Brhein's Weblog

Chemical reaction dynamics

brhein — Wed, 29 Apr 2009 16:48:14 +0000

Understanding the motions of the constituent atoms in reacting molecules lies at the heart of chemistry and is the central focus of chemical reaction dynamics. The most detailed questions one can ask are about the evolution of molecules prepared in a single quantum state to products in individual states, and both calculations and experiments are providing such detailed understanding of increasingly complex systems. A central goal of these studies is uncovering the essential details of chemical change by removing the averaging over the initial conditions that occurs in many cases. Such information provides an exquisite test of theory and helps paint pictures of complicated chemical transformations. The goal of this Special Feature is to provide a snapshot of a portion of the field of chemical reaction dynamics. Much of the work presented here emphasizes a close interplay of experiment and theory in ways that sharpen the conclusions of both and animate future studies. The articles do not completely cover the rich field of chemical reaction dynamics but rather provide a glimpse of some of the emerging insights. Reprinted by permission of the publisher.

Journal Name: Proceedings of the National Academy of Sciences of the United States of America
Source: Proceedings of the National Academy of Sciences of the United States of America v. 105 no. 35 (September 2 2008) p. 12647-8
Publication Year: 2008

Toxin town

brhein — Wed, 29 Apr 2009 16:45:46 +0000

Ten years after the Bhopal chemical plant disaster, the free-market policies of the Indian government could cause more tragedies. In 1984, the Union Carbide pesticide factory released over 40 tons of lethal methyl-isocyanate gas into the slums of Bhopal, killing, according to recent figures, over 6,600 people and injuring more than 70,000, who are still suffering. Since then, the catastrophe’s impoverished victims have been ill-served by the Indian government, which did not pursue the victims’ case aggressively in the Indian courts. The government chose instead to go easy on Union Carbide and maintain a favorable investment climate. Today, the lessons of Bhopal seem to have been ignored by the government. India’s neoliberal regime has encouraged transnationals to return en masse to the country. The free-marketeering government is destroying the country’s environmental, health, and safety protections to keep the investment flowing.

Personal Author: Karliner, Joshua
Journal Name: New Statesman & Society
Source: New Statesman & Society v. 7 (December 2 1994) p. 18-19
Publication Year: 1994

Methyl Isocyanate Exposure and Growth Patterns of Adolescents in Bhopal

brhein — Wed, 29 Apr 2009 16:44:54 +0000

The effects of exposure to fumes from a pesticide plant incident at Bhopal, India, on the physical growth pattern of adolescents were investigated. Over 200,000 people were exposed to methyl isocyanate and other gases following the incident at the Union Carbide Pesticide Plant on December 3, 1984. Anthropometric measurements were taken from exposed adolescents as well as in age and sex-matched unexposed individuals between May 10 and June 30, 2001. Selective growth retardation was identified in boys but not in girls who were either exposed to the plant’s gases as toddlers or born to exposed parents. This finding that exposed and unexposed girls were virtually identical in all measures indicates that the exposed and unexposed groups were well-matched and that the effects observed in boys is the result of exposure and not of other unobserved differences in the demographics.

Personal Author: Ranjan, Nishant; Sarangi, Satinath; Padmanabhan, V. T.
Journal Name: JAMA
Source: JAMA v. 290 no. 14 (October 8 2003) p. 1856-7
Publication Year: 2003

The practical chemistry of boom and bust

brhein — Wed, 29 Apr 2009 16:43:29 +0000

Researchers at the Explosions and Flame Laboratory of Britain’s Health and Safety Executive have saved the lives of miners, sailors, and other workers in dangerous occupations by studying why certain things explode or fail to explode. In the 1950s, a team led by Harold Titman and Steve Margerson found that light alloys such as magnesium, which were long believed to be nonsparking, can ignite an explosion when they strike rusty metal. Such alloys began to be banned in British mines after the findings were announced, but one expert says that the metals are still misused. More recently, explosives chemist Mike Kennedy and his colleagues averted potentially fatal mining accidents by discovering that “mining safety explosives,” which are weaker than ordinary ones, may fail to go off as planned if they are compressed by earlier explosions. As a result, manufacturers modified their explosives to make them less easily compressed.

Personal Author: Cherfas, Jeremy
Journal Name: Science
Source: Science v. 248 (April 6 1990) p. 35
Publication Year: 1990

The art of chemistry

brhein — Wed, 29 Apr 2009 16:41:58 +0000

Achieving the desired outcome of a chemical reaction in a controlled manner is at the heart of the challenge for synthetic organic and inorganic chemists. The creativity involved in combining elements into unprecedented molecules and materials distinguishes chemists from other scientists. A key goal for the synthetic organic chemist is the design of reagents to achieve chemical transformations at specific sites in a molecule without the need for protection and deprotection steps. Inorganic synthetic chemists attempting to mimic an enzymatic transformation also face the challenge of creating an environment that stabilizes the ligand composition at the metal ion, while offering labile sites for the catalysis. Therefore, the challenges that face synthetic chemists often require the ability to react a single part of a molecule to the exclusion of others.

Personal Author: Lippard, Stephen J.
Journal Name: Nature
Source: Nature v. 416 no. 6881 (April 11 2002) p. 587
Publication Year: 2002

Patching Physics and Chemistry Together

brhein — Wed, 29 Apr 2009 16:40:48 +0000

The “usual story” regarding molecular chemistry is that it is roughly an application of quantum mechanics. That is to say, quantum mechanics supplies everything necessary and sufficient, both ontologically and epistemologically, to reduce molecular chemistry to quantum mechanics. This is a reductive story, to be sure, but a key explanatory element of molecular chemistry, namely molecular structure, is absent from the quantum realm. On the other hand, typical characterizations of emergence, such as the unpredictability or inexplicability of molecular structure based on quantum mechanics, do not characterize the relationship between molecular chemistry and quantum mechanics well either. A different scheme for characterizing reduction and emergence is proposed that accommodates the relationship between quantum mechanics and molecular chemistry and some initial objections to the scheme are considered. Reprinted by permission of the publisher.

Personal Author: Bishop, Robert C.
Journal Name: Philosophy of Science
Source: Philosophy of Science v. 72 no. 5 (December 2005) p. 710-22
Publication Year: 2005

Revisiting the Bhopal Tragedy

brhein — Wed, 29 Apr 2009 16:39:20 +0000

Researchers are poised to conduct several studies that could shed light on the Bhopal tragedy and its health consequences. On the night of December 2-3, 1984, more than half a million people were exposed to a cloud of poisonous gases when water leaked into a storage tank filled with methyl isocyanate (MIC) at a pesticide factory in Bhopal, India. At least 3,000 people died as a result of breathing in the gases and at least another 5,000 survivors are still being treated for gas-related illnesses. Researchers from India and North America now plan to determine if there are anomalies in the lung surfactants of gas victims and if there are genetic mutations that MIC and other chemicals could have triggered in gas victims and their children. The scientists also intend to examine the health of young adults who were exposed in utero to the gas and to recreate the accident in order to determine what the victims were exposed to.

Journal Name: Science
Source: Science v. 306 (December 3 2004) p. 1670-1
Publication Year: 2004

Bibliography Revised

brhein — Wed, 29 Apr 2009 16:36:23 +0000

1.Crabb, Charlene. Revisiting the Bhopal Disaster. 2004

2.Broughton, Edward. The Bhopal Disaster and its aftermath. 2005

3.Willev, Ronaldo. The Accident in Bhopal: Observation 20 years later. 2006.

4.Kalelkar, Ashok. Investigation of Large-Magnitude Incidents: Bhopal As a Case Study. 1988.

5.Willev, Ronald. Bhopal Revisted. Chemical & Engineering: 2007.

Bibliography Draft

brhein — Wed, 29 Apr 2009 16:35:29 +0000

1. Crabb, Charlene. “Revisiting the Bhopal Disaster”

2.Broughton, Edward. “The Bhopal Disaster and Its Aftermath”

3. Willev, Ronald. “The Accident In Bhopal: Observation 20 Years Later.

4.Kalkelar, Ashok. “Investigation of Large-Magnitude Incidents: Bhopal As a Case Study

Reference Visit

brhein — Wed, 29 Apr 2009 16:09:41 +0000

Data Collected