Editing Resin (section)

=== Rosin ===
{{see also|Rosin}}
[[File:Araucaria Resin.JPG|thumb|right|Extremely [[Viscosity|viscous]] resin extruding from the trunk of a mature ''[[Araucaria columnaris]]''.]]

[[Rosin]] is a solidified resin from which the [[Volatility (chemistry)|volatile]] [[terpene]]s have been removed by distillation. Typical rosin is a transparent or translucent mass, with a vitreous fracture and a faintly yellow or brown colour, non-odorous or having only a slight turpentine odour and taste. Rosin is insoluble in water, mostly soluble in alcohol, [[essential oil]]s, [[diethyl ether|ether]], and hot fatty oils.  Rosin softens and melts when heated and burns with a bright but smoky flame.

Rosin consists of a complex mixture of different substances including organic acids named the [[resin acid]]s. Related to the terpenes, resin acid is [[oxidation|oxidized]] terpenes. Resin acids dissolve in [[alkali]]s to form [[resin soap]]s, from which the resin acids are regenerated upon treatment with acids. Examples of resin acids are [[abietic acid]] (sylvic acid), C<sub>20</sub>H<sub>30</sub>O<sub>2</sub>, [[plicatic acid]] contained in cedar, and [[pimaric acid]], C<sub>20</sub>H<sub>30</sub>O<sub>2</sub>, a constituent of [[galipot]] resin. Abietic acid can also be extracted from rosin by means of hot alcohol. 

Rosin is obtained from [[pine]]s and some other [[plant]]s, mostly [[Pinophyta|conifers]].<ref name=Ullmann>{{cite encyclopedia|doi=10.1002/14356007.a23_073 |chapter=Resins, Natural |encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry |year=2000 |last1=Fiebach |first1=Klemens |last2=Grimm |first2=Dieter |isbn=978-3-527-30673-2|publisher=Wiley-VCH|location=Weinheim}}</ref> Plant resins are generally produced as stem secretions, but in some Central and South American species of ''[[Dalechampia]]'' and ''[[Clusia]]'' they are produced as pollination rewards, and used by some [[stingless bee]] species in nest construction.<ref>{{cite journal | first1=V. | last1=Bittrich | first2= Maria C. E. | last2= Amaral | year=1996 | title=Flower morphology and pollination biology of some Clusia species from the Gran Sabana (Venezuela) | journal=Kew Bulletin | volume=51 | issue=4 | pages=681–694 | doi=10.2307/4119722| jstor=4119722 | bibcode=1996KewBu..51..681B }}</ref><ref>{{cite journal | first=Silmary de Jesus | last= Gonçalves-Alvim |year=2001 | title=Resin-collecting bees (Apidae) on Clusia palmicida (Clusiaceae) in a riparian forest in Brazil | journal=Journal of Tropical Ecology | volume=17 | issue=1 | pages=149–153 | doi=10.1017/s0266467401001092| s2cid= 85842020 }}</ref> [[Propolis]], consisting largely of resins collected from plants such as [[poplars]] and [[conifer]]s, is used by [[honey bee]]s to seal small gaps in their hives, while larger gaps are filled with beeswax.<ref name=Finstrom>{{cite journal|last1=Simone-Finstrom|first1=M.|last2=Spivak|first2=M.|year=2010|title=Propolis and bee health: The natural history and significance of resin use by honey bees|journal=Apidologie|volume=41|issue=3|pages=295–311|doi=10.1051/apido/2010016|s2cid=15828725|url=https://link.springer.com/content/pdf/10.1051/apido/2010016.pdf|doi-access=free}}</ref>