Poly hydroxy alcohols

These compds may be modified by monocar-boxy lie acids or poly hydroxy alcohols. This definition includes the polycarbonates (qv), which are a well-defined segment of the general class of polyesters. Unsaturated polyesters, which are produced when any of the reactants contain non-aromatic unsaturation, can be cross-linked or copolymerized with an un-saturated copolymerizable monomer. The formulas and properties of the class polyester are as varied and extensive as the reactants themselves. For specific information on the various sub-classes and sub-sub classes, the following refs should be consulted 9, 10, II, 16a, 17,18,... 

Polybasic carboxylic hydroxy and amino acid aided synthetic routes directed towards obtaining mixed inorganic materials, especially for battery and fuel cell applications, are overviewed. It has been shown that, in spite of enormous number of papers on the subject, significant efforts should be undertaken in order to understand the basic principles of these routes. Possible influence of the structure of reactants employed in the process (acids, poly hydroxy alcohols, metal salts) is put forward, and some directions of future work in the field are outlined. 

Dissolution of metal salts in the aqueous solution of polybasic hydroxy (or amino) carboxylic acids (and poly hydroxy alcohols) ... 

Role of Polybasic Carboxylic Hydroxy (amino) Acids and Poly Hydroxy Alcohols... 

Furthermore, the role of a poly hydroxy alcohol, like ethylene glycol, seems ambiguous. As mentioned above, it is believed that the presence of ethylene glycol favours esterification of chelates. IR and NMR studies performed in [7] do not present solid proofs of such a belief. Synthetic routines with and without alcohols look the same, and the absence of alcohol seem not to influence the properties of precursors and final products. Some evidence exists enabling one to consider the esterification idea liable to more than one interpretation it has been reported in [4] that the presence of ethylene glycol does not influence the morphology of oxides. 

Accounting for these facts one should not be surprised coming across entirely different recommendations regarding the metal-acid-ethylene glycol ratio, which varies from 1-1.88-1.25 [5] or 1-4-1 [8] to 1-4.25-17.5 [7]. It is even sometimes noticed that a carboxylic acid and a poly hydroxy alcohol simply play the role of a fuel to bum a precursor and to form target oxides [16]. To shed some light on the aforementioned problems, the following steps could be of some help. 

As far as the role of poly hydroxy alcohols is concerned, comparative studies of products obtained with and without their addition should be made. The use of homologous alcohols (like low cost substituted glycols employed as components of brake liquids, and glycerol) could be helpful if such role would be found significant. 

Comparative studies of products obtained with and without addition of poly hydroxy alcohols should be made, so as to determine their role in the process ... 

In such cases, with the halogen and hydroxyl linked to different carbon atoms, stable compounds result. As direct action of halogens oxidizes the alcohol to aldehyde or ketone, this new kind of halogen-alcohol must be prepared by a different reaction. When poly-hydroxy alcohols react with halogen acids, e.g.j hydrochloric acid, HCI, or with phos-... 

From the higher poly-hydroxy alcohols similar halogen-alcohols are obtained, which are known, also, as halogen-hydrines, e.g. ... 

When poly-hydroxy alcohols are oxidized the first product is a compound in which one of the alcohol groups has been oxidized either to aldehyde or to ketone depending on whether the alcohol group is primary or secondary. 

Aldehyde Alcohols.—From the simplest poly-hydroxy alcohol glycol or ethandiol, the only product of this kind that is possible is an aldehyde-alcohol known as glycolic aldehyde. 

Ketone Alcohols.—From the higher poly-hydroxy alcohols however, which contain both primary and secondary alcohol groups we obtain both aldehyde alcohols and ketone alcohols. Glycerol or propantriol thus yields the following ... 

II. The introduction of the carboxyl groups or of some group yielding carboxyl, e.g., the cyanogen group, (—CN), into mono-hydroxy or poly-hydroxy alcohols. These will be analogous to the reactions used for the synthesis of acids. 

From Poly-hydroxy Alcohols.—4. Poly-hydroxy alcohols by oxidation, yield poly-hydroxy acids. In this case, of course, only primary alcohol groups, ( —CH2OH), can yield carboxyl and these groups must, necessarily, be at the end of the carbon chain. The oxidation must be mild so that only one alcoholic group shall be affected. 

As each poly-hydroxy alcohol must have as many carbon groups as it has hydroxyls, so also, a poly-basic acid must have at least as many carbon groups as it has carboxyls and the simplest di-basic acid must be derived from the two carbon hydrocarbon. 

Oxidation Products of Poly-hydroxy Alcohols.—In our study of the mixed poly-substitution products we considered the mixed alcohol-aldehyde and alcohol-ketone compounds and showed that they are intermediate oxidation products between poly-hydroxy alcohols and poly-basic acids (p. 228). To illustrate, when glycerol, tri-hydroxy propane, is oxidized the following products are obtained. 

Alcohol Compounds.—That the carbohydrates are, in fact, alcohol compounds is shown, both by their relation to poly-hydroxy alcohols and by their reactions. Carbohydrates possess alcohol characters in that they undergo distinctly alcoholic reactions. Like all alcohols they react with acetyl chloride or acetic anhydride. In.practice the latter reagent is used. They form acetyl derivatives, or esters, just as ethyl alcohol does. 

Number of Hydroxyl Groups.—In this way it has been shown that in the simple carbohydrates the number of hydroxyl groups is one less than the number of carbon atoms. As more than one hydroxyl group is not usually linked to one carbon the indication is that each carbon atom but one has one hydroxyl group linked to it. That the remaining carbon atom is in a carbonyl grouping was first established by Kiliani, who showed that in water solution the carbohydrates are aldehyde or ketone compounds as well as poly-hydroxy alcohols. 

S mthesis.—The carbohydrates have been prepared synthetically by oxidizing the poly-hydroxy alcohols. We have recently spoken of the mixed alcohol and aldehyde or mixed alcohol and ketone compounds which are formed by the oxidation of the tri-hydroxy alcohol glycerol. We have, also, just stated that the carbohydrates have been proven to be mixed poly-hydroxy alcohols and aldehydes or ketones. The compound just referred to, as produced by the oxidation of glycerol, is the simplest compound which has the character of a true sugar. Its composition is in accordance with the first of the general formulas, viz., CsHeOs or C H2nOn, and from the number of carbon atoms present it would be termed a triose. The oxidation of glycerol results in a mixture of two compounds, viz., an aldehyde alcohol and a ketone alcohol. 

Reduction.—By reduction they are converted into the poly-hydroxy alcohols containing the same number of carbon atoms. 

I. By the formation of acetyl derivatives and by the reduction to normal hydrocarbons containing the same number of carbon atoms, passing through the poly-hydroxy alcohols of the same number of carbons, carbohydrates are poly-hydroxy alcohols in which each carbon but one has one and only one hydroxyl group linked to it. 

By the three preceding reactions and by the formation of carbohydrates by the oxidation of poly-hydroxy alcohols, carbohydrates are poly-hydroxy alcohols in which one alcohol group is oxidized to aldehyde (primary alcohol group at the end of the chain), or to ketone (secondary alcohol group). 

Carbohydrates are aldehyde or ketone oxidation products of normal poly-hydroxy alcohols of the same number of carbon atoms, in which one carbon group only is oxidized to aldehyde or ketone, the aldehyde group being the end carbon group and the ketone group being next to the end. 

Gun Cotton.—As nitric acid esters of poly-hydroxy alcohols, the two important explosives nitro glycerol and gun cotton are exactly analogous not only in character but also in the fact that each is the... 

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