Alcohols branched-chain, solubility

The solubility of several salts of alkyl esters of a-sulfopalmitic acid and a-sulfostearic acid was measured by Stirton et al. [30]. The aqueous solubility of the a-sulfopalmitates is better than the solubility of the a-sulfostearates and it also increases with increasing molecular weight of the alcohol. The same dependency is found in organic solvents, such as chloroform ethanol, petroleum ether diethyl ether, and mineral oil. They also showed that esters of secondary and branched chain alcohols are more soluble than esters of normal primary alcohols. 

The nickel oxide electrode is generally useful for the oxidation of alkanols in a basic electrolyte (Tables 8.3 and 8.4). Reactions are generally carrried out in an undivided cell at constant current and with a stainless steel cathode. Water-soluble primary alcohols give the carboxylic acid in good yields. Water insoluble alcohols are oxidised to the carboxylic acid as an emulsion. Short chain primary alcohols are effectively oxidised at room temperature whereas around 70 is required for the oxidation of long chain or branched chain primary alcohols. The oxidation of secondary alcohols to ketones is carried out in 50 % tert-butanol as solvent [59], y-Lactones, such as 10, can be oxidised to the ketoacid in aqueous sodium hydroxide [59]. 

Branched chain surfactants are an important direction for finding surfactants that have greater solubility at low temperatures. An alcohol sulphate based on a branched Cl 7 alcohol was developed by Shell Chemical and patented for laundry use by Procter Gamble. This material is in use today and offers an important avenue to the future of detergent materials. 

Supported aqueous-phase catalysts can also be used to advantage. These supported catalysts have a thin aqueous film adhering to silica gel that contains the water-soluble complex (131). These catalysts are particularly useful for the hydroformylation of substrates such as oleyl alcohol (132). Since these catalytic reactions occur at the phase boundary, characteristics such as the water content can cause changes both in the reactivity and in the linear branched chain ratio of the product aldehyde. 

Interactions between nonpolar groups and water were discussed above, where the importance of both size and shape was indicated. Chain branching of hydrophobic groups influences aqueous solubility, as shown by the solubilities of a series of straight and branched-chain alcohols in Table 5.2. 

After colloidal silica particles of definite and uniform size became available, it was possible to esterify the surface and show that the product indeed consists of a monomolecular layer of oriented butoxy replacing some of the hydroxyl groups on the silica surface so that the outer surface of the particle is essentially a layer of hydrocarbon groups. This hydrocarbon surface may be aliphatic in nature, as when an alcohol such as butyl is employed, or aromatic, as when benzyl is used. The nature of the hydrocarbon surface affects the solubility and dispersibility of the particles. Thus when silica particles 17 nm in diameter are esterified with benzyl alcohol, a dry powder product is obtained that dissolves to a clear solution in benzene, but is not soluble in an aliphatic solvent such as kerosene. On the other hand, when the same silica is esterified with an aliphatic branched-chain octadecyl alcohol, the powder dissolves readily in kerosene (442). 

Branched-chain compounds have greater water solubility than their straigjit-chain counterparts, as illustrated in Table 5.2 with a series of alcohols. 

Amino acid metabolism generates aromatic, aliphatic, and branched chain alcohols, acids, carbonyls, and esters that are important to the flavor of fruit. Yu et al. [20-22] were amongst the earliest researchers to demonstrate that valine, leucine, alanine, and aspartic acid can be converted to short chain carbonyls by tomato extracts. The enzymes involved in these transformations were found to be located in different sites in the tomato. The soluble tomato fraction isolated via centrifugation acted on leucine while the mitochondrial fraction metabolized both alanine and aspartic acid. The... 

Monoesters based on linear fatty alcohols are only partially water-soluble and hardly dispersible. Those based on fatty alcohol ethoxylates exhibit much better solubility. Dialkyl esters based on alcohols wifii le than nine carbons, preferably five to eight carbons, as well as those based on fatty acid ethanol amides are water soluble and, therefore, are generally preferred. It is worth noting that solubility can still be increased by using branched chains. 

Curdlan is a microbial polysaccharide that occurs naturally as a linear (triple-helix) polysaccharide composed of 1,3-P-hnked D-glucose units, produced by a strain of Mcaligenes faecalis (Figure 2.38). It is a neutral, bacterial polysaccharide without branched chains. It is insoluble in water and alcohol but soluble in alkaline solution and dimethyl sulfoxide (DMSO) [274-276]. It occurs as a tasteless powder, stable in dry state. It was reported as a support matrix for enzyme immobilization, through activation with epichlorohydrin that can be covalently linked to the available amino, hydroxyl, and suHhydryl enzyme groups [277]. It has the specific character to form an irreversible gel by heating of a water suspension [278]. Its water-insoluble nature helps to improve a material s water barrier capabihty, and its solubility in... 

However, this equation should be used with caution. Shiao and co-workers (1998) reported that the BSO equation failed if the microemulsion contained components with branched alkyl chains, as these decreased the packing order of the hydrocarbons in the interface compared to linear alkyl chains. Garti and co-workers (1995, 2000a) showed that the BSO equation was valid for non-ionic surfactants in five-component microemulsions only when the surfactant (alcohol) exhibited limited solubility in both the aqueous and oil phases. 

The lower members of other homologous series of oxygen compounds— the acids, aldehydes, ketones, anhydrides, ethers and esters—have approximately the same limits of solubility as the alcohols and substitution and branching of the carbon chain has a similar influence. For the amines (primary, secondary and tertiary), the limit of solubility is about C whilst for the amides and nitriles it is about C4. 

Because the thermal separation of products has been substituted by a liquid-liquid separation, the two phase technology should be best suited for hydroformylation of longer chain olefins. But with rising chain length of the olefins the solubility in the aqueous catalyst phase drops dramatically and as a consequence the reaction rate. Only the hydroformylation of 1-butene proceeds with bearable space-time yield. This is applied on a small scale for production of valeraldehyde starting from raffinate II. Because the sulfonated triphenylphosphane/rhodium catalyst exhibits only slow isomerization and virtually no hydroformylation of internal double bonds, only 1-butene is converted. The remaining raffinate III, with some unconverted 1-butene and the unconverted 2-butene, is used in a subsequent hydroformy-lation/hydrogenation for production of technical amylalcohol, a mixture of linear and branched C5-alcohols. 

Ru(II)-TPPTS to the corresponding unsaturated alcohols in biphasic mode. If one compares the reaction times until full conversion, it becomes clear that the reaction rate correlates with the solubility of the substrate in the aqueous phase, as expected. The latter decreases with increasing chain length or branching of the chain at the C3-atom. In contrast to heterogeneously catalysed hydrogenations of o , d-unsaturated aldehydes, the steric hindrance of substituents at the C3-atom only plays a minor role in the coordination mode of the substrate at the metal centre, since selectivity differences from croton-aldehyde to citral are marginal. 

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