Resin acid
Resin acids or Resinosäuren, formerly Resinolsäuren, is the name for a highly diverse group of carboxylic acids that form the main components of natural resins. Its salts are called soaps resin or resinate. They are based, depending on the source of raw material frequently terpenes, but there are also aromatic carboxylic acids.
They are produced and stored in the plants in special structures and are among the secondary natural products. Resin acids have many functions in plants, including as protection against pests, mechanical damage and climatic fluctuations.
Occurrence and biosynthesis
In our part of the resin acids are mainly found in Coniferenharzen and belong to the group of diterpenes. Pines contain numerous vice bebene of parenchymal tissue radial and vertical channels that run through the wood, and in which collects the resin. In this case, the resin in the course of time, increasingly accumulated in heartwood and sapwood increased in the former at the lower part of the stem, while the amount of the resin increases in the sapwood to the height of the tree. Tritepernharzsäuren come, for example, elemi, dammar and mastic, aromatic acids in tolu balsam and incense before.
Resin acids are synthesized in different locations within the plant, as well as stored and transported to the outside, if necessary via channels. Their biosynthesis is part of the secondary metabolism of plants, and there are two synthetic routes. Terpenes via the mevalonate pathway in the endoplasmic reticulum and the MEP pathway synthesized in the plastids, aromatic resin acids on the Shikimisäureweg.
Properties
Resin acids have alicyclic structures and contribute next to the carboxyl group often have other functional groups such as hydroxy, keto, aldehyde or carboxylic acid ester. They are bad in water but well soluble in polar organic solvents such as chloroform or diethyl ether soluble. In the resin mixture, they are usually in acid form, but occasionally as an ester ago. They are very well crystallized and partially melt in the range 130-200 ° C. With bases ( sodium hydroxide, potassium hydroxide, calcium hydroxide) to form Resinate.
Classification
In addition to have significance for the industry resin acids of conifer, usually the molecular formula C20H30O2 ( diterpene ), also triterpene acids and benzoic and cinnamic acid derivatives occur. Together, they have their occurrence in natural resins and their origin from the secondary metabolism of plants. It is generally considered that resins acids of different botanical origin come from different chemical groups.
Diterpenes
- Abietane: abietic acid, neoabietic, levopimaric, palustric dehydroabietic
- Pimarane and Isopimarane: pimaric, sandaracopimaric, Podocarpinsäure
- Labdanes: Copalsäure, Eperuesäure, labdanolic, Polyalthinsäure, Pinifolsäure
Triterpenes
- Dammarane: Dammarolsäure
- Tirucallane: ( iso) Masticadienonsäure, Elemolsäure, Elemonsäure
- Oleananes: Oleanonsäure, oleanolic acid, Moron acid, α -boswellic acid
- Ursane: ursolic acid, Ursonsäure, β -boswellic acid
- Lupanes: Lupeolsäure
Other
Various resins, the aromatic acids cinnamic acid ( Akaroidharz ) and benzoic acid ( benzoic, incense, Tolu balsam, Peru balsam ), and benzyl and other esters of these acids.
Use
Sodium and potassium soaps of abietic acid formed as by- products of combustion process by the reaction of resin acid-containing wood with sodium hydroxide. It is a yellow gelatinous paste. After treating it with concentrated sulfuric acid is produced crude tall oil. This is further processed to recover the contained resin and fatty acids. From the contained resin acids, among other tall oil is produced, a rosin -like substance. It is used as an emulsifier in the production of synthetic rubber, as an additive to adhesives, printing inks, coatings and construction chemicals. Calcium and zinc resinates be used in paints, lead and Manganresinate as desiccants.