Influence of the Titanium Content in the Ti-MCM-41 Catalyst on the Course of the α-Pinene Isomerization Process

Abstract

Titanium-containing mesoporous silica catalysts with different Ti contents were prepared by the sol–gel method, whereby the molar ratios of silicon to titanium in the crystallization gel amounted to, respectively, 40:1, 30:1, 20:1 and 10:1. The produced Ti-MCM-41 materials were characterized by the following instrumental methods: XRD, UV-Vis, FT-IR, SEM, and XRF. Textural parameters were also determined for these materials by means of the N2 adsorption/desorption method. The activities of these catalysts were investigated in the α-pinene isomerization process. The most active catalyst was found to be the material with the molar ratio of Si:Ti equal to 10:1, which contained 12.09 wt% Ti. This catalyst was used in the extended studies on the α-pinene isomerization process, and the most favorable conditions for this reaction were found to be temperature of 160 °C, reaction time of 7 h, with the catalyst composition of 7.5 wt% relative to α-pinene. These studies showed that the most active catalyst, at the best reaction conditions, allowed for the attainment of 100% conversion of α-pinene over a period of 7 h. After this time the selectivities (in mol%) of the main products were as follows: camphene (35.45) and limonene (21.32). Moreover, other products with lower selectivities were formed: γ-terpinene (4.38), α-terpinene (8.12), terpinolene (11.16), p-cymene (6.61), and α-phellandrene (1.58).

Relationship Between the Pore Structure of Mesoporous Silica Supports and the Activity of Nickel Nanocatalysts in the CO2 Reforming of Methane

“…The discovery of Mobil Crystalline Materials, such as MCM-41 in 1992 by Mobil Oil Corporation scientists [1], has initiated intensive attention in the development of mesoporous silica materials and their applications in research and industry [2][3][4][5][6][7][8][9][10][11][12][13][14]. Afterwards, a range of highly ordered mesoporous silica materials such as SBA-15 and KIT-6 have been created in 1998 and 2003, respectively [15,16].…”

“…A range of approaches has been developed to overcome this obstacle. Optimising the pore size and the development of hierarchical porous materials including different pore size systems have received special attention in recent years [9][10][11][12][13][14]37,38,[40][41][42][43][44][45][46][47][48][49][50][51][52][53]. This is because the hierarchical porous structure of the silica supports can not only increase the mass transport of the reactants to the Ni active sites, but also the mesoporous matrix hinders the thermal sintering of the Ni particles by the confinement effect [24,[54][55][56].…”

Potassium Alum [KAl(SO4)2∙12H2O] solid catalyst for effective and selective methoxylation production of alpha-pinene ether products

“…Turpentine is a valuable and renewable natural resource widely used in the medical industry, for the synthesis of new important chemicals foruse as cosmetic, flavours, fragrances, and pharmaceuticals sectors as well as in the synthesis of chemical intermediates [3]. Thus, α-Pinene is considered a versatile building block for the synthesis of high-value added chemicals, mainly through catalytic processes, such as hydration [4,5,6,7,8,9], isomerization [10,11], epoxidation and pinene oxide isomerization [12,13,14], esterification [15,16], and etherification [17,18,19,20,21,22], among others can be applied to obtain a wide variety of added value products.…”

Role of Brønsted and Lewis acidic sites in sulfonated Zr-MCM-41 for the catalytic reaction of cellulose into 5-hydroxymethyl furfural

“…2 and textural properties were presented in Table 1. For MCM-41, a hysteresis loop has been observed above the relative pressure P/ P 0 = 0.85 [26]. The isotherm curve of MCM-41 was similar to Type-IV with the H1 hysteresis loop of classification of the porous materials by IUPAC [27].…”