The use of gas chromatography coupled with mass spectrometry (GC-MS) for identification of fine chemicals

Introduction Controlled partial oxidation of natural products, such as terpenes, is one of the most important technologies to obtain cosmetic ingredients. For economic reasons, these processes mainly involve the use of molecular oxygen as the primary oxidant. Their success depends mostly on the use of a catalyst containing metal species in order to promote both the rate of reaction and the selectivity to partially oxidated products [1]. Both homogeneous and heterogeneous catalysts have been tested for this purpose over the last few decades [2]. The positive contribution of heterogeneous catalysis to fine chemistry is related to the characteristics role of the catalyst, i.e. [3]: to specifically activate a selected functionality; to make a • chemical reaction more efficient, faster and more selective, and thus, to lower the raw material costs and/or increase the productivity to allow certain transformations to new molecular structures • which are otherwise low-yielding, or even impossible by classical means. This often allows spectacular shortcuts through the synthetic pathways to have obvious ecological advantages, whenever the use of • stoichiometric amounts of sometimes hazardous reagents can be avoided. In this context, the use of heterogeneous catalysis in the liquid phase reactions towards the production of large amounts of chemicals is an obvious ambitious objective. A wide variety of terpenes make a renewable, sustainable feedstock for the fine chemical industry [4]. These compounds are plentiful in the nature, i.e. in spice oils, citrus oils, pine oils and other natural products. Terpenes are an important source of ingredients and intermediates for flavors and fragrances and vitamins (e.g. A and E) [1]. The main structures of terpenes, which are used in the cosmetic manufacture are shown in Figure 1. Catalytic transformations of terpenes are well documented [4 ,6, 7], comprising a wide variety of reactions: oxidation, hydrogenation, dehydrogenation, hydroformylation, hydration, carbonylation and etc. Terpenes can also be converted to the corresponding epoxides by reactions with hydrogen peroxide in the presence of various catalysts. In our work we used mesoporous materials as catalysts. In this study we would like to test the activity of niobium species in epoxidation reactions of some terpenes using heterogeneous catalysts, i.e., mesoporous materials containing niobium and an environmentally friendly oxidant – hydrogen peroxide. Moreover, as the non-toxicity, of course, is a conditio sine qua non, thus the one-pot synthesis of Nb–type mesoporous materials was carried out using low cost and biodegradable surfactants as structure directing agents. The synthesis of mesoporous materials is mostly related with “building mesopores” [8]. Mesoporous molecular sieves are obtained from the organic inorganic assembly by using soft matter that is organic molecules or supramolecules (e.g., surfactants). Nonionic surfactants are accessible in a wide variety of different chemical structures. They are extensively used in industry because of attractive characteristics like low price, nontoxicity, and biodegradability [e.g. 9]. One of them is the SBA-15 porous structure that represents a 2D hexagonally organized network. The open frameworks and tunable porosities endow mesoporous materials with accessibility to chemical reagents, so these characteristics are really important in the field of catalysis.