The catalytic coconversion of glycerol and toluene (93/7 wt %) over a technical H-ZSM-5/Al2O3 (60-40 wt %) catalyst was studied, aiming for enhanced production of biobased benzene, toluene, and xylenes (bio-BTX). When using glycerol/toluene cofeed with a mass ratio of 93/7 wt %, a peak BTX carbon yield of 29.7 ± 1.1 C.% (at time on stream (TOS) of 1.5-2.5 h), and an overall BTX carbon yield of 28.7 C.% (during TOS of 8.5 h) were obtained, which are considerably higher than those (19.1 ± 0.4 C.% and 11.0 C.%) for glycerol alone. Synergetic effects when cofeeding toluene on the peak and overall BTX carbon yields were observed and quantified, showing a relative increase of 3.1% and 30.0% for the peak and overall BTX carbon yield (based on the feedstock). These findings indicate that the strategy of cofeeding in situ produced toluene for the conversion of glycerol to aromatics has potential to increase BTX yields. In addition, BTX production on the catalyst (based on the fresh catalyst during the first run for TOS of 8.5 h and without regeneration) is significantly improved to 0.547 ton ton-1catalyst (excluding the 76% of toluene product that is 0.595 ton ton-1catalyst for the recycle in the cofeed) for glycerol/toluene cofeed, which was 0.426 ton ton-1catalyst for glycerol alone. In particular, this self-sufficient toluene product recycling strategy is advantageous for the production and selectivity (relative increase of 84.4% and 43.5% during TOS of 8.5 h) of biobased xylenes.
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Catalytic pyrolysis of crude glycerol over a shaped H-ZSM-5 zeolite catalyst with (partial) recycling of the product oil was studied with the incentive to improve benzene, toluene, and xylene (BTX) yields. Recycling of the polycyclic aromatic hydrocarbon (PAH) fraction, after separation from BTX by distillation and co-feeding with the crude glycerol feed, was shown to have a positive effect on the BTX yield. Further improvements were achieved by hydrogenation of the PAH fraction using a Ru/C catalyst and hydrogen gas prior to co-pyrolysis, and BTX yields up to 16 wt% on feed were obtained. The concept was also shown to be beneficial to other biomass feeds such as e.g., Kraft lignin, cellulose, and Jatropha oil.
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The present invention relates to a novel process for the preparation of low molecular weight aromatic compounds such as benzene, toluene, and xylenes (BTX) from plastics. Provided is a thermo-catalytic pyrolysis process for the preparation of aromatic compounds from a feed stream comprising plastic, comprising the steps of: a) subjecting a feed stream comprising a plastic to a pyrolysis treatment at a pyrolysis temperature in the range of 600-1000°C to produce pyrolysis vapors; b) optionally cooling the pyrolysis vapors to a temperature that is below the pyrolysis temperature; c) contacting the vaporous phase with an aromatization catalyst at an aromatization temperature in the range of 450 - 700 °C, which aromatization temperature is at least 50°C lower than the pyrolysis temperature, in a catalytic conversion step to yield a conversion product comprising aromatic compounds; and d) optionally recovering the aromatic compounds from the conversion product.
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Article Evaluation of a Commercial Electronic Nose Based on Carbon Nanotube Chemiresistors
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Implementation of reliable methodologies allowing Reduction, Refinement, and Replacement (3Rs) of animal testing is a process that takes several decades and is still not complete. Reliable methods are essential for regulatory hazard assessment of chemicals where differences in test protocol can influence the test outcomes and thus affect the confidence in the predictive value of the organisms used as an alternative for mammals. Although test guidelines are common for mammalian studies, they are scarce for non-vertebrate organisms that would allow for the 3Rs of animal testing. Here, we present a set of 30 reporting criteria as the basis for such a guideline for Developmental and Reproductive Toxicology (DART) testing in the nematode Caenorhabditis elegans. Small organisms like C. elegans are upcoming in new approach methodologies for hazard assessment; thus, reliable and robust test protocols are urgently needed. A literature assessment of the fulfilment of the reporting criteria demonstrates that although studies describe methodological details, essential information such as compound purity and lot/batch number or type of container is often not reported. The formulated set of reporting criteria for C. elegans testing can be used by (i) researchers to describe essential experimental details (ii) data scientists that aggregate information to assess data quality and include data in aggregated databases (iii) regulators to assess study data for inclusion in regulatory hazard assessment of chemicals.
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For the recycling of carpet and artificial turf the latex backing is often a real stumble block. Many strategies have been developed like freezing the carpet, followed by grinding and subsequent separation of the milled particles. Once it has been separated from its backing materials, PA 6 is relatively easy to depolymerise. This produces fresh caprolactam that can be used to manufacture PA 6 with no loss in quality, and is suitable for further recycling [1]. The comparable process for PA 6,6 is not as easy, but DuPont and Polyamid 2000 have developed and patented a process that depolymerises any mixture of PA 6 and 6,6 using ammonia. The result is fresh caprolactam and 1,6 diaminohexane for manufacture of PA 6 and 6,6 respectively [2]. Obviously a lot of research has been devoted to avoiding latex as a backing like e.g. polyurethane carpet backing systems based on natural oil polyols and polymer polyols [4]. Still carboxylated styrene butadiene is the leading synthetic latex polymer used in EU-27 for carpet backing, followed by styrene-acrylics and pure acrylics. This contrasts with Eastern Europe, Russia, and Turkey where styrene-acrylics dominate, followed by PVAc and redispersible powders [3]. In addition there has been a lot of research into developing alternative backing systems where the backing can easily be removed. Examples are the use of gecko technology [5] or using click chemistry (reversible Diels Alder reactions) [6]. But the best option for recycling is of course to develop carpets based completely on monomaterials. Paper for the 14th Autex World Textile Conference May 26th-28th 2014, Bursa, Turkey.
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Inhibition of the sodium−glucose cotransporter 2 (SGLT2) by canagliflozin in type 2 diabetes mellitus results in large between-patient variability in clinical response. To better understand this variability, the positron emission tomography (PET) tracer [18F]canagliflozin was developed via a Cu-mediated 18F-fluorination of its boronic ester precursor with a radiochemical yield of 2.0 ± 1.9% and a purity of >95%. The GMP automated synthesis originated [18F]canagliflozin with a yield of 0.5−3% (n = 4) and a purity of >95%. Autoradiography showed [18F]canagliflozin binding in human kidney sections containing SGLT2. Since [18F]canagliflozin is the isotopologue of the extensively characterized drug canagliflozin and thus shares its toxicological and pharmacological characteristics, it enables its immediate use in patients.
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tmoA and related genes encode the alpha-subunit of the hydroxylase component of the major group (subgroup 1 of subfamily 2) of bacterial multicomponent mono-oxygenase enzyme complexes involved in aerobic benzene, toluene, ethylbenzene and xylene (BTEX) degradation. A PCR-denaturing gradient gel electrophoresis (DGGE) method was developed to assess the diversity of tmoA-like gene sequences in environmental samples using a newly designed moderately degenerate primer set suitable for that purpose. In 35 BTEX-degrading bacterial strains isolated from a hydrocarbon polluted aquifer, tmoA-like genes were only detected in two o-xylene degraders and were identical to the touA gene of Pseudomonas stutzeri OX1. The diversity of tmoA-like genes was examined in DNA extracts from contaminated and non-contaminated subsurface samples at a site containing a BTEX-contaminated groundwater plume. Differences in DGGE patterns were observed between strongly contaminated, less contaminated and non-contaminated samples and between different depths, suggesting that the diversity of tmoA-like genes was determined by environmental conditions including the contamination level. Phylogenetic analysis of the protein sequences deduced from the amplified amplicons showed that the diversity of TmoA-analogues in the environment is larger than suggested from described TmoA-analogues from cultured isolates, which was translated in the DGGE patterns. Although different positions on the DGGE gel can correspond to closely related TmoA-proteins, relationships could be noticed between the position of tmoA-like amplicons in the DGGE profile and the phylogenetic position of the deduced protein sequence.
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Active antifungal packaging is a technological solution for reducing the postharvest losses of fruits and vegetables associated with phytopathogens. Anthracnose (Colletotrichum gloeosporioides) is the principal fungus that causes post-harvest avocado fruit decay. In this study, antifungal sachets filled with oregano oil-starch capsules were prepared, and their active effects were demonstrated on Hass avocado fruits. Oregano oil (31 % of carvacrol) was encapsulated with corn starch by spray drying. Tyvek sachets (4 × 4 cm) filled with 80 (T1) and 160 mg (T2) of oregano oil-starch capsules (99.35 ± 1.86 mg g − 1) were fabricated. The antifungal effects of the sachets were tested in vitro and in vivo using a humidity chamber (90–95 % relative humidity (RH)) on fruits inoculated with anthracnose. The results showed that T1 and T2 inhibited 75.21 ± 2.81 and 100 % in vitro growth of anthracnose at 25 °C for 12 days. Furthermore, Hass avocado fruits stored in a humidity chamber at 25 °C for 6 days showed that only T2 significantly (p < 0.05) reduced the area of lesion produced by artificial inoculation of Hass avocado fruits with anthracnose. On average, the lesion area in the Hass avocado fruits treated with T2 was 13.94 % smaller than that in the control fruit.
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