Alcohols and water

Iodine as such finds few uses but a solution in alcohol and water, also containing potassium iodide ( tincture of iodine was commonly used as an antiseptic for cuts and wounds, but had rather an irritant action. Iodoform (triiodomethane), CHI3, is also an antiseptic, but newer compounds of iodine are now in use. Silver iodide, like silver bromide, is extensively used in the photographic industry. 

If the substance is found to be far too soluble in one solvent and much too insoluble in another solvent to allow of satisfactory recrystallisation, mixed solvents or solvent pairs may frequently be used with excellent results. The two solvents must, of course, be completely miscible. Recrystallisation from mixed solvents is carried out near the boiling point of the solvent. The compound is dissolved in the solvent in which it is very soluble, and the hot solvent, in which the substance is only sparingly soluble, is added cautiously until a slight turbidity is produced. The turbidity is then just cleared by the addition of a small quantity of the first solvent and the mixture is allowed to cool to room temperature crystals will separate. Pairs of liquids which may be used include alcohol and water alcohol and benzene benzene and petroleum ether acetone and petroleum ether glacial acetic acid and water. 

Other mixtures which may be employed are carbon tetrachloride (b.p. 77°) and toluene (b.p. 110-111°) chloroform (b.p. 61°) and toluene methyl alcohol (b.p. 65°) and water (b.p. 100°). The last example is of interest because almost pure methyl alcohol may be isolated no constant boiling point mixture (or azeotropic mixture) is formed (compare ethyl alcohol and water, Sections 1,4 and 1,5). Attention is directed to the poisonous character of methyl alcohol the vapour should therefore not be inhaled. 

Method 2 (Alkaline hydrolysis). Use a solution of 15 g. of p-bromo-acetanihde in 30 ml. of boiling ethyl alcohol, and add a solution of 7 5 g. of potassium hydroxide in 10 ml. of water. Reflux for 40 minutes, dilute with 120 ml. of water, and distil vmtil 75 ml. of distillate (alcohol and water) are collected pour the residue into 150 ml, of cold water. 

Add 40 ml. of ethyl alcohol to 21 -5 g. of 70 per cent, ethylenediamine solution (0 -25 mol) dissolve 36 -5 g. of adipic acid (0 -25 mol) in 50 ml. of a 6 1 mixture of ethyl alcohol and water. Mix the two solutions, stir and cool. Filter off the resulting salt and recrystalliae it from 60 ml. of a 6 1 ethyl alcohol - water mixture, and dry the salt in the air. Heat the salt in an atmosphere of oxygen-free nitrogen or of carbon dioxide in an oil bath until it melts (ca. 160°) the product will sohdify after a short time. Reduce the pressure to 15 mm. of mercury or less and raise the temperature of the oil bath until the product remelts (about 290°) and continue the heating for 4r-5 hours. Upon coohng, a nylon type polymer is obtained. 

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. 

Other sulfur compounds such as thiourea, ammonium dithiocarbamate, or hydrogen sulfide also lead to 2-mercaptothiazoles. Thus thiourea has been used in the syntheses of 4,5-dimethyl (369) and 4-aryl-2-mercapto-thiazoles (Table 11-30) (519). The reactions were carried out by condensing the ia -thiocyanatoketones with thiourea in alcohol and water acidified with hydrochloric acid. By this procedure, 4-aryl-2-mercaptothiazoles were obtained in yields of 40 to 80% with bis-(4-aryl-2-thiazolyl) sulfides as by-products (519). These latter products (194) have also been observed as a result of the action of thiourea on 2-chloro-4-arylthiazole under the same experimental conditions. They can be separated from 2-mercaptothiazoles because of their different degrees of solubility in sodium hydroxide solution at 5%. In this medium bis-(4-phenyl-2-thiazolyl)sulfide is... 

Reactions were carried out by condensing a-thiocyanatokeiones with thiourea in alcohol and water acidified with hydrochloric acid. 

Solubility in Water Alkyl halides and alcohols differ markedly from one another m their solubility m water All alkyl halides are insoluble m water but low molecular weight alcohols (methyl ethyl n propyl and isopropyl) are soluble m water m all pro portions Their ability to participate m mtermolecular hydrogen bonding not only affects the boiling points of alcohols but also enhances their water solubility Hydrogen bonded networks of the type shown m Figure 4 5m which alcohol and water molecules asso ciate with one another replace the alcohol-alcohol and water-water hydrogen bonded networks present m the pure substances... 

The reaction is of the 8 2 type and works best with primary and secondary alkyl halides Elimination is the only reaction observed with tertiary alkyl halides Aryl and vinyl halides do not react Dimethyl sulfoxide is the preferred solvent for this reaction but alcohols and water-alcohol mixtures have also been used... 

The mixture is cooled and noncondensable gases are scmbbed with water. Some of the resultant gas stream, mainly hydrogen, may be recycled to control catalyst fouhng. The Hquids are fractionally distilled, taking acetone overhead and a mixture of isopropyl alcohol and water as bottoms. A caustic treatment maybe used to remove minor aldehyde contaminants prior to this distillation (29). In another fractionating column, the aqueous isopropyl alcohol is concentrated to about 88% for recycle to the reactor. 

Acryflc acid, alcohol, and the catalyst, eg, sulfuric acid, together with the recycle streams are fed to the glass-lined ester reactor fitted with an external reboiler and a distillation column. Acrylate ester, excess alcohol, and water of esterification are taken overhead from the distillation column. The process is operated to give only traces of acryflc acid in the distillate. The bulk of the organic distillate is sent to the wash column for removal of alcohol and acryflc acid a portion is returned to the top of the distillation column. If required, some base may be added during the washing operation to remove traces of acryflc acid. 

Ammonium lactate [34302-65-3] ia coaceatrated aqueous solutioas has beea coaverted to ammonia and the ester by alcoholysis at temperatures ranging from 100—200°C usiag a variety of alcohols and water entrainers, such as toluene. Ester yields ranging from 50—80% were obtained. This method has also been suggested as a recovery and purification method from impure solutions of lactate (29). However, a considerable amount of the lactate is not converted to the recoverable ester and is lost as lactamide (6). 

The principal impurity in potassium metal is sodium. Potassium s purity can be accurately deterrnined by a melting point test (Fig. 2) or atomic absorption if necessary after quenching with alcohol and water. Traces of nonmetallic impurities such as oxygen, carbon, and hydrogen can be deterrnined by various chemical and physical methods (7,8). 

The mechanism of the alkylation reaction is similar to curing. The methylo1 group becomes protonated and dissociates to form a carbonium ion intermediate which may react with alcohol to produce an alkoxymethyl group or with water to revert to the starting material. The amount of water in the reaction mixture should be kept to a minimum since the relative amounts of alcohol and water determine the final equiHbrium. 

The esters of sahcyhc acid account for an increasing fraction of the sahcyhc acid produced, about 15% in the 1990s. Typically, the esters are commercially produced by esterification of sahcyhc acid with the appropriate alcohol using a strong mineral acid such as sulfuric as a catalyst. To complete the esterification, the excess alcohol and water are distilled away and recovered. The cmde product is further purified, generally by distillation. For the manufacture of higher esters of sahcyhc acid, transestetification of methyl sahcylate with the appropriate alcohol is the usual route of choice. However, another reaction method uses sodium sahcylate and the corresponding alkyl hahde to form the desired ester. 

The addition of TYZOR AA to larger quantities of water results in precipitation of the polytitanaoxane as a yellow soHd, which can be isolated and dried (92). The precipitation of this soHd can be prevented by diluting the TYZOR AA with an equal volume of 10% aqueous acetic acid and then 13 times the amount of a 1 1 mixture of isopropyl alcohol and water (93). 

The copolymers are insoluble in water unless they are neutralized to some extent with base. They are soluble, however, in various ratios of alcohol and water, suggesting appHcations where deUvery from hydroalcohoHc solutions (149) but subsequent insolubiUty in water is desired, such as in low volatile organic compound (VOC) hair-fixative formulations or tablet coatings. Unneutralized, their Ts are higher than expected, indicating interchain hydrogen bonding (150). 

Alcoholic Solutions or Extracts. AlcohoHc extracts are prepared by dissolving the flavor-beating body ia a solution of alcohol and water. They may require filtration usiag filter aids to remove any iasoluble precipitates or oils that may form. AlcohoHc extracts are clear solutions and are used ia beverages that do not require a haze or cloudiness. 

The monoamides can be cycli2ed to form imida2olines. This can be done without isolation of the monoamide by a variety of techniques including distilling the alcohol and water away as formed (33), heating under vacuum (34), heating in a hydrocarbon solvent under vacuum (35), or heating in the... 

Table 6. Respective Volumes of Alcohol and Water and Specific Gravity ...

Variables a andZ are specific constants reported by Tsonopoulos for some alcohols and water (e.g., methanol a = 0.0878, b = 0.0560 and water a = 0.0279, b = 0.0229). Tsonopoulos also gives specific prediction methods for haloalkanes and water pollutants. 

Volatiles composition Methanol and water Xylene and water Alcohol and water Methanol... 

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]. 

Distillation is required to remove aldehyde, alcohol, and water which would react with the Grignard reagent in the next step. a,d-Dibromoethyl ethyl ether is also a lachrymator. 

In a 2-1. flask fitted with a total-reflux, variable-take-off distillation head is placed a solution of 53 g. (0.472 mole) of dihydroresorcinol (Note 1), 2.3 g. of -toluenesulfonic acid monohydrate and 250 ml. of absolute ethanol in 900 ml. of benzene. The mixture is heated to boiling and the azeotrope composed of benzene, alcohol, and water is removed at the rate of 100 ml. per hour. When the temperature of the distilling vapor reaches 78° (Note 2), the distillation is stopped and the residual solution is washed with four 100-ml. portions of 10% aqueous sodium hydroxide which have been saturated with sodium chloride. The resulting organic solution is washed with successive 50-ml. portions of water until the aqueous washings are neutral and then concentrated under reduced pressure. The residual liquid is distilled under reduced pressure. The yield of 3-ethoxy-2-cyclohexenone (Note 3), b.p. 66-68.5°/0.4 mm. or 115-121°/11 mm., Mq 1.5015, is 46.6-49.9 g. (70-75%). 

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