2.4- Dimethylpentane, investigations

At 180° and 40 atmospheres pressure, other investigators obtained a 65% yield of polymer hydrogenation of whieh yielded a liquid containing 54% of heptane fraction consisting of approximately 20% of 2,2-dimethylpentane and 80% of 2,3-dimethylpentane (Hoog et al., 34). 

The synergistic effect often observed in bimetallic systems was further explored by Garland and coworkers. The hydroformylation of 3,3-dimethylbut-l-ene to form 4,4-dimethylpentanal in >95% selectivity at room temperature with [Rli4(CO)i2]-[Mn2(CO)io/HMn(CO)5] as catalyst coprecursors was investigated using in situ PT-IR spectroscopic techniques and kinetic studies revealing evidence of a bimetallic catalytic binuclear elimination reaction (CBER). 

Recently, however, two pieces of direct experimental evidence have become available. First, in a low temperature (100 °C) liquid-phase investigation of the oxidation of 2,4-dimethylpentane Mill [105] found Ai4/5 = 10 ° sec" and ,4 = 15 kcal. mole" for... 

The composition of a large number of alkylates, both those prepared in the laboratory using pure hydrocarbons and those obtained on a commercial scale using olefin mixtures, has been investigated. The principal products are for the most part similar to those obtained in the presence of the metal halide catalyst, the chief difference being in the relative amounts of the various isomers. Alkylation of isobutane ivith propene at 30° in the presence of 98% sulfuric acid yielded an alkylate that was 62-66% by weight 2,3-dimethylpentane and 8-12%, 2,4-dimethylpentane propane and trimethylpentanes (11-19%) were also obtained (McAllister et al., 12). A commercial isobutane-propene alkylate obtained at 21° was shown to contain about 36% by volume of 2,3- and 26% of 2,4-dimethylpentane as well as 15% of trimethylpentanes (Glasgow et al., 40). 

Badina, N. S. Sabylin, I. L Kharisov, M. A. Yablochkina, M. N. Investigation and calculation of the liquid-vapor phase equilibrium in the three-component system toluene-2,2-dimethylpentane-ethylben-zene [Russ.]. Zh. Prikl. Khim. (Leningrad) 1977, 50, 2478-2480. 

As in the case of sec-alcohols, ruthenium complex has also been investigated as a catalyst in the racemization of primary amines. In fact, Shvo s complex 2 (Figure 14.3) was employed by the Backvall s group as the catalyst of the racemization of amines under transfer hydrogenation conditions [105]. However, temperatures up to 110 °C were required for amine racemization, incompatible with the lipase resolution, and furthermore, side products were formed in the medimn and a hydrogen source was needed. To avoid these drawbacks, the racemization at high temperature was carried out after a first lipase-catalyzed KR, followed by a second KR process, and a hydrogen source such as 2,4-dimethylpentan-3-ol was employed. 

Oxidation mechanisms have been investigated for a number of larger aldehydes, using chamber methods with end product analysis. Tuazon et al. (2003) studied the mechanism of the reaction of OH radicals with 2,3-dimethylpentanal. They found that acetaldehyde and 2-butanone were the main products with a small yield (5.4%) of 3-methyl-2-pentanone. The latter product arises exclusively from abstraction at the 2-position, adjacent to the carbonyl group the equivalent abstraction is excluded from the butanal mechanism for the sake of clarity. 

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