Showing papers in "Chemical & Engineering News in 2002"
TL;DR: Olefin metathesis is a popular and useful reaction for many transition-metal compounds, including various metal carbenes, resulting in several outcomes, such as straight swapping of groups between two acyclic olefins (cross-metathesis), closure of large rings (ring-closing metatheses), formation of dienes from cyclic and acyCLic OE, and polymerization of cyclic oE ensembles as mentioned in this paper.
Abstract: OLEFIN METATHESIS IS A POPULAR AND USEFUL REACtion. In the presence of certain transition-metal compounds, including various metal carbenes, olefins exchange the groups around the double bonds, resulting in several outcomes: straight swapping of groups between two acyclic olefins (cross-metathesis), closure of large rings (ring-closing metathesis), formation of dienes from cyclic and acyclic olefins (ring-opening metathesis), polymerization of cyclic olefins (ring-opening metathesis polymerization), and polymerization of acyclic dienes (acyclic diene metathesis polymerization). The power of olefin metathesis is that it transforms the carbon-carbon double bond, a functional group that is unreactive toward many reagents that react with many other functional groups. With certain catalysts, new carbon-carbon double bonds are formed at or near room temperature even in aqueous media from starting materials that bear a variety of functional groups. The catalysts are available commercially, making the reaction ac...
69 citations
59 citations
TL;DR: Analytical chemists and engineers are developing ways to monitor glucose that are minimally invasive or even noninvasive, described in a daylong symposium sponsored by the Division of Analytical Chemistry.
Abstract: DIABETES IS CHARACTERIZED BY high levels of blood glucose resulting from the inability to produce or effectively use insulin. A 10-year Diabetes Control & Complications Trial (DCCT) found that tight control of glucose levels can greatly reduce the long-term complications associated with the disease, such as eye, kidney, and nerve disorders. DCCT was conducted by the National Institute of Diabetes & Digestive & Kidney Diseases. The best way to maintain normal glucose levels is with frequent monitoring, which requires patients to prick their fingers to take small blood samples several times a day. Then they can take steps to adjust their insulin levels, if necessary, in a timely way. But patients would like alternatives to sticking themselves. In response, analytical chemists and engineers are developing ways to monitor glucose that are minimally invasive or even noninvasive. Some of these methods were described in a daylong symposium sponsored by the Division of Analytical Chemistry. ...
37 citations
TL;DR: U.S. Pharmacopeia and NSF International are prepared to review labels on dietary supplements, verify in-gredients, and ensure that suppliers use Good Manufacturing Practices (GMP) based on proposed FDA rules.
Abstract: CONSUMERS DON'T ALWAYS KNOW what they are getting in a bottle of vitamins, minerals, herbs, or other dietary supplements. Product labels don't always accurately reflect ingredients, which may sometimes be contaminated with heavy metals or other impurities. And consumers often buy these products without any clear idea of what they are supposed to do. Even purchasing agents at supplement manufacturers are not always sure of the quality and potency of the ingredients they buy They may test suppliers' ingredients on their own or through contract labs. However, test methods employed don't necessarily test for heavy metals, pesticides, and other contaminants. But help is on the way. In the absence of stringent government regulation of the industry—by law, supplements are regulated as foods, not drugs—U.S. Pharmacopeia and NSF International are prepared to review labels on o dietary supplements, verify in- |gredients, and ensure that suppliers use Good Manufacturing Practices (GMP) based on |proposed FDA rules. ...
33 citations
TL;DR: The number of Chemical Society members who wanted to work hit a 30-plus-year high of 33% in March of 2013, according to the American Chemical Society (ACS) as mentioned in this paper.
Abstract: THE EMPLOYMENT MARKET FOR CHEMISTS HAS DETEriorated sharply over the past year. Unemployment among American Chemical Society members who wanted to work hit a 30-plus-year high of 33% in March of th...
30 citations
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TL;DR: The International Combustion Engin Engine almost started out green as mentioned in this paper, when Rudolph Diesel unveiled his invention at the World Exhibition in Paris, his fuel of choice was peanut oil.
Abstract: THE INTERNAL COMBUSTION ENgine almost started out green. Back in 1900, when Rudolph Diesel unveiled his invention at the World Exhibition in Paris, his fuel of choice was peanut oil. The diesel eng...
29 citations
TL;DR: In spite of seven years of intrusive United Nations inspections and decimation of Iraq's WMD, Iraq was able to sequester sizable stocks of chemical and biological weapons, some of which were later used by Iran.
Abstract: DESPITE SEVEN YEARS OF INtrusive United Nations inspections and decimation of Iraq's weapons of mass destruction, Iraq was able to sequester sizable stocks of chemical and biological weapons, some ...
28 citations
TL;DR: In the 18th century, as chemists isolated many elements for the first time and synthesized many new colored compounds from them, they also gave rise to a burgeoning artists' palette.
Abstract: COLOR, THEY SAY, DOESN'T EXIST. It is only an effect produced in the brain after some cells in the eye have undergone a photochemical reaction; and sometimes color is "perceived" even without that stimulus. So it is fascinating that we humans spend time and money, in large amounts, on materials solely for their color. Chemists, too, have devoted considerable research, both fundamental and applied, to compounds solely on account of their color. To realize this, one need only recall the experiments on why chlorophyll is green or the drive of industrial chemists to find brightly colored dyes. In the 18th century, as chemists isolated many elements for the first time and synthesized many new colored compounds from them, they also gave rise to a burgeoning artists' palette. In "Bright Earth: Art and the Invention of Color," British science writer Philip Ball takes on the challenge of explaining color and the allure ...
27 citations
TL;DR: In fact, the two disciplines have merged to give birth to a new field of bio-organometallic chemistry as mentioned in this paper, which focuses on compounds of biological interest where the chemistry of the metal-carbon bonds is a central feature.
Abstract: ONCE UPON A TIME, ORGANOMETALlic chemistry and biology were viewed as disparate, mutually incompatible fields of research. Most organometallic compounds were thought to be inherently sensitive to water and oxygen—substances that are essential for biology. But as researchers delved deeper into organometallic chemistry, they began to realize that much of this field is quite compatible with biology. In fact, in the past decade or so, the two disciplines have merged to give birth to a new field—bioorganometallic chemistry. Research in this nascent field focuses on compounds of biological interest where the chemistry of the metal-carbon bonds is a central feature, says Gerard Jaouen, a chemistry professor at Ecole Nationale Superieure de Chimie de Paris (ENSCP). Jaouen, one of the field's most visible boosters, believes that organometallic compounds may offer innovative solutions to some difficult biological problems, such as breast cancer—his main research interest. Chemist Richard H. Fish of Lawrence Berkele...
27 citations
TL;DR: In this article, two research teams have independently reported the development of iridium catalyst systems that allow for an abbreviated version of the popular Suzuki coupling reaction, and the main feature of the new...
Abstract: TWO RESEARCH TEAMS HAVE INDEPENDENTLY reported the development of iridium catalyst systems that allow for an abbreviated version of the popular Suzuki coupling reaction. The main feature of the new...
TL;DR: In this article, the company is making samples of aqueous glutaric acid available to customers, and it hopes to sell commercial quantities by the end of the year, with the aim of opening up latent applications.
Abstract: DUPONT NYLON INTERMEDIATES & Specialties—which markets polymer raw materials and specialty chemicals based on the nylon chain—is starting a glutaric acid business. DuPont hopes that putting millions of pounds of a currently scarce product at customers' disposal will open up latent applications. Glutaric acid, a five-carbon dicarboxylic acid, is a by-product of adipic acid production. DuPont says about 2% of the output of an adipic acid plant is glutaric. However, this chemical doesn't usually reach the market because it is converted into dibasic esters, which DuPont and other adipic acid makers such as Solutia sell as environmentally friendly solvents. DuPont wants to extract glutaric acid and sell it directly to customers in niche applications. This spring, the company is making samples of aqueous glutaric acid available to customers, and it hopes to sell commercial quantities by the end of the year. "Today, glutaric is not readily available anywhere," says Keith ...
Journal Article•
TL;DR: Welch as mentioned in this paper argues that the chiral technology revolution was founded on the ability to measure enantiomeric purity, and that without reliable measurement techniques, no one could have done very much.
Abstract: \"The chiral technology revolution was founded on the ability to measure enantiomeric purity,\" says Christopher J. Welch, a process research fellow at Merck Research Laboratories, Rahway, N.J. Research in chiral technology exploded only after chiral columns for liquid chromatography became commercially available in 1981, he notes. The columns offered a way to measure enantiomeric excess (ee) that is much better than polarimetry. \"Without the reliable measurement techniques, no one could have done very much,\" he notes.
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TL;DR: In this paper, the ingredients list of California seedless raisins, sulfur dioxide added as a preservative, is shown to keep the golden variety golden until recently, when I looked at the ingredient list.
Abstract: JUST THIS YEAR, I DISCOVERED golden raisins. I like their light flavor in my morning oatmealnot too sweet, and milder than their darker cousins. I didn't wonder what keeps the golden variety golden until recently, when I looked at the ingredients list: California seedless raisins, sulfur dioxide added as a preservative. Chemical preservatives like sulfur dioxide help keep food fresh. Of the 32 ingredients in my favorite type of granola bar (oatmeal raisin), one is labeled as a preservative, although a few other ingredients also inhibit decay. Some grocery items have no preservatives at allin particular those that are sufficiently preserved by freezing, drying, smoking, pickling, canning, or some other means. Chemical preservatives can't replace more stringent preservation methods, such as commercial sterilization, which destroys most enzymatic and bacterial activity. But chemicals can be used effectively to slow spoiling and keep microorganisms at bay. Preservatives can be categorized into three general...
TL;DR: Chan has taken her well-rounded interdisciplinary approach to several places in the U.S. and now to Louisiana where she is an assistant professor of chemistry at Louisiana State University (LSU) as mentioned in this paper.
Abstract: JULIA Y. CHAN CREDITS HER DEcision to become a chemist to the excellent undergraduate teaching at Baylor University, Waco, Texas. The fact that she chose the school based on its music department is a testament to her pursuit of a balanced life. "You need to strike a balance in science; you need to present and relate to people—that comes from my liberal arts education, and I think it's very important." Chan has taken her well-rounded interdisciplinary approach to several places in the U.S. and now to Louisiana where she is an assistant professor of chemistry at Louisiana State University (LSU). As an inorganic materials chemist, she looks for new superconductors by making new materials, characterizing them, and measuring their properties. Chan points out that her materials can be used for data storage and sensors—or any use that involves detecting small magnetic fields. Born in Malaysia, the 30-year-old chemist moved to the U.S. when she ...
TL;DR: In this paper, the authors presented a treatment for glass surfaces that killed a range of bacteria on contac... and drinking glasses that sanitize themselves using bandages that could kill bacteria.
Abstract: IMAGINE BANDAGES THAT COULD KILL bacteria or drinking glasses that sanitize themselves. Last year, a research group reported a treatment for glass surfaces that killed a range of bacteria on contac...
TL;DR: Green chemistry has been a hot topic in the last few years as mentioned in this paper, with a number of national and international conferences dedicated to green chemistry, and the topic popped up on the technical programs at American Chemical Society and other meetings.
Abstract: THIS HAS BEEN A STELLAR YEAR for green chemistry A number of national and international conferences were dedicated to green chemistry, and the topic popped up on the technical programs at American Chemical Society and other meetings. Several journals, including Science and Accounts of Chemical Research , published special sections or issues focusing on green chemistry, while others now flag green chemistry papers. The Royal Society of Chemistry's journal Green Chemistry is in its fourth year of publication, and the U.S.'s Presidential Green Chemistry Challenge Awards program celebrated its seventh anniversary. A few universities worldwide have added degree programs in green chemistry ACS's Green Chemistry Institute (GCI) and others have held numerous education workshops. Several universities also have established research centers dedicated to implementing green chemical technologies. And in addition to GCI in the U.S., national centers for green chemistry have been set up in the U.K., Japan, Italy, and Au...
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TL;DR: In the printing industry, water-based inks or those containing other environmentally friendly solvents have regained favor more than five centuries later, largely around volatile organic compounds (VOCs) and heavy metals in pigments as discussed by the authors.
Abstract: ALTHOUGH JOHANNES GUTENBERG IS KNOWN FOR creating movable metal type in 1456, his contribution to ink is less often acknowledged. Inks combine a colorant, namely a pigment or dye; a carrying vehicle, usually petroleum or vegetable oils, solvents, or water; resin binders; and additives such as wetting agents, waxes, and driers. When Gutenberg found that water-based inks were too fluid to print cleanly, his use of linseed oil as the vehicle set the course of printing. More than five centuries later, water-based inks or those containing other environmentally friendly solvents have regained favor. Environmental concerns, largely around volatile organic compounds (VOCs) and heavy metals in pigments, have compelled new chemistries and changes in formulations. Now, new technologies in both ink production and printing processes are presenting further challenges and added market opportunities. Pigments make up about 10% by weight of printing ink shipments, but they account for a more significant share of ...
Journal Article•
TL;DR: A parallel version of the Celada–Seiden–Bouchut–Boyaval synthesis, using a simple and scalable approach, has been shown to improve the quality and efficiency of the synthesis of cadmium chloride.
Abstract: CARBOHYDRATES ARE NOTORIously hard to synthesize, but recently several research groups have made major advances in simplifying and accelerating the process. One of those is the team of assistant pr...