Turpentine oil and Rosin

i thought this warrented a new thread as it was off-topic where i first posted it. and wanted to add a few bits.


Quote:
Originally Posted by ziggy searchfield
I stand corrected

19th Century Historical Tidbits: Turpentine Making


thanks for that link Ziggy, enjoyed reading it.

from a modern day perspective turpentine oil production is a whole different ball game.

firstly it is a by-product from the paper industry; when the wood pulp slurry is pressed into paper the crude "venetian" turpentine separates to the surface on the water. (usually a pale gold yellow oil) this is then taken and dry distilled under vacuum, the distillate being turpentine oil and the residue being rosin (sometimes known as colophony) a gold to amber glass like resin.

secondly, nowadays, we only see turpentine substitute for DIY purposes (which is a derived fraction of fossil fuel oil) because the turpentine oil itself has much more value in other industries, predominantly in perfumes.

the major component of turpentine oil is alpha-pinene which can be isomerised into beta-pinene, both of which are used in thier own right in perfumery, but, more importantly are the down-stream products from them such as ionones, longifolenes, terpineols, linalool, geraniol. nerol, citronellol, citral... the list is enormous and new derivatives are created each year. they all end up in our chanel no5s, washing up liquids, air fresheners et al.

rosin, well "rosin up his bow" as any violinist will attest to is applying powdered rosin to the hair on the bow to aid friction with the strings as (depending on how hard the crude turpentine has been distilled to residue) gets a little sticky on warming. another use of rosin was (and possibly still is, im not sure) the base for road markings as its softening temperature is close to that of tarmac. historically rosin was also used to adulterate benzoin and tolu resins, since both are used in flavours and rosin is banned a simple test with copper II acetate instantly reveals its presence. (incedentally the outside appearance of the shell of a certain brand of mini eggs is due to a dip in an alcohollic solution of benzoin, its an improvement i suppose, considering, at one time it was shellac!)

apologies, i have rambled a bit there.

Herbi