Dow Chemical (Netherlands)

Abstract We summarize the patent literature related to the direct oxidation of propylene‐to‐propylene oxide (DOPO) over silver catalysts. Inventions claiming new compositions, preparation methods, and/or alternative process options are illustrated with data sampled from patent documents. Early claims focused on powders of silver (silver oxide) alloyed with and/or surface‐modified with one‐two promoterswhere silver was in large excess (>80 wt%). In the following decades, inventors refined their approach and pursued alternative bulk synthetic methods supplemented with impregnation to produce formulationscontaining lower amounts of silver in combination with various other transition metals, halides, alkalis and/or alkaline earth elements. Simultaneously, process development has facilitated increased PO selectivity via the co‐feeding of water and/or carbon dioxide at volume percent levels combined with smaller ppmV concentrations of organic chlorides and nitrogenoxides. At the end we briefly discuss how non‐catalytic oxidative routes to propylene oxide provide additional insights for new catalyst development. While these approaches hardly exceed 60 % PO selectivity, they may shed light on design criteria for catalysts capable of achieving that goal. Success in the field will require strong fundamental understanding of the activation of dioxygen on catalytic surfaces to define design requirements for silver catalystswith high selectivity to PO via direct oxidation.

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A bifunctional catalyst was developed utilizing a physical mixture of a CrZn-based mixed metal oxide and zeotype SAPO-34 for the direct conversion of syngas to short-chain olefins. A series of promoted CrZn-M (M = Fe, Ga, Al) mixed oxide catalysts were synthesized by coprecipitation and calcined at different temperatures. CrZn-Fe-SAPO-34 catalysts calcined at 400 °C selectively converted syngas to C2–C4 olefins, while maintaining high CO conversion and olefin stability over time. The high olefin yield is ascribed to the stabilization effect of iron on inversed spinel phase ZnCr2O4 and to reduction of the detrimental ZnO phase formed during syngas conditions. At a higher calcination temperature of 600 °C, the stabilization effect is less pronounced. Ga and Al-doped CrZn oxides enabled high and stable olefin selectivity of the hybrid catalysts CrZn-Ga-SAPO-34 and CrZn-Al-SAPO-34, regardless the applied calcination temperature. Spectroscopy analysis demonstrated that these promoters are able to scavenge free ZnO formed on the catalyst, thus stabilizing the inversed spinel. This work demonstrates that a rational design of mixed metal oxide components of the hybrid catalyst process is required to maximize olefin yield and catalyst stability. The selection of dopants capable of stabilizing an inversed spinel phase and scavenging detrimental ZnO is a critical step in successful catalyst design.

Unique among books on the topic, this new anthology brings together the voices of the executives, plant managers, investors, inventors, regulators, policymakers and advocates leading industry to sustainable water use. In their own words they tell how they redesign facilities to operate in water-short areas, change the rules to encourage responsible water use, and bridge the gap between companies and communities. They also report on the risks facing industry, and the tools they use to measure, treat, and reuse water more sustainably.The forty articles in this volume are organized into three sections. In "Perspectives," industrialists and the consultants who advise them are joined by academics, environmental and social organizations, and indigenous people whose communities are impacted by industry. In "Incentives and Barriers," authors explore what motivates industry to use water sustainably, and what barriers stand in their way. "Tools" reports on strategies to evaluate water use and prioritize improvements, and new technology that turns industrial wastewater into a resource.Although the subject is complicated, the authors provide useful guidance about real-world challenges in plain terms understandable to everyone. Their descriptions of the challenges they confront are intended to serve as the opening session of a "global town hall" among the many stakeholders who must work together to achieve sustainable industrial water use.ISBN: 9781789060669 (paperback)ISBN: 9781789060676 (eBook)

This chapter provides a survey of the different on-line environmental measurements that are commonly practiced in the oil and gas industry as well as a discussion on the emerging remote monitoring techniques. On-line analyzers are designed to do one specific analysis with minimal on-going maintenance. There are two general classes of sampling systems, extractive and non-extractive. Extractive sampling refers to a sample being taken from the process at regular intervals to be injected into the analyzer. Non-extractive sampling can only be used with techniques that do not alter the sample. Water analysis in the oil and gas industry involves samples from reservoir formations and production that must be monitored to maintain the integrity of reservoirs and wells. There are a variety of techniques that are used for fenceline monitoring. Fenceline monitoring is intended to identify and quantify fugitive emissions.

<p>ABSTRACT<br>\nThis paper derives an occupational exposure limit for benzene using quality assessed data. Seventy-seven genotoxicity and 36 haematotoxicity studies in workers were scored for study quality with an adapted tool based on that of Vlaanderen et al 2008 (Environ Health. Perspect. 116 1700-5). These endpoints were selected as they are the most sensitive and relevant to the proposed mode of action and protecting against these will protect against benzene carcinogenicity.<br>\nLowest and No- Adverse Effect Concentrations (LOAECs and NOAECs) were derived from the highest quality studies (i.e. those ranked in the top tertile or top half) and further assessed as being “more certain” or “less certain”. Several sensitivity analyses were conducted to assess whether alternative “high quality” constructs affected conclusions.<br>\nThe lowest haematotoxicity LOAECs showed effects near 2 ppm (8h TWA), and no effects at 0.59 ppm. For genotoxicity, studies also showed effects near 2 ppm and showed no effects at about 0.69 ppm. Several sensitivity analyses supported these observations. These data define a benzene LOAEC of 2 ppm (8h TWA) and a NOAEC of 0.5 ppm (8h TWA).<br>\nAllowing for possible subclinical effects in bone marrow not apparent in studies of peripheral blood endpoints, an OEL of 0.25ppm (8h TWA) is proposed.</p>