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Dimethyl terephthalate

About: Dimethyl terephthalate is a research topic. Over the lifetime, 1234 publications have been published within this topic receiving 13069 citations.


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Journal ArticleDOI
TL;DR: Isolated atoms of noble metals in low oxidation states, appropriately complexed and tethered to the inner walls of nanoporous (ca. 3 nm diameter) silica, are very promising enantioselective hydrogenation catalysts.
Abstract: Bimetallic nanoparticles (Ru6Pd6, Ru6Sn, Ru10Pt2, Ru5Pt, Ru12Cu4, and Ru12Ag4) anchored within silica nanopores exhibit high activities and frequently high selectivities, depending upon the composition of the nanocatalyst, in a number of single-step (and often solvent-free) hydrogenations at low temperatures (333−373 K). The selective hydrogenations of polyenes (such as 1,5,9-cyclododecatriene and 2,5-norbornadiene) are especially efficient. Good performance is found with these nanoparticle catalysts in the hydrogenation of dimethyl terephthalate to 1,4 cyclohexanedimethanol and of benzoic acid to cyclohexanecarboxylic acid or to cyclohexene-1-carboxylic acid, and also in the conversion of benzene to cyclohexene (or cyclohexane), the latter being an increasingly important reaction in the context of the production of Nylon. Isolated atoms of noble metals (Pd, Rh, and Pt) in low oxidation states, appropriately complexed and tethered to the inner walls of nanoporous (ca. 3 nm diameter) silica, are very promi...

549 citations

Journal ArticleDOI
TL;DR: In this article, the authors showed that a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed when Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Bronsted acid containing zeolites (Al-Beta), are used as catalysts.
Abstract: Terephthalic acid (PTA), a monomer in the synthesis of polyethylene terephthalate (PET), is obtained by the oxidation of petroleum-derived p-xylene. There is significant interest in the synthesis of renewable, biomass-derived PTA. Here, routes to PTA starting from oxidized products of 5-hydroxymethylfurfural (HMF) that can be produced from biomass are reported. These routes involve Diels-Alder reactions with ethylene and avoid the hydrogenation of HMF to 2,5-dimethylfuran. Oxidized derivatives of HMF are reacted with ethylene over solid Lewis acid catalysts that do not contain strong Bronsted acids to synthesize intermediates of PTA and its equally important diester, dimethyl terephthalate (DMT). The partially oxidized HMF, 5-(hydroxymethyl)furoic acid (HMFA), is reacted with high pressure ethylene over a pure-silica molecular sieve containing framework tin (Sn-Beta) to produce the Diels-Alder dehydration product, 4-(hydroxymethyl)benzoic acid (HMBA), with 31% selectivity at 61% HMFA conversion after 6 h at 190 °C. If HMFA is protected with methanol to form methyl 5-(methoxymethyl)furan-2-carboxylate (MMFC), MMFC can react with ethylene in the presence of Sn-Beta for 2 h to produce methyl 4-(methoxymethyl)benzenecarboxylate (MMBC) with 46% selectivity at 28% MMFC conversion or in the presence of a pure-silica molecular sieve containing framework zirconium (Zr-Beta) for 6 h to produce MMBC with 81% selectivity at 26% MMFC conversion. HMBA and MMBC can then be oxidized to produce PTA and DMT, respectively. When Lewis acid containing mesoporous silica (MCM-41) and amorphous silica, or Bronsted acid containing zeolites (Al-Beta), are used as catalysts, a significant decrease in selectivity/yield of the Diels-Alder dehydration product is observed.

236 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the rate of methanolysis strongly depends on the solubility of polyethylene terephthalate (PET) and that the depolymerization took place at random positions on the polymer chain.

173 citations

Journal ArticleDOI
TL;DR: In this paper, a simple theoretical model was developed to describe the hydrolysis rate of polyethylene terephthalate (PET) from postconsumer soft-drink bottles.
Abstract: Poly(ethylene terephthalate) (PET) taken from postconsumer soft-drink bottles was subjected to alkaline hydrolysis after cutting it into small pieces (flakes). The reaction took place in an autoclave at 120–200°C with aqueous NaOH solutions and at 110–120°C with a nonaqueous solution of KOH in methyl Cellosolve. The disodium or dipotassium terephthalate received was treated with sulfuric acid and terephthalic acid (TPA) of high purity was separated. The 1H NMR spectrum of the TPA revealed an about 2% admixture of isophthalic acid together with the pure 98% TPA. The purity of the TPA obtained was tested by determining its acidity and by polymerizing it with ethylene glycol by using tetrabutyl titanate as catalyst. A simple theoretical model was developed to describe the hydrolysis rate. The activation energy calculated was 99 kJ/mol. This method is very useful in recycling of PET bottles and other containers because nowadays TPA is replacing dimethyl terephthalate (the traditional monomer) as the main monomer in the industrial production of PET. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 250–259, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10029

162 citations

Journal ArticleDOI
TL;DR: In this article, Nanoparticles of both Ru5Pt and Ru10Pt2, uniformly distributed along the inner walls of mesoporous silica, exhibit high catalytic performance in the single-step hydrogenation of dimethyl terephthalate (DMT), to 1,4-cyclohexanedimethanol (CHDM); see scheme.
Abstract: Pores for cluster catalysts: Nanoparticles of both Ru5Pt and Ru10Pt2, uniformly distributed along the inner walls of mesoporous silica, exhibit high catalytic performance in the single-step hydrogenation of dimethyl terephthalate (DMT, to 1,4-cyclohexanedimethanol (CHDM); see scheme), of benzoic acid (to cyclohexane carboxylic acid), and of naphthalene (in the presence of sulfur) to cisdecalin.

159 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20236
202216
202110
202021
201925
201832