Resin acid refers to mixtures of several related carboxylic acids, primarily abietic acid, found in tree resins. Nearly all resin acids have the same basic skeleton: three fused rings having the empirical formula C19H29COOH. Resin acids are tacky, yellowish gums that are water-insoluble. They are used to produce soaps for diverse applications, but their use is being displaced increasingly by synthetic acids such as 2-ethylhexanoic acid or petroleum-derived naphthenic acids.
Resin acids are protectants and wood preservatives that are produced by parenchymatous epithelial cells that surround the resin ducts in trees from temperate coniferous forests. The resin acids are formed when two-carbon and three-carbon molecules couple with isoprene building units to form monoterpenes (volatile), sesquiterpenes (volatile), and diterpenes (nonvolatile) structures.
Pines contain numerous vertical and radial resin ducts scattered throughout the entire wood. The accumulation of resin in the heartwood and resin ducts causes a maximum concentration in the base of the older trees. Resin in the sapwood, however, is less at the base of the tree and increases with height.
In 2005, as an infestation of the Mountain pine beetle (Dendroctonus ponderosae) and blue stain fungus devastated the Lodgepole Pine forests of northern interior British Columbia, Canada, resin acid levels three to four times greater than normal were detected in infected trees, prior to death. These increased levels show that a tree uses the resins as a defense. Resins are both toxic to the beetle and the fungus and also can entomb the beetle in diterpene remains from secretions. Increasing resin production has been proposed as a way to slow the spread of the beetle in the "Red Zone" or the wildlife urban interface.
Several important resin acids are obtained from rosin, as listed below. [1] The two classes, abietic acids and pimaric acids, are isomers with the formula C19H29CO2H.
The commercial manufacture of wood pulp grade chemical cellulose using the kraft chemical pulping processes releases resin acids. The Kraft process is conducted under strongly alkaline conditions of sodium hydroxide, sodium sulfide, and sodium hydrosulfide. These bases neutralize resin acids, converting them to their respective sodium salts, sodium abietate, ((CH3)4C15H17COONa), sodium pimarate ((CH3)3(CH2)C15H23COONa) and so on. In this form, the sodium salts are poorly insoluble and, being of lower density than the spent pulping process liquor, float to the surface of storage vessels during the process of concentration, as a somewhat gelatinous pasty fluid called kraft soap (also called resin soap). [2]
Kraft soap can be reneutralized with sulfuric acid to restore the acidic forms abietic acid, palmitic acid, and related resin acid components. This refined mixture is called tall oil. Other major components include fatty acids and unsaponifiable sterols.
Resin acids, because of the same protectant nature they provide in the trees where they originate, also impose toxic implications on the effluent treatment facilities in pulp manufacturing plants. Furthermore, any residual resin acids that pass the treatment facilities add toxicity to the stream discharged to the receiving waters.
The chemical composition of tall oil varies with the species of trees used in pulping, and in turn with geographical location. For example, the coastal areas of the southeastern United States have a high proportion of Slash Pine (Pinus elliottii); inland areas of the same region have a preponderance of Loblolly Pine (Pinus taeda). Slash Pine generally contains a higher concentration of resin acids than Loblolly Pine.
In general, the tall oil produced in coastal areas of the southeastern United States contains over 40% resin acids and sometimes as much as 50% or more. The fatty acids fraction is usually lower than the resin acids, and unsaponifiables amount to 6-8%. Farther north in Virginia, where Pitch Pine (Pinus rigida)and Shortleaf Pine (Pinus echinata) are more dominant, the resin acid content decreases to as low as 30-35% with a corresponding increase in the fatty acids present.
In Canada, where mills process Lodgepole Pine (Pinus contorta) in interior British Columbia and Alberta, Jack Pine (Pinus banksiana), Alberta to Quebec and Eastern White Pine (Pinus strobus) and Red Pine (Pinus resinosa), Ontario to New Brunswick, resin acid levels of 25% are common with unsaponifiable contents of 12-25%. Similar variations may be found in other parts of the United States and in other countries. For example, in Finland, Sweden and Russia, resin acid values from Scots Pine (Pinus sylvestris) may vary from 20 to 50%, fatty acids from 35 to 70%, and unsaponifiables from 6 to 30%.
Resin acids are very poorly soluble in water (milligrams per liter) and have low acute toxicity. [3]
In polymer chemistry and materials science, a resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses mainly on naturally occurring resins.
Turpentine is a fluid obtained by the distillation of resin harvested from living trees, mainly pines. Principally used as a specialized solvent, it is also a source of material for organic syntheses.
The Pinaceae, or pine family, are conifer trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, piñons, larches, pines and spruces. The family is included in the order Pinales, formerly known as Coniferales. Pinaceae have distinctive cones with woody scales bearing typically two ovules, and are supported as monophyletic by both morphological trait and genetic analysis. They are the largest extant conifer family in species diversity, with between 220 and 250 species in 11 genera, and the second-largest in geographical range, found in most of the Northern Hemisphere, with the majority of the species in temperate climates, but ranging from subarctic to tropical. The family often forms the dominant component of boreal, coastal, and montane forests. One species, Pinus merkusii, grows just south of the equator in Southeast Asia. Major centres of diversity are found in the mountains of southwest China, Mexico, central Japan, and California.
Rosin, also called colophony or Greek pitch, is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black. At room temperature rosin is brittle, but it melts at stove-top temperature. It chiefly consists of various resin acids, especially abietic acid. The term colophony comes from colophonia resina, Latin for "resin from Colophon", an ancient Ionic city. It is an FDA approved food additive.
Abietic acid is a mild organic acid found in coniferous trees.
Pinus rigida, the pitch pine, is a small-to-medium-sized pine. It is native to eastern North America, primarily from central Maine south to Georgia and as far west as Kentucky. It is found in environments which other species would find unsuitable for growth, such as acidic, sandy, and low-nutrient soils.
Pinus koraiensis is a species of pine known commonly as the Korean pine. It is a relic species of the Tertiary, identified as a rare tree species by United Nations. It is native to eastern Asia: Korea, northeastern China, Mongolia, the temperate rainforests of the Russian Far East, and central Japan. In the north of its range, it grows at moderate elevations, typically 600 to 900 metres, whereas further south, it is a mountain tree, growing at 2,000 to 2,600 m elevation in Japan. Other common names include Chinese pinenut. The ancient woodland of P. koraiensis on the earth is about 50 million hectares, and China has about 30 million hectares, accounting for 60%. It is a second-class national key protected plant in China. P. koraiensis is a tree species with high economic and ecological value. The official name in Chinese is "红松 hóng sōng/red pine", because almost every part of it is related to red.
The kraft process (also known as kraft pulping or sulfate process) is a process for conversion of wood into wood pulp, which consists of almost pure cellulose fibres, the main component of paper. The kraft process involves treatment of wood chips with a hot mixture of water, sodium hydroxide (NaOH), and sodium sulfide (Na2S), known as white liquor, that breaks the bonds that link lignin, hemicellulose, and cellulose. The technology entails several steps, both mechanical and chemical. It is the dominant method for producing paper. In some situations, the process has been controversial because kraft plants can release odorous products and in some situations produce substantial liquid wastes.
The mountain pine beetle is a species of bark beetle native to the forests of western North America from Mexico to central British Columbia. It has a hard black exoskeleton, and measures approximately 5 millimetres, about the size of a grain of rice.
In industrial chemistry, black liquor is the by-product from the kraft process when digesting pulpwood into paper pulp removing lignin, hemicelluloses and other extractives from the wood to free the cellulose fibers.
Resin soap is a mix of salts of resin acids. It is a yellow gelatinous pasty soap with use in bleaching and cleaning and as a compound of some varnishes. It also finds use in rubber industry as an emulsifier. Often the soap is pretreated with formaldehyde and maleic anhydride.
Tall oil, also called liquid rosin or tallol, is a viscous yellow-black odorous liquid obtained as a by-product of the kraft process of wood pulp manufacture when pulping mainly coniferous trees. The name originated as an anglicization of the Swedish tallolja. Tall oil is the third largest chemical by-product in a kraft mill after lignin and hemicellulose; the yield of crude tall oil from the process is in the range of 30–50 kg / ton pulp. It may contribute to 1.0–1.5% of the mill's revenue if not used internally.
Gordonia lasianthus is a small to medium-sized evergreen tree or shrub found in acidic, swampy soils of pinelands and bays on the Atlantic and Gulf Coastal Plains of the southeastern United States. It is a member of the tea or family Theaceae. It is slow growing with soft, light-colored, fine-grained wood of little commercial value, although loblolly-bay could be managed as a source of pulpwood. When older specimens are cut, the wood exudes a strong scent. It is similar to a mixture of fresh oranges and pine sap. The bark of the adult tree varies from medium grey to a red brown coloration. Dead adult specimens of loblolly bay exhibit a lustrous shine when exposed to sunlight for several years. The white showy flowers and shiny foliage make it a desirable ornamental, but it is not easy to cultivate. Deer browse stump sprouts heavily.
The enzyme abieta-7,13-diene synthase catalyzes the chemical reaction
In industrial paper-making processes, organosolv is a pulping technique that uses an organic solvent to solubilise lignin and hemicellulose. It has been considered in the context of both pulp and paper manufacture and biorefining for subsequent conversion of cellulose to fuel ethanol. The process was invented by Theodor Kleinert in 1968 as an environmentally benign alternative to kraft pulping.
Levopimaric acid is an abietane-type of diterpene resin acid. It is a major constituent of pine oleoresin with the chemical formula of C20H30O2. In general, the abietene types of diterpene resin acid have various biological activities, such as antibacterial, cardiovascular and antioxidant. Levopimaric acid accounts for about 18 to 25% of pine oleoresin. The production of oleoresin by conifer species is an important component of the defense response against insect attack and fungal pathogen infection.
Resin canals or resin ducts are elongated, tube-shaped intercellular spaces surrounded by epithelial cells which secrete resin into the canal. These canals are orientated longitudinally and radially in between fusiform rays. They are usually found in late wood: denser wood grown later in the season. Resin is antiseptic and aromatic and prevents the development of fungi and deters insects.
Abieta-7,13-diene hydroxylase (EC 1.14.13.108) is an enzyme with systematic name abieta-7,13-diene,NADPH:oxygen oxidoreductase (18-hydroxylating). This enzyme catalyses the following chemical reaction
Abieta-7,13-dien-18-ol hydroxylase (EC 1.14.13.109, CYP720B1, PTAO) is an enzyme with systematic name abieta-7,13-dien-18-ol,NADPH:oxygen oxidoreductase (18-hydroxylating). This enzyme catalyses the following chemical reaction