Preparation of Alcohols and Ethers

The monoalkyl ethers with R = CHj, CjHj and C4H, , known respectively as methyl ceUoaolve, ceUosolve and hutyl cellosolve, are of great commercial value, particularly as solvents, since they combine the properties of alcohols and ethers and are miscible with water. Equally important compounds are the carbitols (monoalkyl ethers of diethyleneglycol) prepared by the action of ethylene oxide upon the monoethers of ethylene glycol ... 

The hydrochloride addition salt of the above reaction product was prepared in customary fashion, that is, by reaction with hydrochloric acid, followed by fractional crystallization from a mixture of alcohol and ether. The two possible racemic forms were obtained thereby. The difficultly soluble racemate had a melting point of 169° to 170°C and the more readily soluble racemate had a boiling point of 145° to 148°C. 

The unsoluble fluorophosphates can be prepared from the sodium salt by reaction with heavy metal nitrates, whereas the watersoluble salts are appropriately prepared by the reaction of the sligthly soluble AgjPOjF with heavy metal chlorides (24). Acid salts M H[P03F] with = Na, K, NH4 result from fractional precipitation by addition of alcohol and ether to the aqueous solution of the free acid (17). Further methods for the synthesis of fluorophosphates are given by Eqs. (12) and (13), which lead to dimethylin fluorophosphate (32) and to tin (II) difluorophosphate (55) ... 

Chromium triphenyl perchlorate, (C6H5)3CrC104, is prepared by the fractional precipitation of a solution of chromium triphenyl hydroxide with dilute perchloric acid. The salt is microcrystalline it is best preserved under a mixture of alcohol and ether in an ice-chest in the dry state it is more labile and explosive than the corresponding tetraphenyl compound. 

T. Curtius and A. Darapsky prepared a basic salt, lanthanum hydroxyazide, La(0H)(N3)2l H20, by boiling a soln. of lanthanum nitrate and sodium azide. The white, slimy mass of basic lanthanum azide is obtained by evaporating the mixed soln. in vacuo, or by treatment of the soln. with a mixture of alcohol and ether. They also made rose-coloured didymium hydroxyazide, Dy(OH)(N3)2, by evaporating a soln. of didymium carbonate in hydrazoic acid. Freshly precipitated yttrium hydroxide dissolves in hydrazoic acid, forming a soluble yttrium hydroxyazide boiling a soln. of yttrium sulphate and sodium azide gives a precipitate of yttrium hydroxide. L. M. Dennis found that zirconium hydroxide is precipitated when a soln. of zirconium salt is treated with potassium azide. 

When some straight and branched-chain aliphatic alcohols, such as n-propanol, n-butanol and isopropanol, are subjected to high temperatures, dehydrogenation products predominate over dehydration (51). Presumably the eliminations take place via a six-membered transition state and are catalyzed by hydrogen halides in the homogeneous phase (52) to produce olefins. On the other hand, gas phase dehydration over solid catalysts is a valuable process for the preparation of olefins and ethers. 

Symmetrical aliphatic ethers (C -Ci,) are prepared by the removal of water from alcohols under acidic conditions. Thus, in the preparation of diisoamyl ether, the alcohol is heated with concentrated sulfuric acid or p-toluenesulfonyl chloride in a flask equipp>ed with a condenser and a water sep>arator. The top layer of alcohol and ether is returned to the reaction flask until water no longer separates. Any alcohol remaining in the ether is converted to the higher-boiling triisoamyl borate, and the ether is purified by fractional distillation. Several suitable water separators have been described. High reaction temperatures must be avoided to prevent the formation of unsaturated hydrocarbons (cf. method 19). 

Isohypsic reactions of alkenes, like electrophilic additions of H2O or HX, represent a conventional pathway for the preparation of alcohols and alkyl halides from alkenes. The scope of their application was originally limited as unsymmetrical alkenes (e.g. 125) gave product mixtures composed of both Markovnikov (M) adducts and anti-Markovnikov (aM) adducts. As was already mentioned above (see Scheme 2.10), an efficient and general method for the conversion of alkenes into alcohols or ethers 126 (Scheme 2.47), with a nearly complete M selectivity, was elaborated using mercury salts as electrophiles in conjunction with the reduction of the formed adducts. It is also... 

Bases, Neutral Salts.— As a base it forms salts, in which form the diazo compound is obtained by diazotization, and which though also unstable has been isolated in small quantities and the composition and properties determined. Of the three salts, the sulphate, chloride and nitrate, the first is the most stable and the last is the least stable. They are colorless crystalline neutral compounds soluble in water, difficultly soluble in alcohol and insoluble in ether. After being prepared by the ordinary diazo reaction, with sodium nitrite in cold acid water solution, they may be precipitated in crystalline form by the addition of alcohol and ether. If the diazotization is effected in alcohol solution by means of amyl nitrite or ethyl nitrite the crystals of the diazonium salt separate at once. These salts of diazo benzene all show true salt characteristics, e.g., they lower the freezing point of solutions. The diazo radical, (CeHs—N2—) is thus basic toward strong acids, and the hydroxide, the non-isolated hypothetical diazo benzene, CeHs—N2—OH, is the free base. It may be considered as the simplest aromatic diazo compound and the mother substance of all other members of the class. 

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