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Advances in Refining Technologies
Published in Deniz Uner, Advances in Refining Catalysis, 2017
James E. Rekoske, Hayim Abrevaya, Jeffery C. Bricker, Xin Zhu, Maureen Bricker
Sulfiding is accomplished mainly in situ, though some refiners have started to do the activation outside the unit (ex situ). More and more refiners will opt to receive the catalyst at the refinery site in pre-sulfided state to accelerate the start-up of the unit. In situ sulfiding can be accomplished either in vapor or liquid phase. In vapor phase sulfiding, the activation of the catalyst is accomplished by injecting a chemical that easily decomposes to H2S, such as dimethyl-disulfide (DMDS) or di-methyl-sulfide (DMS).
Changes in the morphometric, textural, and aromatic characteristics of shiitake mushrooms during combined humid-convective drying
Published in Drying Technology, 2021
Shankar Subramaniam, Xin-Yao Wen, Zhen-Tao Zhang, Pu Jing
Mushrooms are preferred by consumers primarily for their unique aroma. The GC × GC, two-dimensional TIC is depicted in Figure A1. More compounds were present in dried samples than in fresh ones. Supplementary material Table A1 depicts a list of 51 significant volatile compounds which are predominantly responsible for characteristic shiitake aroma. They were compared among 3 samples—fresh, HAD, and CHCD. The peak area of compounds is given relative to the peak area of internal standard (Undecanol-1). CHCD samples showed larger peak areas compared with HAD samples. The characteristic mushroom flavor indicated by 8-carbon compounds such as 1-Octen-3-ol, 3-Octanone, etc.[29] were depicted in larger concentrations in CHCD samples compared with HAD and fresh samples. For example, 1-Octen-3-ol had a peak area of 39.1% in CHCD, which was 1.7 times its concentration in HAD (23.67%) and 3.6 times its concentration in fresh (10.73%). Da Costa and Eri[30] reported some other important volatiles, such as dimethyl disulfide, dimethyl trisulfide, trithiolanes, and terathianes which were also found in more concentrations in CHCD samples. Thus, the results substantiate that CHCD prevents the loss of significant volatile compounds which are responsible for the characteristic flavor/aroma of shiitake mushrooms.
A novel practical preparation of methyl methanethiosulfonate from dimethyl sulfoxide initiated by a catalytic amount of (COCl)2 or anhydrous HCl
Published in Journal of Sulfur Chemistry, 2021
Shuai Huang, Hao Wang, Yongguo Liu, Baoguo Sun, Hongyu Tian, Sen Liang
There are two known preparation methods of MMTS involving DMSO. One was reported by Laszlo and Mathy [30], who discovered it accidentally when preparing formaldehyde acetals from alcohols and chlorotrimethylsilane in the presence of DMSO. As pointed out by Maes et al., this method is unpractical in terms of atom economy, reaction mass efficiency, and reaction process mass intensity [1]. The other method was reported by Rätz and Sweeting in which MMTS was obtained as a byproduct without yield given [58]. Evidently, the synthesis of MMTS in this present work is distinct from those reported in the literature. Compared with the existing methods, our method is much more advantageous from the following aspects: (1) Clean conversion under benign experimental conditions within a short reaction time; (2) Low synthetic cost and high reproducibility. In practice, producing 1 equivalent of MMTS requires about 6 equivalents of DMSO and less than 0.6 equivalents of (COCl)2 or HCl. The reactions have been repeated many times with high reproducibility. The reagents are cheap and the solvent can be recycled. Among all the existing methods, it is worth noting that Maddaluno et al. reported that MMTS was obtained in 86% yield by the oxidation of dimethyl disulfide with hydrogen peroxide in AcOH [29]. Although it took 24 h to complete the reaction without large scale data, it looks quite practical. Compared with this method, our method has several advantages, such as short reaction time, catalytic amount of reagent, and recyclable solvent.
Review of the effects of wastewater biosolids stabilization processes on odor emissions
Published in Critical Reviews in Environmental Science and Technology, 2019
Ruth M. Fisher, Juan Pablo Alvarez-Gaitan, Richard M. Stuetz
The degradation of organic matter throughout wastewater treatment can produce a range of odorous products (Table 1), many of which have been detected in emissions from biosolids (Table S3). VSCs are typically attributed as the dominant odorants in sewers and WWTPs due to their predominance in emissions, low ODT and unpleasant odors typical of rotten eggs or cabbage (Devai & DeLaune, 1999; Sivret, Wang, Parcsi, & Stuetz, 2016). VSCs, of some form, were identified in many studies for each of the stabilization methods (Table S3). Most commonly reported were hydrogen sulfide (H2S), methyl mercaptan (MeSH), dimethyl sulfide (DMS), dimethyl disulfide (DMDS) and carbon disulfide (CS2). Organic VSCs (VOSCs) are typically produced from the degradation of sulfur containing proteins such as methionine or cysteine. H2S may be produced from the reduction of sulfate which commonly occurs in wastewater, and/or the degradation of proteins or other VSCs (Table 1).