Photo-sensitized Oxidation Of β-pinene And Catalyzed Alteration

β-pinene,one of vital monoterpenes which exists in abies oil,can be used as original material from which a series of flavors and perfume intermediates are produced. In this article, photo-sensitized oxidation and catalyzed photo- sensitized oxidation of β-pinene are studied so as to explore new paths on synthesis of myrtenal,myrtenol, β-pinene-2-ol, 3 -pinene-2-one. In the water-welled reactor containing β-pinene, photo-sensitizer,solvent,catalysts,and so on, reaction preceeds with the influx of oxygen in the condition of high-pressure sodium lamp .Analyzing products' components by capillary column GC instrument and identifying their structures by GS-MS,IR,UV/VIS,and 'HNMR, conduct the regular influence of photo source, photo-sensitizer, catalysts,reactional condictions,and so on,on catalyzed photo-sensitized oxidation of β -pinene. 1. photo-sensitized oxidation of β-pineneEmploying high-pressure sodium lamp as photo source, RB as photo-sensitizer in methyl alcohol solvent, the conversion of β-pinene is 63.2%.While the selectivity of myrtenal and myrtenol is 33.1% and 25.5% by RB,that is 17.9% and 9.9%by MB and is less than 10% with a conversion of no more than 40% respectively by fluorescein, eosin B, rosolic acid, benzophenone, 4-methyl-diphenylketone.In the acetic oxide solvent,excitedly, the conversion of material exceeds 92% , and the selectivity of myrtenal amounts to 49.9% with the same photo source and sensitizer.Result ,however, shows a bad reactional activity with a conversion of below 30% and with a selectivity of every product lower than 10% applying high-pressure mercury lamp and 254nm vitalight lamp as photo sources.2. The catalytic effect of transition metals oxides on photosensitized oxidation of β-pinene.As sensitized by RB in methyl alcohol and catalyzed by MoO3,TiO2,ZnO, while the selectivity of oxidative product is either higher or lower, the conversion of β-pinene increases with the protraction and amounts to 82.7%,72.7%,and 80.6%, respectively,for 10 hours using high-pressure sodium lamp as photo source.3. Efficient conversion of β -pinene in the presence of pyridine-acetic oxide.Adding 6% pyridine and 80% acetic oxide to acenitrile solvent of RB, 95.0% conversion of ?-pinene and 65.5% selectivity of myrtenal ,a more satisfactory result,occurs to me at the oxygen influx of 20 ml/min at 288K for 4 hours in high-pressure sodium light .Futher more, if at at 305K, a higher temperature, after 4 hours, that goes up to 93.4% and 85.7%,respectively.Besides that , with the increase of oxygen influx ,while the former goes up then down, the later ascends orderly.In addition, we find that , at the ratio of 6:0,6:40,and 6:80 of pyridine vs acetic oxide, the conversion of β -pinene increases from 82.5% to 82.3% and then to 87.0%, and spontaneously , the selectivity of myrtenal rises from 30.5% to 37.2%, ultimately to 69.5%.