Inorganic sulphur esters

Fig. 12.5 Determination of carbon-bonded sulphur, ester sulphate and total organic sulphurfrom analyses of total sulphur, hydriodic acid reduction, extractable inorganic sulphate, HCI digestion and Zn-HCI reduction.

The method [97] discussed in section 12.8.1.1 for the determination of sulphur in soils has been applied to lake sediments. Landers [97] also determined organic sulphur (carbon bonded sulphur and ester sulphate) and inorganic sulphur (sulphate and sulphide) in lake sediments. Some results... 

Ester sulphate and carbon bonded sulphur are the major sulphur constituents together with a high Zn-HCl reducible sulphur content, indicating that inorganic sulphur constituents other than sulphates may be important. 

Sulphates. These include sulphuric esters together with any inorganic sulphate (CaSO ). Dunnicliff gives the following method g, of nitrocellulose is heated on a water-bath with 50 c,c. cone, nitric acid until the nitrocellulose has dissolved and brown fumes have ceased. About 1 g. sodium chlorate is added in small quantities and the whole evaporated to dryness. The residue is treated with 20 c-c. of hydrochloric acid and 0 5 sodium chlorate (added in small quantities) and the liquid again evaporated to dryness. This latter treatment is repeated. This converts all sulphuric esters to soluble. sulphate, which may be estimated in the usual way. A blank test is made to allow for sulphate in the reagents. 

In point of fact it has been established by many workers that a nitrocotton freshly produced and washed from acid could contain up to 8% of sulphuric add cellulose esters. Berl and Boltenstem [7] stated in later investigations that sulphuric add always occurred in the stabilized nitrocotton in two forms (a) as an inorganic salt, for the most part CaS04 (b) as sulpho groups chemically combined with cellulose. Their data are given in Table 62. 

Volume 10 is devoted to formation and solvolysis of esters and related reactions, with discussion of the effect of neighbouring groups and biological implications, e.g. enzyme action, where appropriate. The first chapter deals mainly with esters of the inorganic acids of phosphorus and sulphur, Chapter 2 with the formation and solvolysis of esters of organic acids and the final chapter with the solvolysis of related derivatives of carboxylic acids, e.g. halides, amides, anhydrides, cyanides, carbamic acid derivatives. 

The hydroxamic acid test is also given by acid chlorides and some primary aliphatic amides which are readily converted by hydroxylamine hydrochloride into hydroxamic acids. Some esters, mainly of carbonic, carbamic, sulphuric and other inorganic acids, give only a yellow colour. 

In the case of the halogen acids which are binary acids or non-oxygen acids the esters are the same as the alkyl halides, i.e., halogen substitution products of the hydrocarbons. With the oxygen acids, e.g., nitric, sulphuric, etc., the esters are not simple substitution products of hydrocarbons. With these inorganic acids which contain oxygen the acid... 

The salts of the inorganic esters of nonylphenol with phosphoric acid and sulphuric acid are frequently employed in a variety of applications. For example, the dilithio salt of nonylphenylphosphate has been employed as a component of lubricating greases (ref.42). 

Hydrolytic reactions of inorganic esters of sulphur can be illustrated by several typical examples. Monoesters react as follows ... 

Besides the esterases for esters of organic adds, there are esterases for the esters of inorganic acids. A widely distributed group is that of the sulphatases or esterases for esters of sulphuric add. 

Small quantities of inorganic sulphate are found in the body, and sulphuric acid esters of polysaccharides are present notably in the connective tissues. Sulphur also occurs in sulphydryl and disulphide groupings. The sulphydryl group is weakly acidic and can ionize... 

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