Pinenes

Further, the hydrocarbon nature of rosin structures imparts an excellent hydrophobicity to the PCL with a contact angle closely to that of poly(styrene) thus effecting a very low water absorption. The graft copolymers maintain the full degradability and a good biocompatibiUty. 

The addition of thiols to terpenes, e.g., limonene and pinene have been studied (3). This is a simple approach to synthesize a wide range of alcohol or ester functionalized renewable monomers. The endocycUc and exocyclic double bonds of the limonene monomers exhibit different reactivities. By a variation of the thiol feed ratio monoaddition or diaddition products can be obtained. Similarity, pinene derivates can be prepared. 

Long-chain diesters an diols, using castor oil have been synthesized (3). These are suitable comonomers that give in polycondensates with a number average molecular weights of up to 25 k D. 

Pinenes are the most interesting because they can be easily isolated by steam-distiUation from the resins of coniferous trees. 

By isomerization into the a- form and optionally some further functionalization, these modified pinenes may rmdergo a common cationic pol5mierization (4). 

---

Borneol and isoboineol are respectively the endo and exo forms of the alcohol. Borneol can be prepared by reduction of camphor inactive borneol is also obtained by the acid hydration of pinene or camphene. Borneol has a smell like camphor. The m.p. of the optically active forms is 208-5 C but the racemic form has m.p. 210-5 C. Oxidized to camphor, dehydrated to camphene. 

Ordinary commercial camphor is (-i-)-cam phor, from the wood of the camphor tree. Cinnamonum camphora. Camphor is of great technical importance, being used in the manufacture of celluloid and explosives, and for medical purposes, /t is manufactured from pinene through bornyl chloride to camphene, which is either directly oxidized to camphor or is hydrated to isoborneol, which is then oxidized to camphor. A large number of camphor derivatives have been prepared, including halogen, nitro and hydroxy derivatives and sulphonic acids. 

C, b.p. 156 C. The most important of the terpene hydrocarbons. It is found in most essential oils derived from the Coniferae, and is the main constituent of turpentine oil. Contains two asymmetric carbon atoms. The (- -)-form is easily obtained in a pure state by fractionation of Greek turpentine oil, of which it constitutes 95%. Pinene may be separated from turpentine oil in the form of its crystalline nitrosochloride, CioHigClNO, from which the ( + )-form may be recovered by boiling with aniline in alcoholic solution. When heated under pressure at 250-270 C, a-pinene is converted into dipentene. It can be reduced by hydrogen in the presence of a catalyst to form... 

First wash with a volume of Glacial Acetic Acid equal to the amount of Sassafras Oil being processed. This will remove Euge-nol, Pinene and Camphor from the oil. 

Using 28% acetic acid allows the eugenol, d-camphor and pinene to form its own top layer. There ivas no separation using 99.5% acetic acid. 

Various terminal allylic compounds are converted into l-alkenes at room temperature[362]. Regioselective hydrogenolysis with formate is used for the formation of an exo-methylene group from cyclic allylic compounds by the formal anti thermodynamic isomerization of internal double bonds to the exocyclic position[380]. Selective conversion of myrtenyl formate (579) into /9-pinene is an example. The allylic sulfone 580 and the allylic nitro compound... 

In practice hydrogenation of a pinene is observed to be 100% stereoselective The only product obtained is cis pinane No trans pinane is formed... 

Hydroboration-oxidation of a pinene (page 235) like catalytic IS stereoselective Addition takes place at the less hindered face and a single alcohol is produced in high yield (89%) Sug... 

---