Alkylation side chain influence

Sodium LAS synthesized via aluminum chloride catalysis dissolves better than sodium LAS from the hydrogen fluoride route. The main difference is the tetralin content. Dialkyltetralinsulfonates (DATs) function as hydrotropes and this influence can be larger than that of the 2-phenylalkane content. For a homolog (equal alkyl side chains), the higher the DAT content, the lower the... 

Viscosity is often regulated by bubbling air through solutions of polysiloxanes or the liquid material itself. In this manner, alkyl side chains are oxidized and oxygen bridges set up between silicon atoms. Obviously, the greater the number of such cross links, other influences constant, the greater will be the viscosity... 

Stability constants for Cu11 complexation of Gly—X and X—Gly dipeptides show that even relatively small alkyl side chains can influence coordination. 3 At low pH, for example, the bidentate chelates N(amino),0(peptide) of L-Leu-Gly and L-Ile-Gly are the thermodynamically less stable, presumably due to steric hindrance from the branched side chains. Similar coordination by Gly—X is virtually independent of the nature of X. This latter result is not unexpected since only the Gly moiety is coordinating. However, on raising the solution pH (> 4) the peptide deprotonation that occurs to give tridentate N(amino),N(peptide),0(carboxyl) chelation is slightly inhibited by the Leu and lie residues (by 0.7-0.8 log units). 

The ratio of ferrocene-modified siloxane subunits to unsubstituted siloxane subunits rrv.n ratio) was varied as was the length (a ) of the alkyl side chain onto which the ferrocene moiety was attached as shown in Fig. 3.3. The electrode containing co-polymer with m n ratio of 1 1 or 1 2 was the more efficient electron relay systems. The ferrocene-modified homopolymer on the other hand loses flexibility due to steric hindrance caused by the side chain substitution by ferrocene, preventing efficient electron transfer from the enzyme to the electrode. The length of the alkyl side chain onto which the ferrocene moiety is attached was also found to influence the electron transfer efficiency of the electron relay system. Maximal current density was measured... 

Table 1. Influence of the substituents on the oxidation of alkyl side chains.

Three poly(n-alkyl acrylates) PA-H, PA-16, PA-18 and two poly-(vinyl alcohol aliphatic acid esters) PVA-1A and PVA-16 have been synthesized. They are white crystalline polymers at room temperature, characterized with IR, DSC, SALLS-photometer and polarizing microscope. Only PA-I4 and PVA-IZf are effective for 0/ diesel oil. The influences of molecular weight, molecular weight distribution and amount of addition of PA-1i+ and PVA-lif upon the pour-point depression of oil are very alike. These results reveal the length of n-alkyl side-chain of the polyesters plays the most important role in depressing the pour-point of petrolic oil and the order of linking in the ester group seems in no relation to this effect. 

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