Isooctane 2,2,4-trimethylpentane

Internal rotation in isooctane (2,2,4-trimethylpentane) creates a large number of staggered conformations. However, only rotation about the C3-C4 bond produces conformations with different structures. Plot the energy of isooctane (vertical axis) vs. HCCCtBu torsion angle, i.e., about the C3-C4 bond (horizontal axis). How many minimum energy structures are there Are they all fully staggered Draw Newman projections that show the conformation of these structures. How does steric repulsion affect isooctane conformation ... 

Another interesting effect seen in alkanes is that increased branching lowers an alkane s boiling point. Thus, pentane has no branches and boils at 36.1 3C, isopentane (2-methylbutane) has one branch and boils at 27.85 °C, and neopentane (2,2-dimethylpropane) has two branches and boils at 9.5 °C. Similarly, octane boils at 125.7 °C, whereas isooctane (2,2,4-trimethylpentane) boils at 99.3 °C. Branched-chain alkanes are lower-boiling because they are more nearly spherical than straight-chain alkanes, have smaller surface areas, and consequently have smaller dispersion forces. 

Isooctane 2,2,4-trimethylpentane bums very smoothly in internal combustion engines and has an octane rating of 100. 

Toluene and isooctane (2,2,4-trimethylpentane) were obtained from the Fisher Scientific Company and used without further purification. 

Kretschmer, C.B., Nowakowska, J., Wiebe, R. (1948) Densities and liquid-vapor equilibria of the system ethanol-isooctane (2,2,4-trimethylpentane) between 0 and 50°. J. Am. Chem. Soc. 70, 1785-1790. 

The restriction for a nucleophile to penetrate and react with the confined cation-radical sometimes leads to unexpected results. Comparing the reactions of thianthrene cation-radicals, Ran-gappa and Shine (2006) refer to the zeolite situation. When thianthrene is absorbed by zeolites, either by thermal evaporation or from solution, thianthrene cation-radical is formed. The adsorbed cation-radical is stable in zeolite for a very long time. If isooctane (2,2,4-trimethylpentane) was used as a solvent, tert-butylthianthrene was formed in high yield. The authors noted it is apparent that the solvent underwent rupture, but the mechanism of the reaction remains unsolved. ... 

Asymmetric epoxidation of allylic alcohols is a very reliable chemical reaction. More than a decade of experience has confirmed that the Ti-tartrate catalyst is extremely tolerantof structural diversity in the allylic alcohol substrate for epoxidation yet is highly selective in its ability to discriminate between the enantiofaces of the prochiral olefin. Today the practitioner of organic chemistry need provide only the allylic alcohol to perform the reaction. All other reagents and materials required for the reaction are available from supply houses and usually are sufficiently pure as received to be used directly in the asymmetric epoxidation process. [When purchasing f-butyl hydroperoxide in prepared solutions, however, the more concentrated 5.5-M solution in isooctane (2,2,4-trimethylpentane) should always be chosen over the 3.0-M solution.] If the considerations presented in this chapter are observed, with attention to the moderately stringent technique outlined, no difficulty should be encountered in performing this reaction. 

A rating of the antiknock properties of a gasoline blend. Its octane number is the percentage of isooctane (2,2,4-trimethylpentane) in an isooctane/heptane blend that begins to knock at the same compression ratio as the gasoline being tested, (p. 97)... 

Polymerization was effected batch-wise in 600 ml. solvent at atmospheric pressure in a 1000-ml. three-necked flask provided with a stirrer and connected to a buret for catalyst and solvent supply. Isooctane (2,2,4-trimethylpentane) was used as the main polymerization solvent. About 7% of rc-decane was present in this solvent if the catalyst had been reduced at 170° C. 

Use SpartanBuild to construct a model of isooctane (2,2,4-trimethylpentane). How many different staggered conformations can you generate by bond rotation about the C-C bonds in this molecule Build each of the staggered conformers and minimize their energies. What are their relative strain energies Explain. 

It is used as a solvent and raw material for organic synthesis reactions and is a very important chemical in the petroleum industry. It is also widely used in the rubber and paper processing industries. Isooctane, along with other n- and isoparaffins, are used in the blending of fuels to achieve desired antiknock properties. A total of 17 isomers of octane are known to exist isooctane (2,2,4-trimethylpentane) is a principal ingredient of gasoline. 

The following is an example of an alkylation reaction that is important in the production of isooctane (2,2,4-trimethylpentane) from two components of crude oil isobutane and isobutene. Isooctane is an antiknock additive for gasoline. 

The burning properties of hydrocarbons depend on their structure. Isooctane (2,2,4-trimethylpentane) is the standard used to assign octane ratings. The octane rating is an arbitrary scale for rating the relative knocking prop-... 

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