The catalytic isomerization reaction of α-pinene to camphene over a clinoptilolite catalyst was investigated in a batch reactor open to the atmosphere between 130 and 155°C. The catalyst was selective to the isomerization of α-pinene to camphene. The effects of several variables, such as reaction temperature, amount of catalyst, stirring speed and catalyst particle size, on the conversion of α-pinene and selectivity to camphene were determined. The reaction fits a first-order parallel reaction with rate constants of k 1 = 3.020·10 −2 e −33381.6/RT for the production of camphene and of k 2 = 1.576·10 −2 e −31096.53/RT for the production of limonene. JAOCS 74, 1145JAOCS 74, -1151JAOCS 74, (1997. KEY WORDS:Camphene, isomerization, kinetics of isomerization of α-pinene, selective catalyst.The purpose of this study was to investigate the effects of several variables, such as reaction temperature, amount of catalyst, stirring speed and catalyst particle size, on the conversion of α-pinene to camphene (X c ), and on the overall selectivity for camphene over an activated clinoptilolite zeolite catalyst, which was found as the most selective after a selectivity screening test. We also wanted to develop a suitable rate equation for the isomerization of α-pinene to camphene.Camphene is an important industrial chemical from which many products of commerce, such as toxaphene, isobornyl acetate, isoborneol, and camphor are made. Comparatively small amounts are used to produce fragrance chemicals by reaction with phenols.Camphene is produced commercially by treatment of α-pinene over acidic catalysts in the absence of water (Scheme 1). It can be produced similarly from β-pinene and from pinene-containing materials, such as gum turpentine, wood turpentine and sulfate turpentine, which are obtained in the manufacture of paper from delignification of wood. Isomerization of α-pinene is generally carried out at reflux temperature in the presence of titania, minerals that contain a specific group of silicates (halloysite, zeolites), or activated clays. Preparation of the catalyst has a great influence on product yields and composition. The chief by-products of the isomerization are tricyclene, which is always obtained with camphene as an equilibrium product, and p-menthadienes.Many one-step methods with catalysts have been suggested in the literature (1) for the preparation of camphene. Various types of catalysts, both organic and inorganic, as well as mineral, have been reported to promote the isomerization of pinene directly to camphene. The catalysts must be treated with an acid to activate the surface. The time for complete conversion of the terpene being isomerized varies with the nature and amount of the catalyst used and the temperature employed. Carson (2) used chlorites, and Kirkpatrick (3) tried halloysite as catalyst for the isomerization of pinene to camphene and obtained a yield of 60% by weight. Korotov et al.(4) prepared camphene by isomerization of pinene in the presence of TiO 2 . Afanas'eva and coworkers (5,6) st...

In this work, ultrasonic degradation of acetic acid, which is one of the most resistant carboxylic acids to oxidize, was investigated. The effects of parameters such as ultrasonic power, initial concentration, addition of NaCl or several oxides were studied on the degradation of acetic acid. Acetic acid was sonicated indirectly using an ultrasonic bath with 40 kHz. It was observed that degradation degree increased with decreasing power and initial concentration and with increasing NaCl concentration. Initial degradation degree was enhanced with addition of zeolite and SiO(2).

Sonochemical oxidation has a promising future in the area of waste water treatment as one of the advanced oxidation methods. In this study, direct ultrasonic degradation of acetic acid was investigated in low powers (0.1-0.4 W) and in a frequency range of 30-100 kHz. An ultrasonic transducer was used for sonication. The results showed that there was an optimum frequency at 60 kHz for direct sonication of acetic acid and degradation rate increased up to a power of 0.2 W and then it decreased. Sonochemistry is associated with the bubble of cavitation which depends on the sound pressure field and nature of molecule. Therefore, the frequency and intensity have to be optimized for the minimization of energy requirement during waste water treatment with ultrasound.

Ultrasonic irradiation is one of the advanced oxidation methods used in wastewater treatment. In this study, ultrasonic treatment of petroleum refinery effluent was examined. An ultrasonic homogenizator with a 20 kHz frequency and an ultrasonic bath with a 42 kHz frequency were used as a source for ultrasound. The effects of parameters such as ZnO amount, ozone saturation time, and type of ultrasound source on the degradation of petroleum refinery effluent were investigated. The degradation of petroleum refinery effluent was measured as a change in initial chemical oxygen demand (COD) and with time. According to the results, degradation increased with the addition of ZnO in an ultrasonic probe. There was also a positive effect of ozone saturation before sonication then applying ultrasound on the degradation for an ultrasonic probe. It was observed that there was no positive effect of ZnO addition and ozone saturation on degradation for an ultrasonic bath.

Baker's yeast effluent is a major source of pollution with a high organic load and dark colour. It can be treated by using advanced oxidation processes (AOPs). AOPs, such as ultrasonic irradiation, are ambient temperature processes involving the generation of free radicals. We have investigated sonocatalytic treatment of baker's yeast effluent by using ultrasound. TiO 2 -ZnO composites were used as sonocatalysts to increase the efficiency of the ultrasonic irradiation. The TiO 2 /ZnO composite was prepared by two different methods. Ultrasonic irradiation or mechanical stirring was used to prepare the TiO 2 -ZnO composite, and an ultrasonic homogenizer with a 20 kHz frequency was used to treat the baker's yeast effluent. We studied the effects of several parameters, including the molar ratio of TiO 2 /ZnO, calcination temperature, calcination time and catalyst amount, on the sonocatalytic treatment of the effluent.According to the results, the decolorization rate was 25% when using the composite TiO 2 /ZnO prepared at a 4:1 molar ratio and treated at 700 W C for 60 min, and the optimum catalyst amount was 0.15 g/l.