Polyhydric alcohols, preparation

Benzoates. The preparation of benzoates of polyhydric alcohols may be illustrated by reference to glycerol. They are usually crystaUine solids. 

Polyhydric alcohol mercaptoalkanoate esters are prepared by reaction of the appropriate alcohols and thioester using -toluenesulfonic acid catalyst under nitrogen and subsequent heating (16,17). Organotin mercapto esters are similarly produced by reaction of the esters with dibutyltin oxide (18). Pentaerythritol can be oxidized to 2,2-bis(hydroxymethyl)hydracryhc acid [2831-90-5] C H qO, ... 

Bromohydrins can be prepared direcdy from polyhydric alcohols using hydrobromic acid and acetic acid catalyst, followed by distillation of water and acetic acid (21). Reaction conditions must be carehiUy controlled to avoid production of simple acetate esters (22). The raw product is usually a mixture of the mono-, di-and tribromohydrins. 

As a dibasic acid, malic acid forms the usual salts, esters, amides, and acyl chlorides. Monoesters can be prepared easily by refluxing malic acid, an alcohol, and boron trifluoride as a catalyst (9). With polyhydric alcohols and polycarboxyUc aromatic acids, malic acid yields alkyd polyester resins (10) (see Alcohols, polyhydric Alkyd resins). Complete esterification results from the reaction of the diester of maUc acid with an acid chloride, eg, acetyl or stearoyl chloride (11). 

Sulfation andSulfamation. Sulfamic acid can be regarded as an ammonia—SO. complex and has been used thus commercially, always in anhydrous systems. Sulfation of mono-, ie, primary and secondary, alcohols polyhydric alcohols unsaturated alcohols phenols and phenolethylene oxide condensation products has been performed with sulfamic acid (see Sulfonation and sulfation). The best-known appHcation of sulfamic acid for sulfamation is the preparation of sodium cyclohexylsulfamate [139-05-9] which is a synthetic sweetener (see Sweeteners). 

Metal complexes prepared by reacting less than one mole of an alkan olamine with an excess of a polyhydric alcohol, such as polyethylene glycol 200—400 or glycerol, reportedly impart a greater degree of thixotropy to systems containing protective organic coUoids (501). 

Mouthwashes are hydro-alcohoHc preparations in which flavorants, essential oils (see Oils, essential), and other agents are combined to provide long-term breath deodorization. PalatabiHty can be improved by including a polyhydric alcohol such as glycerin or sorbitol (see Alcohols, polyhydric). Occasionally, anionic and nonionic surfactants are used to help solubiHze flavorants and to help remove debris and bacteria from the mouth. 

Transparent dentifrices can be prepared from certain xerogel siUcas through use of high levels of polyhydric alcohols. Clarity depends on matching the refractive indexes of the siUca and the Hquid base. Compositions for Hquid facial cleansers (68), shampoos (69), conditioning shampoos (70), dandmff shampoos (71), surfactant bars (72), toothpastes (73), and mouthwashes (74) have been pubUshed. 

Besides these normal technical products, many other different types of a-sulfo fatty acid esters have been described in the literature. For example, Weil et al. prepared a-sulfopalmitates and stearates with higher alcohols [19] and also monoesters of polyhydric alcohol [39] and of hexitols and sucrose [40] for their special properties. In addition to the sodium salt, Stirton et al. used other cations, such as Li, NH4, K, Mg, and Ca, to study the relationship between the structure and the surfactant properties [30]. 

A polyether-alcohol, prepared by co-condensation of ethylene oxide and propylene oxide with a polyhydric alcohol, was stored at above 100°C and exposed to air via a vent line. After 10-15 h, violent decomposition occurred, rupturing the vessel. It was subsequently found that exothermic oxidation of the product occurred above 100°C, and that at 300°C a rapid exothermic reaction set in, accompanied by vigorous gas evolution. 

This one-step procedure is a convenient and general method for the preparation of carbamates. It is substantially simpler, quicker, and safer than the multistep methods hitherto used for the preparation of carbamates of tertiary alcohols. This procedure is applicable to the preparation of carbamates of primary, secondary, and tertiary alcohols and mercaptans, polyhydric alcohols, acetylenic alcohols, phenols, and oximes. It has also been extended to the preparation of carbamyl derivatives (i.e., ureas) of inert (non-basic) amines.10... 

F5TeO(CH2)2OTeF5, cis-[0(CH2)20]TeF4, and related compounds are formed in reactions of TeF with ethylene glycol and other polyhydric alcohols (69). The alkoxotellurium(VI) fluorides isolated so far are distillable liquids with considerable stability against hydrolysis. Some of these compounds have been prepared more easily by reacting diazoalkanes with pentafluoroorthotelluric acid (174), as in Eq. (11) ... 

It is becoming apparent that wood components, especially lignin, are chemically modified by solvents during wood dissolution, and that the resulting wood tars or pastes become highly reactive. Attempts have therefore been made to prepare effective adhesives, moldable resins and other products from wood after dissolution in phenols or polyhydric alcohols. This review presents recent progress on wood dissolution, and on the preparation of epoxy and phenol resin adhesives from kraft lignin. 

PTOMAINE. A group of highly toxic substances (derivatives of ethers of polyhydric alcohols) resulting from the putrefaction or metabolic decomposition of animal proteins. Examples that have been isolated and prepared synthetically are cadavenne (1,5-diaminopentane), muscarine (hydrox-yethyltrimethylammonium hydroxide), putrescine (telraethylenediamine), and neurine (trimethylvinyl-ammomum hydroxide). 

SAPONIFICATION. A special case of hydrolysis in which an ester is converted into an alcohol and a salt of the appropriate acid by reaction with an alkali. Though the operation has numerous applications throughout the chemical industry, it is noteworthy because some 80% of standard soap is prepared by this method. The esters may be of mono- or polybasic acids and mono- or polyhydric alcohols, the physical conditions under... 

Thermosetting space-network polymers can be prepared through the reaction of polybasic acid anhydrides with polyhydric alcohols. A linear polymer is obtained with a bifunctional anhydride and a bifunctional alcohol, but if either reactant has three or more reactive sites, then formation of a three-dimensional polymer is possible. For example, 2 moles of 1,2,3-propane-triol (glycerol) can react with 3 moles of 1,2-benzenedicarboxylic anhydride (phthalic anhydride) to give a highly cross-linked resin, which usually is called a glyptal ... 

Chromic acid or alkali dichromate and sulphuric acid is employed for the simpler alcohols polyhydric alcohols are usually oxidised with moderately dilute nitric acid if the acid be too concentrated the molecule may be attacked as a whole (cf. Preparation 184). 

For the preparation of derivatives of polyhydric alcohols see under Alcohols and polyhydric alcohols, Section 9.6.4, p. 1241. 

The experimental procedure to be followed depends upon the products of hydrolysis. If the alcohol and aldehyde are both soluble in water, the reaction product is divided into two parts. One portion is used for the characterisation of the aldehyde by the preparation of a suitable derivative (e.g. the 2,4-dinitro-phenylhydrazone, semicarbazone or dimethone, see Aldehydes and ketones, Section 9.6.13, below). The other portion is employed for the preparation of a 3,5-dinitrobenzoate, etc. (see Alcohols and polyhydric alcohols, Section 9.6.4, p. 1241) it is advisable first to concentrate the alcohol by distillation or to attempt to salt out the alcohol by the addition of solid potassium carbonate. If one of the hydrolysis products is insoluble in the reaction mixture, it is separated and characterised. If both the aldehyde and the alcohol are insoluble, they are removed from the aqueous layer separation is generally most simply effected with sodium metabisulphite solution (compare Expt 5.82), but fractional distillation may sometimes be employed. 

They designated these forms ayn, amphi and anti. The writers are aware of only one occasion on which an acetal of a polyhydric alcohol has actually been isolated in isomeric forms of the type under discussion, namely that on which Ness, Hann and Hudson71 obtained two of the four theoretically possible diastereomers of 1,3 5,7-dibenzylidene-D-perseitol. One isomer, having m. p. 153-155° and [a]J° — 58.2° (in pyridine), resulted from the treatment of D-perseitol with benzaldehyde in ethanol at 25°, 50% sulfuric acid being employed as the catalyst. The other, having m. p. 280 2° and [a] ° — 58.1° (in pyridine), was produced when the condensation was carried out at 0° in aqueous ethanol saturated with hydrogen chloride. The former was converted into the latter by recrystallization from a pyridine-alcohol mixture. The corresponding labile and stable forms of l,3 5,7-dibenzylidene-L-perseitol also have been prepared.71 The facility with which the labile form could be converted into its stable isomer in the presence of basic substances may well explain why other workers have failed to isolate isomers of this type. 

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