Pinene isomerization

The /3-pinene fraction was used as a reference to determine the isomerization activity of the supports. Results given in Table 4 show that carbon VII is particularly inert with respect to /3-pinene. This behaviour is certainly related to the high content of this carbon in potassium (0.5 wt.-%). On the contrary, the CaO impurities present in carbon V seem to increase the isomerization activity of this carbon. It is well-known that the double bond shift isomerization of hydrocarbons can proceed via carbocation intermediates (protonic catalysis) or via allylic carbanion intermediates (acido-basic or purely basic catalysis) [Ref.7]. The results obtained with potassium-doped carbons show that in /3-pinene isomerization during HDS, the protonic mechanism predominates. 

Our plans also included the exploration of the fundamentals of this copdymer-ization in which one of the monomers, P-pinene, isomerizes prior to propagation. In this sense, this research concerned the investigation of an isomerization copolymerization , a field that has not yet been explored. This phase of our work involved the elucidation of the effect of a variety of initiating systems (counter-ions), solvents, and temperatures on the reactivity ratios of these monomers, on the rate of polymerization, and on the molecular we ts of the products. 

For instance, in the case of a-pinene isomerization over a natural zeolite (Figure 7.3) it was observed that selectivity is independent of temperature or catalyst pretreatment. Therefore, the selectivity analysis was carried out separately from the numerical treatment of activity. 

Figure 7.3. Scheme of a-pinene isomerization (A.I. Allahverdiev, S. Irandoust, D.Yu.Murzin, Isomerisation of a-pinene over clinoptilolite. J.Catal. 185 (1999) 352). 

The system of differential equations describing a-pinene isomerization can be written in the following form... 

Finding a modei Fig, 1 shows experimental data of a-pinene isomerization at 150° C catalysed by 4% of titanium oxide catalyst (conditions 15 % H2SO4, activation temperature, 135 C activation time, 4 hrs). In this figure the concentrations of some species are lumped together in the way described below. 

Figure 4. a-Pinene isomerization. Lumping according to scheme I. 1, a-pinene 2, camphene 3, bor-nylene 4, a-fenchene 5, tricyclene 6, dipentene 7, terpinolene 8, a-terpinene 9, y-terpinene 10, a-phellandrene. 

In [138] a number of siliea- and alumina-supported Ln203 samples are investigated by means of TPD of ehemisorbed CO2 and pyridine, FTIR of adsorbed pyridine, as well as eatalytie assays of a-pinene isomerization and 2-butanol decomposition. Particular attention is paid to the supported ytterbia systems. In good agreement with the results commented on above, supported rare earth oxide systems... 

It is known that specialized computer software have been created for solution of different types of kinetic problems. For example, one can find a specialized software suite Dynafit that is capable of solving inverse kinetic problems. Surely, the developers of such programs usually include some tests or sample files to demonstrate advantages of their products. In particular, a real kinetic problem of a-pinene isomerization is given as one of the examples in a Dynafit tutorial. 

Solkina et al. [10] studied a-pinene isomerization in a fixed bed reactor and used... 

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