Highly alkylated aromatic

Alkylated aromatics have excellent low temperature fluidity and low pour points. The viscosity indexes are lower than most mineral oils. These materials are less volatile than comparably viscous mineral oils, and more stable to high temperatures, hydrolysis, and nuclear radiation. Oxidation stabihty depends strongly on the stmcture of the alkyl groups (10). However it is difficult to incorporate inhibitors and the lubrication properties of specific stmctures maybe poor. The alkylated aromatics also are compatible with mineral oils and systems designed for mineral oils (see Benzene Toulene Xylenes and ethylbenzene). ... 

Alkylated aromatic lubricants, phosphate esters, polyglycols, chlorotrifluoroethylene, siUcones, and siUcates are among other synthetics that came into production during much that same period (28,29). Polyphenyl ethers and perfluoroalkyl polyethers have followed as fluids with distinctive high temperature stabiUty. Although a range of these synthetic fluids find appHcations which employ their unique individual characteristics, total production of synthetics represent only on the order of 2% of the lubricant market. Poly(a-olefin)s, esters, polyglycols, and polybutenes represent the types of primary commercial interest. 

A significant proportion of lube sulfonates are based on high molecular weight synthetic alkylated aromatic feedstocks. Sulfonation of these... 

An alternative copolymerization is illustrated by the method of Blasius. In this preparation, a phenol-formaldehyde (novolac) type system is formed. Monobenzo-18-crown-6, for example, is treated with a phenol (or alkylated aromatic like xylene) and formaldehyde in the presence of acid. As expected for this type of reaction, a highly crosslinked resin results. The method is illustrated in Eq. (6.23). It should also be noted that the additional aromatic can be left out and a crown-formaldehyde copolymer can be prepared in analogy to (6.22). ... 

Chlorine molecules are cleaved at high temperatures by photoinduced radical formation. By this means, a gas/liquid reaction can be performed in the side chain of alkyl aromatics quite selectively. The electrophilic ring substitution, instead, is favored using Lewis catalysts in polar solvents at low temperature. 

High molecular weight synthetic alkylated aromatic feedstocks, 23 533 High nuclearity carbonyl clusters, 16 64-66 High nuclearity metal carbonyl synthesis, 16 66-69 from salts, 16 68 from smaller carbonyls, 16 68-69 High ortho novolacs... 

As stated earlier, the benzene molecule is stabilized by strong resonance consequently, removal of a H from the ring by pyrolysis or 02 abstraction is difficult and hence slow. It is not surprising, then, that the induction period for benzene oxidation is longer than that for alkylated aromatics. The high-temperature initiation step is similar to that of all the cases described before, that is,... 

The first step of other high-order alkylated aromatics proceeds through pyrolytic cleavage of a CC bond. The radicals formed soon decay to give H atoms that initiate the H2—02 radical pool. The decay of the initial fuel is dominated by radical attack by OH and H, or possibly O and H02, which abstract an H from the side chain. The benzylic H atoms (those attached to the carbon next to the ring) are somewhat easier to remove because of their lower... 

The toxicities of nine alkyl aromatics (4) are appreciably less than those of the polycyclic aromatics. No signihcant retardation is observed in benzene-deuterium oxide exchange reactions at 30° even when the poisons are present in benzene in concentrations of 3.6 mole %. The high temperature exchange rate (Table II) of sterieally unhindered ring positions in the alkylbenzenes indicates that adsorption strength... 

Like aldehyde, the ketone function provides sufficient activation on an aromatic ring for the nucleophiUc substitution. Reduction of the carbonyl group after incorporation of the F-fluoride ion yields F-alkyl aromatics [177]. This methodology using F for trimethylammonium exchange, then reduction of the carbonyl compound, have proved to be useful for the synthesis of a [2- F]fluo-rophenol at high specific activity [141] (Scheme 39). 

The Heck reaction is well developed as a method for alkylating aromatics. Frank Glorius of the Max-Planck-lnstitute, Mulheim, reports (Tetrahedron Lett. 44 5751,2003) that chloroacetamides and bromoacelonitrile can also be activated by catalytic Pd to give the coupled products. This reaction works well with enol ethers, to give highly functionalized alkenes, but it also works well with a simple cyclic alkene. 

Chlorinated kerosene fractions, preferably those of highly paraffinic nature, have been widely used as intermediates in the manufacture of so-called keryl benzene detergents. The volume of chlorinated hydrocarbons so used represents an appreciable contribution to the important alkyl aromatic sulfonate detergent output. 

---