ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTCatalytic Upgrading of Extractives to Chemicals: Monoterpenes to "EXICALS"Mikhail Golets*†, Samikannu Ajaikumar‡, and Jyri-Pekka Mikkola*†‡View Author Information† Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FI-20500 Åbo-Turku, Finland‡ Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University, SE-90187 Umeå, Sweden*E-mail: [email protected]. Tel.: +46 0 76 104 3381.*E-mail: [email protected]. Tel. +46 0 70 620 0371.Cite this: Chem. Rev. 2015, 115, 9, 3141–3169Publication Date (Web):April 23, 2015Publication History Received30 July 2014Published online23 April 2015Published inissue 13 May 2015https://pubs.acs.org/doi/10.1021/cr500407mhttps://doi.org/10.1021/cr500407mreview-articleACS PublicationsCopyright © 2015 American Chemical SocietyRequest reuse permissionsArticle Views2263Altmetric-Citations78LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Catalysts,Isomerization,Organic reactions,Oxides,Selectivity Get e-Alerts

Mesostructured siliceous SBA-15 was synthesized via direct hydrothermal crystallization from acidic solution of poly-(ethylene glycol)-block-poly(propylene glycol)-block poly(ethylene glycol)-copolymer and tetraethyl orthosilicate. The amorphous surface of the calcined Si-SBA-15 was modified with 20wt.% of TiO2 by chemical grafting method using titanium isopropoxide as the titanium source in ethanol solution. Various metal nanoparticles Au, Au–M (M=Co, Ni, Cu and Zn) were supported on TiO2/SBA-15 by deposition–precipitation method (DP) using urea as the precipitating agent. The structural features of the synthesized materials were characterized by various physico-chemical techniques such as X-ray diffraction, nitrogen physisorption (BET), XPS and HR-TEM. BET results of Si-SBA-15 revealed the formation of mesoporous structure with an average pore size of 5.9nm, pore volume of 1.12cm3/g and the specific surface area of 846m2/g. HR-TEM results demonstrated that metal nanoparticles were highly dispersed over TiO2/SBA-15 and long range ordering of hexagonal mesopores of Si-SBA-15 was well retained after loading of 20wt.% TiO2 and 3wt.% of bimetallic nanoparticles. The catalytic performances of the prepared catalysts were studied on dehydroisomerization of α-pinene under gas phase conditions using hydrogen atmosphere. The stability and catalytic activity of Au–M–TiO2/SBA-15 (DP) catalysts upon conversion of α-pinene into p-cymene was explored in comparison with the catalysts prepared by conventional method. AuNi–TiO2/SBA-15 catalysts prepared via DP method were found to be stable upon longer reaction time as well as superior in terms of conversion and selective towards the formation of p-cymene.

The aim of this work was to demonstrate the feasibility to produce rho-cymene, an important commodity chemical, in a continuous, one-pot reaction system from abundant alpha-pinene, available e.g. as a by-product of pulping industry. The isomerization reactions of alpha-pinene over bimetallic heterogeneous catalysts, 3 and 5 wt% Pd-Zn (1:1, 1:4, 4:1, 1:0, and 0:1), supported on Al-SBA15 were studied. The principal reaction products were identified as rho- and m-cymenes, limonene, camphene, and rho-menthene, respectively. The highest concentration of rho-cymene reached 77 wt% under the optimized reaction conditions: 300 degrees C and alpha-pinene feed of 0.03 mL/min. Two main reaction pathways toward rho- and m-cymenes were described, and a mechanistic kinetic model, based on a plausible reaction network in line with Langmuir-Hinshelwood approach, was developed. The catalyst characterization revealed the reduction in Pd(II) sites, catalyst coking, and decline of surface area over the course of time. The catalyst recovery and reuse was addressed. (C) 2013 Elsevier Inc. All rights reserved.

The effective dispersion of active metal species on mesoporous Si-SBA-15 is acquired by means of deposition-precipitation method. In order to achieve this, the surface of Si-SBA-15 was first modif ...

The present study introduces kinetic modeling of liquid phase α-pinene acetoxylation with acetic acid over an ion-exchange resin catalyst. The reaction was carried out in a laboratory scale high-pressure autoclave. α-terpinyl (35 wt%) and bornyl (40 wt%) acetates were the primary products. The predominant reaction pathways were identified and evaluated.

Heterogeneously-catalyzed and solvent-catalyzed liquid phase acetoxylation of alpha-pinene with acetic acid acting as both a solvent and a reagent was studied. Both solvent-catalyzed and catalytic experiments were carried out and various reaction conditions were studied. The influence of temperature, pressure, solvent and gas milieu were taken into account. Bornyl, fenchyl, verbenyl as well as alpha-terpinyl acetates, limonene, camphene and gamma-terpinene were found among reaction products. The addition of the catalyst allowed for maximization of the yield of bornyl acetate. The predominant products obtained were alpha-terpinyl, verbenyl and bornyl acetates. The reaction pathways were identified and evaluated.The aim of this work was to study the feasibility of batch acetoxylation of a-pinene. The analysis of the complex product distribution is not trivial and, consequently, resolving the reaction network was important. The optimized reaction conditions were searched for aiming at an efficient conversion of alpha-pinene to a mixture of valuable products. (c) 2012 Elsevier B.V. All rights reserved.