Reminders of the concepts of organic chemistry

Overview

Organic chemistry is the branch of chemistry that studies carbon compounds and their combinations. Many varieties of substances consisting of organic molecules, such as food, medicines, plastics, etc..

In this paper, we recall some concepts of organic chemistry to understand the terms being discussed in the sections on food chemistry.

Hydrocarbons

Hydrocarbons are organic compounds made of carbon and hydrogen. The organic compounds are the simplest, and can be considered as other organic compounds are derived. The hydrocarbons are of great commercial importance: they are used as fuels, as fuels, such as lubricating oils and products of basic petrochemical synthesis.

It distinguishes aliphatic (open chain) and cyclic compounds. In the open-chain compounds containing more carbon atoms, they are connected to each other to form an open channel may be one or more branches. In cyclic compounds, carbon atoms form one or more closed rings. Both groups are subdivided into saturated compounds (containing only single bonds) and unsaturated (containing at least one double bond).

Aliphatic hydrocarbons

Aliphatic hydrocarbons are compounds containing more carbon atoms connected to each other to form an open channel may be one or more branches. Depending on the nature of carbon-carbon (saturated or unsaturated), on the class into alkanes, alkenes and alkynes.

Aliphatic hydrocarbons

Alkanes

The alkanes are saturated open chain of general formula C_nH_{2n +2}(n is the number of carbon atoms in the molecule).

To designate alkanes, using Greek prefixes indicating the number of carbon atoms, followed by-ane: methane (CH₄), ethane (C₂H₆), propane (C₃H₈), butane (C₄H₁₀), etc..

A molecule is called linear when the channel is straight, is it contains branched side chains, or branches.

Alkenes

Alkenes or olefins are unsaturated acyclic hydrocarbons (aliphatic) having a double carbon-carbon (C = C), general formula C_nH_2n, where n is the number of carbon atoms in the molecule. The first term of the series and the oldest known ethylene (or ethene, according to the rules of the IUPAC nomenclature), of formula C₂H₄, so that the alkenes are often called ethylenic hydrocarbons.

The nomenclature used is the same as that on alkanes; replace the suffix "ane" to "ene", and indicates the position of the double bonds before the name of the main chain:

A compound containing two double bonds C = C is a diene (general formula C_nH_2n-2),such as 3-methyl-2 ,4-hexadiène:

Alkynes

The alkynes are unsaturated acyclic hydrocarbons containing a triple bond C ≡ C. Their general formula C_nH_2n-2(where n is the number of carbon atoms in the molecule).

The nomenclature used is the same as that on alkanes; replace the suffix "ane" to "yne", and indicates the position of the triple bond before the name of the main chain.

It distinguishes true alkynes (MONOSUBSTITUTED) of general formula R-C ≡ C-H, which disubstitution of alkynes derived formula R-C ≡ C-R' (R and R' are alkyl groups identical or different) , due to the chemical properties of hydrogen terminal alkynes true. The alkynes are also called "acetylenic hydrocarbons", named after first use of the term of the series, acetylene (or éthyne, according to the IUPAC nomenclature rules) of formula C₂H₂.

Cyclic hydrocarbons

The homocycles have a cycle consisting solely of carbon atoms, heterocycles have one or more rings contain one or more heteroatoms, different elements carbon and hydrogen (O, N, S, etc.).. Among the carbon cycle , there are Cyclanes the cyclenes and cyclynes.

Saturated rings

Of molecular formula C_nH_2n, Cyclanes the rings are saturated isomers of alkanes. The names given them by IUPAC are counterparts to the nomenclature used for alkanes. Here are two examples of Cyclanes:

Apart from cyclopropane, the Cyclanes are a part of regular gasoline. Several unsaturated cyclic hydrocarbons, general formula C₁₀H₁₆, are in the perfumed natural essences that are distilled from plants. These hydrocarbons are called terpenes pinene and include (in turpentine) and limonene (in the essences of lemon and orange).

Cycles unsaturated

The cycle of cyclenes have one double bond C = C and that of cyclynes, volatile compounds, contains a triple bond C ≡ C. Alpha-pinene and vitamin A are two cyclenes:

Heterocycles

The cycle of a molecule may contain different carbon atoms, then called heteroatoms. The most common heteroatoms are sulfur, nitrogen and oxygen. You can also meet with the boron, phosphorus and selenium:

Aromatic hydrocarbons

An aromatic hydrocarbon is a substance whose molecules have a ring of six unsaturated carbon atoms. The electrons involved in the ring are delocalized over the cycle. Thus, it is often the benzene molecule as follows:

Other examples:

Alcohols

Alcohols are organic compounds containing the hydroxyl group-OH bound to a saturated carbon atom. The general formula of alcohols is R-OH, where R is an alkyl group (C_nH_{2n +1,}where n is the number of carbon atoms in the molecule).

In common parlance, the term alcohol refers to ethyl alcohol, or ethanol. The name is derived from Arabic al-kuhl, or al koh'l, which denotes a fine powder made of antimony sulphide. Then, the name meaning of alcohol has widened to refer to any fine powder.

The name of the alcohol is formed by adding the suffix ol on behalf of the hydrocarbon with the same number of carbon atoms as the main chain.

Alcohols that have one, two or three-OH hydroxyl groups are called monohydric, diols and triol; they have more than three hydroxyl groups-OH, are polyols. There are three classes of alcohols based on the number of hydrogen atoms attached to the carbon atom bearing the OH group (carbon functional) primary alcohols of formula RCH₂OH, the secondary alcohols R₂CHOH and tertiary alcohols R₃COH, R groups are alkyl groups.

Enols and phenols

The Enola, compounds in which the group-OH is bound to an unsaturated carbon atom or phenols in which the group is linked to an aromatic ring.

The enols and phenols are not spirits.

Aldehydes

Aldehydes are organic compounds of general formula R-CHO where R represents either a hydrogen atom or a hydrocarbon group or aliphatic cyclic (respectively alkyl or aryl group).

Examples:

Ketones

Ketones are organic compounds of general formula R-CO-R ', where R and R' are organic radicals. The simplest ketone is acetone or propanone, formula CH₃-CO-CH₃.

Aldehydes, such as ketones, include functional group C = O, called carbonyl group. These carbonyl compounds are distinguished solely by the number of alkyl or aryl groups linked to carbon functional (one for two for aldehydes and ketones). Therefore, aldehydes and ketones have many similarities.
Examples:

Esters

Esters are organic compounds of general formula:

R1 and R2 are alkyl groups or phenyl.

Examples:

Cyclic esters are called lactones.

Ethers

Ethers are organic compounds of general formula R1-O-R2, where O is an oxygen atom, R1 and R2 are organic radicals identical or different.

Example:

Amides

Amides are organic compounds containing the CONH₂radical. The amides are a large family of chemical compounds. They are widespread in nature, the most common being urea, diamide containing no hydrocarbon. Proteins and peptides are composed of amides. Nylon is a long chain polyamide.

Example:

Imides

The functional group of an imide has two acyl groups bound to the same nitrogen atom. So these are secondary amides. Can be seen as analogues of anhydrides nitrogen. The terms are the most important cyclic imides such as succinimide or phthalimide.

Amines

Amines are organic nitrogen compounds obtained by substitution of one or more hydrogen atoms on the molecule of ammonia (NH₃) by hydrocarbon groups (or alkyl).

There are three classes of amines according to the number of hydrogen atoms substituted:

A primary amine has the general formula R-NH₂, a secondary amine has the formula (R, R)-NH and a tertiary amine groups alkyl (or aryl) associated with the nitrogen atom. Amino acids, biologically important functions include amines.

Examples:

Caffeine (C) may be extracted from coffee and tea. Theobromine (T) is contained in cocoa.

Nitriles

Nitriles known organic compounds containing the cyano group bound to an alkyl chain or phenyl. They have the following general formula: RC ≡ N

Examples:

The acetonitrile éthanenitrile is known in the industry. It is used as an industrial solvent in the selective extraction of waxes and fats.

The benzonitrile or phenyl cyanide is used as a solvent and as feedstock in pharmaceutical chemistry.

Carboxylic acids

Carboxylic acids are organic acids having one or more carboxylic groups (-COOH). Carboxylic acid is the simplest acid formic acid (methano). Acetic acid (ethanoic acid) is diluted familiar form: it is the vinegar.

Examples:

The names of the carboxylate ions are formed from those of parent acids by replacing the suffix oic oate by or by the suffix ic ate.

Amino acids

Amino acids (or amino acids) are organic compounds containing the amino group (-NH₂) and carboxyl group (-COOH).

Alpha-amino acids are the basic constituents of proteins and are semi-developed formula generally follows:

As shown in the formula, the amino and carboxyl groups are bound to the same atom, the carbon atom alpha. It is through the R group that molecules of amino acids differ from each other.