Organic Chemistry: Alkanes and Heterocycles

Alkenes and cycloalkanes have the same molecular formula (C_nH_2n). Since cycloalkanes do not behave as unsaturated hydrocarbons, alkenes and cycloalkanes are termed functional isomers. For instance, propene is isomeric with cyclopropane (or trimethylene).

Diazirines are a class of organic molecules consisting of a carbon bound to two nitrogen atoms, which are double-bonded to each other, forming a cyclopropene-like ring. They are mainly used as carbene precursor and also in photoaffinity labelling studies of nucleic acids and proteins.

Nonacosane is a straight-chain hydrocarbon. It has 1,590,507,121 constitutional isomers. Nonacosane has been reported to be a component of a pheromone of Orgyia leucostigma, and evidence suggest it plays a role in the chemical communication of several insects, including the female Anopheles stephensi mosquito.

Piperazine is an organic compound that consists of a six-membered ring containing two opposing nitrogen atoms. Piperazine exists as small alkaline deliquescent crystals with a saline taste.

2,2-Dimethylbutane, trivially known as neohexane, is an organic compound with formula C₆H₁₄ or (H₃C-)₃-C-CH₂-CH₃. It is therefore an alkane, indeed the most compact and branched of the hexane isomers — the only one with a quaternary carbon and a butane (C₄) backbone.

Octane rating or octane number is a standard measure of the anti-knock properties (i.e. the performance) of a motor or aviation fuel. The higher the octane number, the lesser likely is the fuel to ignite prematurely in the engine's cycle and cause the engine damage. In broad terms, fuels with a higher octane rating are more suitable for high-performance engines.

Thiirane, more commonly known as ethylene sulphide, is the cyclic chemical compound with the formula C₂H₄S. It is the smallest suphur-containing heterocycle. Like many organosulphur compounds, this species has a stench. Thiirane is also used to describe any derivative of the parent ethylene sulphide.

Thietane is a heterocyclic compound containing a saturated four-membered ring with three carbon atoms and one sulphur atom.

Thiete is a heterocycle. It is more commonly encountered not on its own, but in anellated derivatives, several of which have been synthesized. Thietes are generally not very stable.

It has five rings. It also has the faint aromatic odour. Pure benzo[a]pyrene is pale yellow, and is found as monoclinic or orthorhombic crystals. These can be separated from a mixture of polynuclear aromatic hydrocarbons using various standard separation techniques and recrystallized from benzene and methanol. It is known as human carcinogen.

Pentane is an organic compound, with five carbon atoms. Pentane is one of the primary blowing agents used in the production of polystyrene foam. Because of its low boiling point, low cost and relative safety, pentane is used as a working medium in geothermal power stations. It is added into some refrigerant blends as well.

Triptane, or 2,2,3-trimethylbutane, is an organic chemical compound with the molecular formula C₇H_16. It is therefore an alkane, specifically the most compact and heavily branched of the heptane isomers, the only one with a butane (C4) backbone. Triptane is commonly used as an anti-knock additive in aviation fuels.

It is a light oily hydrocarbon, of the marsh-gas series. It contains fourteen carbon atoms in the molecule.

Undecane (also known as hendecane) is a liquid alkane hydrocarbon. It is used as a mild sex attractant for various types of moths and cockroaches, and an alert signal for a variety of ants. It has 159 isomers. Undecane may also be used as an internal standard in gas chromatography when working with other hydrocarbons.

The final type of octane rating, called Observed Road Octane Number (RdON), is derived from testing gasolines in real world multi-cylinder engines, normally at wide open throttle. It was developed in the 1920's and is still reliable today. The original testing was done in cars on the road but as technology developed, the testing was moved to chassis dynamometers with environmental controls to improve consistency.

The Nysted reagent is used for the olefination of ketones and aldehydes.

The Cornforth salt or pyridinium dichromate (PDC) is a pyridinium salt of dichromate. It is a strong oxidizing agent which can convert primary and secondary alcohols to ketones. In its chemical structure and functions, it is closely related to other compounds made from hexavalent chromium oxide, such as pyridinium chlorochromate and Collins reagent.

Diethylzinc is an organozinc compound composed of zinc bonded to two ethyl groups. This colourless liquid is an important reagent in organic chemistry and available commercially as solutions of hexanes, heptane or toluene.