نتایج جستجو برای: mercury free catalyst

تعداد نتایج: 593654  

This article describe the applicability of 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2].2Cl) as a green, versatile and Brönsted acidic ionic catalyst in the promotion of the synthesis of phthalazine derivatives via one-pot three component reaction between aromatic aldehydes, 1,3-diketone derivatives and phthalhydrazide under solvent-free reaction cond...

Oxalic acid dihydrate as a green, mild and efficient catalyst for the one-pot three-component Biginelli synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives from the reaction between β-keto esters (methyl or ethyl acetoacetate), aromatic aldehyde (benzaldehye derivatives) and urea or thiourea under thermal and solvent-free conditions with excellent yields and short reaction time is st...

2017
Romilda Z. Boerleider

Mercury (Hg) is a naturally occurring element that has metallic, inorganic and organic forms, each with their own implications for human health. Exposure to mercury primarily occurs by inhalation of metallic mercury vapors and by dietary intake of organic mercury. Early health effects are often not well detected. Therefore, determination of the internal dose is a valuable approach in primary pr...

Journal: :Environmental Health Perspectives 2002
Perri Zeitz Maureen F Orr Wendy E Kaye

We analyzed data from states that participated in the Hazardous Substances Emergency Events Surveillance (HSEES) system maintained by the Agency for Toxic Substances and Disease Registry to describe the public health consequences of mercury releases. From 1993 through 1998, HSEES captured 406 events in which mercury was the only substance released. Schools and universities, private residences, ...

2016
Ignacio G. Gonzalez-Martinez Thomas Gemming Rafael Mendes Alicja Bachmatiuk Viktor Bezugly Jens Kunstmann Jürgen Eckert Gianaurelio Cuniberti Mark H. Rümmeli

The catalyst-assisted nucleation and growth mechanisms for many kinds of nanowires and nanotubes are pretty well understood. At times, though, 1D nanostructures form without a catalyst and the argued growth modes have inconsistencies. One such example is the catalyst-free growth of aluminium borate nanowires. Here we develop an in-situ catalyst-free room temperature growth route for aluminium n...

Oxalic acid dihydrate as a green, mild and efficient catalyst for the one-pot three-component Biginelli synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives from the reaction between β-keto esters (methyl or ethyl acetoacetate), aromatic aldehyde (benzaldehye derivatives) and urea or thiourea under thermal and solvent-free conditions with excellent yields and short reaction time is st...

Journal: :iranian journal of medical physics 0
zeynab sanjabi m.sc. of radiation medicine dept., shahid beheshti university, tehran, iran. alireza kamali asl assistant professor, nuclear engineering dept., shahid beheshti university, tehran, iran mohammad hassan zahmatkesh associate professor, shahid beheshti university, evin, tehran, iran saeid bagheri m.sc. in medical physics, shahid beheshti university, tehran, iran

introduction: different dosimetric modalities (e.g., ionization chambers, semiconductors, tlds, radiographic films) often have some problems determining isodose curves and percentage depth doses in high dose gradient regions. research has been ongoing to develop portable high resolution dosimetry devices with accurate absolute dosimetry capabilities and easy data analysis. the ‘presage’ dosimet...

2017
Giuseppe Genchi Maria Stefania Sinicropi Alessia Carocci Graziantonio Lauria Alessia Catalano

Environmental contamination has exposed humans to various metal agents, including mercury. It has been determined that mercury is not only harmful to the health of vulnerable populations such as pregnant women and children, but is also toxic to ordinary adults in various ways. For many years, mercury was used in a wide variety of human activities. Nowadays, the exposure to this metal from both ...

2006
P. C. Swartzendruber D. A. Jaffe E. M. Prestbo P. Weiss-Penzias N. E. Selin R. Park D. J. Jacob S. Strode L. Jaeglé

[1] We measured gaseous elemental mercury (GEM), particulate mercury (PHg), and reactive gaseous mercury (RGM), along with CO, ozone, and aerosol scatter at the Mount Bachelor Observatory (2.7 km above sea level), Oregon, from May to August 2005. The mean mercury concentrations (at standard conditions) were 1.54 ng/m (GEM), 5.2 pg/m (PHg), and 43 pg/m (RGM). RGM enhancements, up to 600 pg/m, oc...

Ammonium monovanadate (NH4VO3) has been devoted as an efficient, commercially available, eco-friendly and reusable catalyst for the synthesis of bis(indolyl)methanes (BIMs), oxindole derivatives and also Michael adducts of indoles at 50 °C under solvent-free conditions. The reusability of this solid acid catalyst in addition with its selectivity has also been examined.

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