72), as an alternative to methods such as freeze drying and vacuum distillation. The abiHty to remove solutes according to molecular size also enables ultrafiltration to be used in the diafiltration mode for the exchange of salts (73,74) and the removal of metal ions, such as aluminum (75,76). Similar technology has been introduced into processes for the manufacture of immunoglobulins (77,78) and coagulation factor concentrates (79—81). Ultrafiltration is generally regarded as the method of choice for the formulation of intermediate and final products. More recent attention has been directed toward further optimization of conditions (82), and the automation (83) and vaHdation (84) of the operation.  [c.530]

Distillation equipment for soap—lye and esterification cmde requires salt-resistant metallurgy. The soHd salt which results when glycerol is vaporized is removed by filtration or as bottoms from a wiped film evaporator. The Luwa scraped wall evaporator is capable of vaporizing glycerol very rapidly and almost completely, such that a dry, powdery residue is discharged from the base of the unit (8). Distillation of glycerol under atmospheric pressure is not practicable since it polymerizes and decomposes glycerol to some extent at the normal boiling point of 204°C. A combination of vacuum and steam distillation is used in which the vapors are passed from the stiH through a series of condensers or a packed fractionation section in the upper section of the stUl. Relatively pure glycerol is condensed. High vacuum conditions in modem stills minimize glycerol losses due to polymerization and decomposition (see Distillation).  [c.348]

Volatilization. In this simplest separation process, the impurity or the base metal is removed as a gas. Lead containing small amounts of zinc is refined by batch vacuum distillation of the zinc. Most of the zinc produced by smelting processes contains lead and cadmium. Cmde zinc is refined by a two-step fractional distillation. In the first column, zinc and cadmium are volatilized from the lead residue, and in the second column cadmium is removed from the zinc (see Zinc and zinc alloys).  [c.169]

The use of deuterium in nuclear reactors is discussed in detail elsewhere (see Deuterium and tritium). Fast neutrons, obtained by the fission of U, must be slowed to propagate the chain reaction or to react with U to produce plutonium (see Plutonium and plutonium compounds). Heavy water, D2O, is one of the most efficient of those substances that are able to accomplish this purpose. Methods of isotope separation include catalytic exchange between H2 and H2O, electrolysis, water distillation, hydrogen distillation, and various chemical-exchange systems (7,8). Quantities of D2O have been produced by catalytic exchange electrolysis and by vacuum distillation of water. The hydrogen sulfide—water, dual-temperature exchange process is used to produce multiton quantities of heavy water (9—13). Canada has built a number of large plants to furnish heavy water as a coolant and moderator of their CANDU (Canada—Deuterium—Uranium) power reactors. Other smaller plants in various countries employ water electrolysis, H2—NH exchange, water distillation, and hquid-hydrogen distillation (14) for deuterium concentration. Many plants use combinations of the above methods. Deuterium separation has been reviewed (15—17).  [c.198]

Manufacture. Polyesterether elastomers are made by a polycondensation reaction, either batchwise or by continuous polymerisation processes. The reaction proceeds in two steps, the first stage being an ester interchange followed by a polycondensation step, exactly analogous to the steps used in the manufacture of PET or PBT. The manufacture generally proceeds in the following manner. Dimethyl terephthalate (DMT), poly(tetramethylene oxide diol) (PTMEG), and excess butane-l,4-diol react in the presence of a titanium catalyst and the methanol evolved is distilled out of the reaction mixture (178). When the ester exchange is complete the reaction mixture is subjected to gradually diminished pressure to distill out the excess butanediol and drive the polymerisation to completion, eventually under full vacuum. The batch temperature must be kept below 250°C to avoid thermal degradation, and generally an antioxidant is added to protect the polyether segment from oxidative degradation (see Antioxidants). As the batch builds molecular weight, the melt viscosity increases and the power consumed by the agitator motor is taken as a measure of the degree of polymerisation. When the desired end point is reached, the vacuum is released with inert gas and the batch discharged under pressure through a die plate into molten strands which are cooled in a water bath and chopped into pellets for drying and bagging. The distilled methanol and butanediol can then be redistilled for recovery.  [c.304]

The basic raw materials for the manufacture of PMDI and its coproduct MDI is benzene. Nitration and hydrogenation affords aniline (see Amines, aromatic). Reaction of aniline with formaldehyde in the presence of hydrochloric acid gives rise to the formation of a mixture of oligomeric amines, which are phosgenated to yield PMDI. The coproduct, MDI, is obtained by continuous thin-film vacuum distillation. Liquid MDI (Isonate 143-L) is produced by converting some of the isocyanate groups into carbodiimide groups, which react with the excess isocyanate present to form a small amount of the trifunctional four-membered ring cycloadduct (9). The presence of (9) lowers the melting point of MDI to give a Hquid product.  [c.344]

The dibasic acids undergo the reactions typical of monocarboxyhc acids (see Carboxylic acids). The dibasic acids respond to heat by either losing one carboxyl group, yielding a monocarboxyhc acid, or dehydration to a cycHc or polymeric anhydride. A carbon suboxide, having a bis-ketene stmcture, may be formed under some conditions. CycHc anhydrides are formed by glutaric acid on heating or dehydrating with acetic anhydride or acetyl chloride. Heating adipic acid results in a high molecular weight polymeric anhydride that can be vacuum distilled to an unstable cycHc anhydride. Polyanhydrides are formed from all of the diacids of six carbons or higher when these are heated with acetic anhydride (26).  [c.62]

Heavy water [11105-15-0] 1 2 produced by a combination of electrolysis and catalytic exchange reactions. Some nuclear reactors (qv) require heavy water as a moderator of neutrons. Plants for the production of heavy water were built by the U.S. government during World War II. These plants, located at Trad, British Columbia, Morgantown, West Virginia, and Savaimah River, South Carolina, have been shut down except for a portion of the Savaimah River plant, which produces heavy water by a three-stage process (see Deuterium and tritium) an H2S/H2O exchange process produces 15% D2O a vacuum distillation increases the concentration to 90% D2O an electrolysis system produces 99.75% D2O (58).  [c.78]

To a mixture of O.BB mol of anhydrous lithium chloride and 100 ml of OMSO was added a solution of 0.40 mol of the acetylenic tosylate (for a general procedure concerning the preparation of acetylenic tosylates, see Chapter VllI-3, Exp. 3) in IBO ml of DMSO. The flask was equipped for vacuum distillation (see Fig. 5). Between the receiver, which was cooled at -75°C, and the water-pump was placed a tube filled with KOH pellets. The apparatus was evacuated (10-20 mmHg) and the flask gradually heated until DMSO began to reflux in the column. The contents of  [c.217]

Fair and Bravo [108] have performed extensive studies on structured packing and have developed general models for flooding, pressure drop, and mass transfer. Structured packing is now generally considered cost effective for moderate pressure and vacuum distillations when compared to trays and random packings [108]. The test work of the authors considered the trade-named structured packings of Intalox , Gempac , Flexipac , Mella-pak , Sulzer, and Montz in their studies. See earlier figures for installations of these packings, many of which are quite similar. All of the cited packings are corrugated sheet type designs, except the Sulzer, which is a fabricated wire gauze construction. Table 9-38 summarizes the characteristics of the selected packings. Refer to the respective manufacturers for confirming details and design application techniques.  [c.337]

The so-called hydro-vac pump, shown in Fig. 11, 22, 2 (the upper half of the mercury reservoir and the column above it are insulated by a layer of asbestos), is an inexpensive, all-glass, mercury diffusion pump, which can be used in series either with an oil pmnp or with a water Alter pmnp (compare Fig. 11,21, 1) capable of producing a vacuum of at least 2 mm. It is accordingly of particular value in the organic laboratory for vacuum distillations, fractionations, sublimations and pyrolyses as well as for molecular distillations (see Section 11,26). The hydro-vac  [c.111]

The next day comes and the hung-over chemist wakens to see a dark red solution stirring away. In some cases where the chemist had made an enormous batch of this stuff, there may be seen a small mass of crystalline precipitate at the bottom of the flask. This is no big deal and will go away in the next step. If the chemist had made this in a flat-bottomed flask (which she really should have for convenience) then the ice tray is removed, the flask returned to the stir plate, a distillation setup attached, and the acetone is vacuum distilled from the flask. After all the acetone has come over the chemist can proceed in two different ways. One way is to just keep on distilling the solution until all of the formic acid has been removed. The chemist knows that just about all the formic has been removed when there is about 300mL of thick black liquid remaining in the reaction flask and hardly any clear formic acid is dripping over into the collection flask. If one were to swirl the reaction flask, the liquid will appear syrupy and kind of coat the sides of the flask. This is more evident when the flask cools. A quick sniff of the flask may indicate that some formic is still in there, but it should be too minimal to be of any concern.  [c.55]

Technically, if the chemist wanted to do things by the book, she would extract the whole H2S04/oil solution with ether, then wash the ether with water. So the oil (which is now MD-P2P, by the way) is transferred to a small flask using ether and vacuum distilled (The oil is still very black with contaminants which need to be removed). After all the ether and water have come over and the receiving flask has been exchanged with a clean, new one, it may seem like an eternity for the oil to get hot enough to come over. But, eventually, the clear yellow oil front will start creeping up the glassware and into the condenser. About 250g (60%-70%) of MD-P2P will come over. The chemist knows its time to stop distilling when the oil flow starts to get a little orangy.  [c.57]

Well, that s about as rounded an education on Leuckart reactions as Strike can give. Strike feels that after reading all of those similar, repetitious steps, one can start to get a good feel for where a product is at any given moment. Stuff like what happens to MDA when it s mixed with acid or base, or what happens to ketones (P2P) under the same circumstances. One can see now that it is possible to not only isolate safrole and P2Ps chemically but that the same can be true for the final MDA or meth freebase oil. Repeated washings with acid or base and solvent can effectively clean up a compound to an almost presentable state without the use of vacuum distillation, it can happen, one only needs have confidence in the chemistry.  [c.116]

What the chemist will see is two layers a solvent layer (THF or Et20) and a water layer with a lot of suspended solids. The chemist can remove and discard the aqueous layer now or, preferably, the chemist can vacuum filter the entire two-layered solution to get rid of all the solids, then remove the water layer. Of course it is always a good idea to extract that water layer once with fresh solvent before it is discarded. The solvent/safrole layer is washed with a little dilute HCI and then with some fresh dH20. The solvent layer is then dried through Na2S04 and vacuum distilled. The first thing to distill over is, of course, the solvent. The next thing to come over will be a few mLs of a low boiling oil which is going to be 1,3-benzodioxole and will be saved for reuse. At a much higher temperature comes all the safrole. The chemist will have no trouble knowing that the procedure worked because all of that high-boiling oil is going to smell just like licorice (yield=87%).  [c.234]

What the chemist has is an alcohol intermediate which is not what she wants. If she were to flick off that OH group then a double bond will form in its place and isosafrole or propenylbenzene will be borne [26], So what the evil chemist does is place 60g of the alcohol intermediate oil and 1g potassium bisulfate (KHSO4) into a really small flask, attach the flask to a distillation apparatus and start heating with vacuum. As the OH group is being kicked out it will form water, which the chemist will see distilling over. When no more water can be seen evolving then the reaction is finished. However, the chemist continues to heat to distill over all of the isosafrole which will smell just like licorice (yield=91% from the intermediate). If the chemist wanted to she could perform the same bisulfate procedure in a beaker or flask without the distillation setup and stop the reaction when a temperature of 170°C has been reached [28 p698]. The oil is still going to have to be distilled to purify it though.  [c.239]

To a solution of 0.5 mol of potassium amide in 2 1 of liquid ammonia (prepared as described in Chapter II, Exp. 12, and subsequently freed from small pieces of potassium by filtration through glass-wool) was added in about 5 min a solution of 0.20 mol of 2-butynoic acid (see Exp. 35) in 150 ml of liquid ammonia. During this addition, which was carried out by pouring the solution into the solution of potassium amide, both outer necks of the reaction flask were open. The ammo-niacal solution of the acid was prepared by addition of the required amount of anhydrous liquid ammonia to the acid in a 500-ml round-bottomed flask. After the addition of the dissolved acid to the potassium amide the reaction flask was provided with the dropping funnel and gas outlet, as indicated in Fig. 2. The thick, greyish suspension was stirred for 90 min, then a mixture of 0.25 mol of methyl iodide and 100 ml of diethyl ether was added in 10 min. A considerable part of the suspended material passed into solution. Ten minutes after the addition of the methyl iodide the dropping funnel and gas outlet were removed and 100 g of powdered ammonium chloride were introduced in small portions with vigorous stirring. The ammonia was evaporated by warming the flask in a water--bath at 45 C. In order to effect complete removal of the ammonia, the flask was evacuated by means of the water pump as soon as the stream of escaping ammonia vapour had become faint. During the evacuation, which took about 1 h. the flask was immersed in a water-bath at 40°C. The remaining solid material was dissolved in 300 ml of ice-water, then the solution was acidified to pH 1 with 3 N hydrochloric acid. The mixture was then extracted ten times with diethyl ether and the ethereal extracts were dried (without previous washing) over magnesium sulfate and subsequently concentrated in a water-pump vacuum. Distillation of the remaining liquid in a high vacuum (0.1-0.5 mrnHg) gave 18 g of crude product, which was dissolved in 50 ml of pentane. After standing for 12 h at -25 to -35°C the crystal 1ine material was sucked off on a sintered-glass funnel. After drying in a water-pump vacuum the m.p. was 47-48 C. From the mother liquor a second batch of reasonably pure product was obtained, making the yield 45. .  [c.35]

A solution of a-lithiomethoxyallene was prepared from nethoxyal lene and 0.20 mol of ethyllithiurn (note 1) in about 200 ml of diethyl ether (see Chapter II, Exp. 15). The solution was cooled to -50°C and 0.20 mol of ethylene oxide was added immediately. The cooling bath was removed temporarily and the temperature was allowed to rise to -15 c and was kept at this level for 2.5 h. The mixture was then poured into 200 ml of saturated ammonium chloride solution, to which a few millilitres of aqueous ammonia had been added (note 2). After shaking the layers were separated. The aqueous layer was extracted six times with small portions of diethyl ether. The combined ethereal solutions were dried over sodium sulfate and subsequently concentrated in a water-pump vacuum. Distillation of the  [c.39]

To a solution of Q.26 mol of ethyllithium (see Chapter 11, Exp. 1) in 200 ml of diethyl ether was added 0.12 mol of benzyl acetylene (see Chapter VI, Exp. 38) with cooling between -20 and -40°C. After the addition the brov/n solution was kept for 2 h at 15°C. It was then cooled to -45°C and 0.12 mol of freshly distilled trimethylchlorosilane v/as added in 10 min, while keeping the temperature of the reaction mixture at about -40°C. The cooling bath was then removed and after an additional 30 min the mixture was poured into ice-water. The upper layer, formed after shaking, was separated. The aqueous layer was extracted with diethyl ether and, after drying the combined solutions over magnesium sulfate, the diethyl ether was evaporated in a i/ater-pump vacuum. Distillation of the residue through a 30-cm Vigreux column afforded the desired compound, b.p. 102°C/18 mmHg, Op 1.5172, in B6H yield.  [c.54]

The two extracts were combined and washed six times with 2 N HCl. The light petroleum solutions were dried over magnesium sulfate, then poured into a 1-1 round-bottomed flask, which was equipped for vacuum distillation with a 40-cm Vigreux column, condenser and receiver, cooled at -75°C (see Fig. 5). A tube filled with KOH pellets was placed between the receiver and the water pump. The apparatus was evacuated (10-20 mmHg) and the flask was gradually heated until the light petroleum began to pass over. The distillate was heated under reflux under nitrogen for 20 min (note 2), and was subsequently distilled in a partial vacuum. CH3C C-CH2CeCH, b.p. aa. 55°C/100 mmHg, n 1.4474, was obtained in 74"7 yield.  [c.72]

To a vigorously stirred suspension of 2 mol of lithium amide in 2 1 of liquid atimonia (see II, Exp. 11) was added in 15 min 1 mol of propargyl alcohol (commercial product, distilled in a partial vacuum before use). Subsequently, 1 mol of butyl bromide was added dropwise in 75 min. After an additional 1.5 h, stirring was stopped and the ammonia was allovied to evaporate. To the solid residue were added 500 ml of ice-water. After the solid mass had dissolved, six extractions with diethyl ether were performed. The (unwashed) combined extracts were dried over magnesium sulfate and then concentrated in a water-pump vacuum. Distillation of the residue through a 40-cm Vigreux column afforded 2-heptyn-l-ol, b.p.  [c.77]

A solution of 0.10 mol of 1,6-dichloro-2,4-hexadiyne (VlII-2, Exp. 9) in 150 ml of dry THE was cooled to -90°C and a Solution of 0.35 mol of KO-tcrt.-CgHg (see Chapter IV, Exp. 4, note 2) in 120 ml of THE was added in about 15 min with vigorous stirring. The reaction was very exothermic and efficient cooling in a liquid nitrogen bath was necessary to keep the temperature between -90 and -70°C (note 1). After the addition, the mixture was stirred for an additional 20 min at -65°C. High-boiling light petroleum (b.p. > 190°C) (150 ml) was then added to the dark mixture, followed by 200 ml of 2 N MCI. The layers were separated (note 2) as Soon as possible, taking care that their temperature remained between -5 and -10 C. The aqueous layer was extracted twice with 30-ml portions of light petroleum. The combined light petroleum solutions were washed ten times with 150-ml portions of 2 N HCl (cooled at -10°C) in order to remove the THE and tert.-CgHgOH, and were subsequently dried by swirling for a few minutes with a small amount of magnesium sulfate. The brown extract was decanted from the magnesium sulfate and transferred into a 1-1 round-bottomed flask. The flask was equipped for vacuum distillation  [c.136]

A solution of phenylmagnesium bromide, prepared in the usual way [see Chapter II, Exp. 5) from 0.35 mol of bromobenzene, a 100% excess of magnesium and 300 ml of diethyl ether (note 1), was cooled to 0 C (internal temperature). Copper(I) bromide (1 g, note 2) v/as added and 0.20 mol of methyl propargyl ether (VIlI-6, Exp. 7), dissolved in 100 ml of dry diethyl ether, was added in 10 min. The temperature of the mixture was kept between 0 and 5°C. After the addition, stirring was continued for 20 min at 5-10°C, a dark slurry being formed. Working up was carried out by slow addition of 200 ml of an aqueous solution of 3 g of KCN and 30 g of ammonium chloride to the vigorously stirred mixture. During this addition the flask was cooled in ice-water. After separation of the layers the aqueous layer was extracted with diethyl ether and the combined ethereal solutions were dried over magnesium sulfate and concentrated in a water-pump vacuum. Distillation  [c.159]

A suspension of sodium amide in 500 ml of anhydrous liquid artmonia was prepared from 18 g of sodium (see Chapter II, Exp. 11). To the suspension was added in 10 min with swirling a mixture of 0.30 mol of 1-chloro-l-ethynylcyclohexane (see VIII-2, Exp. 27) and 50 ml of diethyl ether. The reaction was very vigorous and a thick suspension was formed. The greater part of the ammonia was evaporated by placing the flask in a water bath at 50°C. After addition of 500 ml of ice-water the product was extracted three times with diethyl ether. The ethereal extracts were dried over anhydrous KjCOj and subsequently concentrated in a water-pum vacuum. Distillation of the residue afforded the amine, b.p. 54°C/15 mmHg, n 1.4345, in 87% yield.  [c.230]

A steel reaction vessel is partly filled with soHd magnesium, sealed, and flushed with helium or argon. The reactor is placed in a furnace and heated to melt the magnesium. Pure Hquid titanium tetrachloride is slowly fed to the vessel, where it vapori2es and is reduced by molten magnesium. The reaction (eq. 30) is exothermic and proceeds to completion. Some of the Hquid magnesium chloride is drained, and the vessel is cooled to room temperature. The reaction mass, interlocking crystals of metallic titanium, magnesium chloride, and some magnesium metal, is removed by boring. The magnesium chloride and the magnesium are separated from the titanium by vacuum distillation or by leaching with dilute acid. About 700—1400 kg of titanium is produced in one batch. This process is summari2ed in Figure 4 (see Titaniumand titanium alloys).  [c.168]

Principal U.S. producers obtain their cmde naphthalene product by fractional distillation of the tar acid-free chemical oil. This distillation may be accomphshed in either a batch or continuous fashion. One such method for the continuous recovery of naphthalene by distillation is shown in Figure 1. The tar acid-free chemical oil is charged to the system where most of the low boiling components, eg, benzene, xylene, and toluene, are removed in the light-solvent column. The chemical oil next is fed to the solvent column, which is operated under vacuum, where a product containing the prenaphthalene components is taken overhead. This product, which is called coal-tar naphtha or cmde heavy solvent, typically has a boiling range of ca 130—200°C and is used as a general solvent and as a feedstock for hydrocarbon-resin manufacture because of its high content of resinifiables, eg, indene and coumarone (see Hydrocarbon resins). The naphthalene-rich bottoms from the solvent column then are fed to the naphthalene column where a naphthalene product (95% naphthalene) is produced. The naphthalene column is operated at near atmospheric pressure to avoid difficulties which are inherent to vacuum distillation of this product, eg, naphthalene-filled vacuum jets and lines. A side stream which is rich in methylnaphthalenes may be taken near the bottom of the naphthalene column.  [c.484]

Other components in the feed gas may react with and degrade the amine solution. Many of these latter reactions can be reversed by appHcation of heat, as in a reclaimer. Some reaction products cannot be reclaimed, however. Thus to keep the concentration of these materials at an acceptable level, the solution must be purged and fresh amine added periodically. The principal sources of degradation products are the reactions with carbon dioxide, carbonyl sulfide, and carbon disulfide. In refineries, sour gas streams from vacuum distillation or from fluidized catalytic cracking (FCC) units can contain oxygen or sulfur dioxide which form heat-stable salts with the amine solution (see Fluidization Petroleum).  [c.211]

Coumarone—Indene Kesins. These should be called polyindene resins (17) (see Hydrocarbon resins). They are derived from a close-cut fraction of a coke-oven naphtha free of tar acids and bases. This feedstock, distilling between 178 and 190°C and containing a minimum of 30% indene, is warmed to 35°C and polymeri2ed by a dding 0.7—0.8% of the phenol or acetic acid complex of boron trifluoride as catalyst. With the phenol complex, tar acids need not be completely removed and the yield is better. The reaction is exothermic and the temperature is kept below 120°C. When the reaction is complete, the catalyst is decomposed by using a hot concentrated solution of sodium carbonate. Unreacted naphtha is removed, first with Hve steam and then by vacuum distillation to leave an amber-colored resin. It is poured into trays, allowed to cool, and broken up for sale.  [c.339]

In the 1990s, guaiacol is synthesized from catechol, which is prepared by acid-catalyzed hydroxylation of phenol with hydrogen peroxide (see Hydroquinone, resorcinol, and catechol). GlyoxyHc acid is obtained as a by-product in the synthesis of glyoxal from acetaldehyde (qv), and it can also be produced by oxidation of glyoxal with nitric acid. Condensation of guaiacol with glyoxyHc acid proceeds smoothly in alkaline media. Cmde vanillin is obtained by acidification and simultaneous decarboxylation of the 4-hydroxy-3-methoxyphenyl glyoxyHc acid solution. Commercial grades are obtained by vacuum distillation and subsequent recrystaUization.  [c.396]

Toray. The photonitrosation of cyclohexane or PNC process results in the direct conversion of cyclohexane to cyclohexanone oxime hydrochloride by reaction with nitrosyl chloride in the presence of uv light (15) (see Photochemical technology). Beckmann rearrangement of the cyclohexanone oxime hydrochloride in oleum results in the evolution of HCl, which is recycled to form NOCl by reaction with nitrosylsulfuric acid. The latter is produced by conventional absorption of NO from ammonia oxidation in oleum. Neutralization of the rearrangement mass with ammonia yields 1.7 kg ammonium sulfate per kilogram of caprolactam. Purification is by vacuum distillation. The novel chemistry is as follows  [c.430]

Molecular distillation occurs where the vapor path is unobstmcted and the condenser is separated from the evaporator by a distance less than the mean-free path of the evaporating molecules (86). This specialized branch of distillation is carried out at extremely low pressures ranging from 13—130 mPa (0.1—1.0 p.m Hg) (see Vacuum technology). Molecular distillation is confined to appHcations where it is necessary to minimize component degradation by distilling at the lowest possible temperatures. Commercial usage includes the distillation of vitamins (qv) and fatty acid dimers (see Dimeracids).  [c.174]


See pages that mention the term Vacuum distillation, see Distillation : [c.36]    [c.100]    [c.110]    [c.114]    [c.131]    [c.224]    [c.56]    [c.101]    [c.193]    [c.209]    [c.182]   
Textbook on organic chemistry (1974) -- [ c.0 ]