What is nc4 hydrocarbon

Hydrocarbons

The Hydrocarbons are a group of chemical compounds that only consist of carbon and hydrogen[1] and form carbon chains, rings, or combinations thereof. The group of substances is diverse. There are several subgroups such as alkanes, cycloalkanes, alkenes, alkynes and aromatics (arenes) as well as many compounds in this class. The hydrocarbons have achieved great technical importance primarily due to their huge deposits as fossil fuels and in organic synthesis.

Occurrence

The hydrocarbons are naturally contained in oil, natural gas, coal and other fossil substances in large quantities. They are common in many plants e.g. B. as terpenes, carotenoids and rubber. Simple hydrocarbons are metabolic products of some microorganisms. In space, the hydrocarbons, mostly in the form of methane and ethane, can be found on comets, planetary atmospheres and in interstellar matter.

Systematics

Hydrocarbons can be divided into saturated, unsaturated and aromatic hydrocarbons.

At saturated Hydrocarbons are chemical compounds that only contain C-C single bonds. They are divided into chain-shaped and ring-shaped connections. Chain forms are systematically referred to as alkanes. The simplest and best-known alkanes are methane (CH4), Ethane (C.2H6), and propane (C.3H8). In general, the empirical formula for the homologous series of chain-like alkanes is C.nH2n + 2. Ring-shaped alkanes are known as cycloalkanes. Your general empirical formula for the homologous series is C.nH2n.

Unsaturated Hydrocarbons can be divided into alkenes and alkynes. The alkenes are compounds that contain C-C double bonds. The simplest representative of this group of substances is ethene, also called ethylene (C.2H4). The simplest n-Alkenes with only one double bond generally have the empirical formula C.nH2n. Compounds with at least two C-C double bonds, such as, for example, 1,3-butadiene, are referred to as polyenes. Cycloalkenes are cyclic hydrocarbons such as cyclopentadiene. Here there are C-C double bonds within a carbon ring. Alkynes are hydrocarbons that contain one or more C-C triple bonds. The best-known representative is ethyne (acetylene) with the empirical formula C.2H2. Accordingly, alkynes with a triple bond generally have the empirical formula for the homologous series C.nH2n-2. Saturated and unsaturated hydrocarbons are collected under the name of aliphatic hydrocarbons, especially in the petrochemical industry.

The last important group of hydrocarbons are the aromatic Hydrocarbons. These are hydrocarbons that have aromaticity and mostly C.6- Own rings (Arene). The best-known representative is benzene (C.6H6). The polycyclic aromatic hydrocarbons are a subgroup of aromatics. They are compounds that consist of several benzene rings attached to one another. A well-known representative is naphthalene (C.10H8).

Hydrocarbons, which correspond in structure to Platonic solids, are called Platonic hydrocarbons. These include tetrahedrane, cubane and dodecahedrane.

Hydrocarbons with the same empirical formula can have different structural formulas (links between the carbon atoms). They are then constitutional isomers. They are found in alkanes from butanes and in most other hydrocarbons. The classic cis-trans isomerism sometimes occurs on C-C double bonds. As the example 3-methylhexane shows, simple branched hydrocarbons can be chiral. The carbon atom in position number 3 becomes the stereocenter, the connection is asymmetric and a distinction is made between the R and S enantiomers.

properties

Hydrocarbons are insoluble in water, but readily soluble in most organic solvents. This means that hydrocarbons are hydrophobic, i.e. also lipophilic.

Gaseous hydrocarbons burn very quickly and with a hot flame; the energy released is great. Liquid hydrocarbons with a low boiling point evaporate easily; Due to their low flash point, fires are easy to start. The optimal (complete) combustion of hydrocarbons produces water and carbon dioxide, and insufficient (incomplete) combustion can also produce carbon monoxide or carbon (soot). The reactivity of the alkanes depends on their chain length. Long-chain alkanes are relatively inert (not very reactive). If hydrocarbons burn with a sooty flame, this can also be an indication of a higher carbon content in the compound (longer chain length).

In addition to redox reactions when they are burned, alkanes enter into substitution reactions, whereby hydrogen atoms can be exchanged for other atoms and groups of atoms, but mainly halogens. Alkenes and alkynes, on the other hand, are very reactive and react with many substances by adding to the C-C multiple bond (addition reaction).

use

Alkanes are often used as fossil fuels in mixtures such as biogas, liquid gas, gasoline, diesel fuel, heating oil, kerosene and petroleum. The most important alkanes are the low molecular weight alkanes methane, ethane and propane. Alkanes like n-Butane, isopentane, various hexanes and the cycloalkane-cyclohexane are components in motor gasoline.

The hydrocarbons serve as the starting material for a large number of industrially important chemical synthesis processes. Alkenes such as ethene and cyclohexene, alkynes such as ethyne and polyenes such as 1,3-butadiene, isoprene and cyclopentadiene are of industrial importance. Many arenes are of industrial importance, including benzene, toluene, xylene and styrene.

The polymerization products of hydrocarbons, such as polystyrene, polyethylene, polypropylene, polyethine, many copolymers and halogenated hydrocarbon polymers such as polyvinyl chloride and polytetrafluoroethylene are important. In addition, hydrocarbons serve as lipophilic solvents.

Ecological damage

Making hydrocarbons - as defined by the World Health Organization WHO - the main part of the volatile organic compounds (abbreviated also VOC) from; if they are emitted, these are considered to be environmentally damaging. In order to reduce emissions, z. B. in Switzerland levied an incentive tax on these emissions. Methane gas also has a significant greenhouse effect.[2]

See also

  • Bridged hydrocarbons

literature

  • Handbook of Experimental Chemistry Upper Secondary Area, Volume 9, Hydrocarbon, Aulis Verlag Deubner & Co. KG
  • Karl-Heinz Lautenschläger, Werner Schröter, Joachim Teschner, Hildegard Bibrack, Paperback of Chemistry, 18th edition, Harri Deutsch, Frankfurt (Main), 2001.
  • J. C. Jones: Hydrocarbons. Physical Properties and their Relevance to Utilization. J. C. Jones & Ventus Publishing ApS, 2010. ISBN 978-87-7681-513-4 (PDF at bookboon.com).

Web links

Individual evidence

  1. ↑ Entry: hydrocarbons. In: IUPAC Compendium of Chemical Terminology (the “Gold Book”). doi: 10.1351 / goldbook.H02889 (Version: 2.3.2).
  2. ↑ BUWAL: Air pollution control in the cantons, 1997.