Types of Chemists

Several different types of chemists will benefit from reading this work ... 

A police detective has confiscated as evidence some chicken soup that he suspects might contain poison. Which type of chemist would most likely assist him in determining the contents of the soup ... 

This is not to say that chemists in the chemical industry had or have no interest in designing safer commercial chemicals, or do not strive to make useful chemicals that are safe - quite the contrary, as this chapter and others in this book illustrate. However, since there are no pre-market test requirements for characterizing the safety of new commercial chemicals, there is a considerably small driving force for chemical manufacturers to devote resources to designing chemicals that are commercially efficacious and safe. More bluntly, because it is relatively inexpensive under the TSCA to get a new commercial chemical on the market, enactment of the TSCA did not lead to the evolution of a new type of chemist analogous to the medicinal chemist in the case of drugs. Thus, despite the enactment of the TSCA over 3 5 years ago, the status quo in the chemical industry has persisted. 

Hphe term anomeric effect was introduced by Lemieux in 1958 as a result of a detailed study of the anomerization of acetylated pento-and hexo-pyranoses. The effect is well known to carbohydrate chemists, and refers to the tendency of an electronegative substituent at C-l of a pyranoid ring to assume the axial rather than equatorial orientation, in contrast to predictions based solely on steric grounds. However, the phenomenon is not restricted to carbohydrate systems, but is displayed in many types of heterocyclic compounds. Thus, the investigation of the anomeric effect has been of considerable interest to a variety of chemists, namely, theoreticians, structural chemists, physical organic chemists, and synthetic chemists. Chemists from all of these areas participated in the Symposium on The Origin and Consequences of the Anomeric Effect. This symposium was the first symposium devoted exclusively to a discussion of the anomeric effect, and it provided a mechanism for interactions between the diverse types of chemists. The chapters in this volume are not merely the texts as presented at the symposium, but they also incorporate some new interpretations by the authors resulting from these interactions. 

Types of Chemists would be a very different place. 

This book is, of course, a must for organometallic chemists and supramolecular chemists alike, but it is also of great value for all other types of chemist who at one time or another encounter these two domains. 

Which direction will future research on coordination compounds take Many complex enqmiic reactions depend on the unique qualities of transition metal atoms at their reaction centers. Complex chemistry holds their k, and th will become its next growing edge. Their solution will demand close cooperation among all types of chemists. 

Unfortunately, decisions on the ultimate hazards of a product are not determined by either toxicologists or scientists, but by attorneys and jurors in a court of law where no one is likely to have a clear understanding of words such as physical chemist. What does a physical chemist really do in an industry I ask the question because I am one and I have practiced the science for almost half a century. It is also unfortunate that most industrial management does not have a foggy notion of what a physical chemist does. Most other types of chemists are not too comfortable with their definitions. 

The author of the report, who promoted organisation and collaboration, was Albert Werner Cronquist (1846-1910), who deserves a few words of introduction. He was a new type of chemist, working with industry, by taking on the role of a consultant chemist, making a living from his chemical education, not at a university nor in industry, but as a private entrepreneur. The sheer bulk of his activities is... 

A letter from Victor Meyer of the polytechnic in Zurich provides a clue as to the type of chemist Caro was looking for ... 

We have tried to present the electronic theory of acids and bases and its ramifications in an elementary manner. The theory is of interest to all types of chemists, and the book has been written with that in mind. Three chapters (10, 11, and 12) contain details on catalysis which are of most interest to organic chemists, but if necessary they can be skipped without losing continuity Chapter 9 gives the essence of their contents. 

The ROSDAL syntax is characterized by a simple coding of a chemical structure using alphanumeric symbols which can easily be learned by a chemist [14]. In the linear structure representation, each atom of the structure is arbitrarily assigned a unique number, except for the hydrogen atoms. Carbon atoms are shown in the notation only by digits. The other types of atoms carry, in addition, their atomic symbol. In order to describe the bonds between atoms, bond symbols are inserted between the atom numbers. Branches are marked and separated from the other parts of the code by commas [15, 16] (Figure 2-9). The ROSDAL linear notation is rmambiguous but not unique. 

Thus, computers will continue to penetrate every aspect of chemistry and we have to prepare the next generation of chemists for this process. In fact, we will see that the various types of computer applications in chemistry will increasingly be used in concert to solve chemical problems. Therefore, a unified view of the entire field is needed the various approaches to using computers in chemistry have to be ordered into a common framework, into a disdpline of its own Chemoinfor-matics. 

Solvents exert their influence on organic reactions through a complicated mixture of all possible types of noncovalent interactions. Chemists have tried to unravel this entanglement and, ideally, want to assess the relative importance of all interactions separately. In a typical approach, a property of a reaction (e.g. its rate or selectivity) is measured in a laige number of different solvents. All these solvents have unique characteristics, quantified by their physical properties (i.e. refractive index, dielectric constant) or empirical parameters (e.g. ET(30)-value, AN). Linear correlations between a reaction property and one or more of these solvent properties (Linear Free Energy Relationships - LFER) reveal which noncovalent interactions are of major importance. The major drawback of this approach lies in the fact that the solvent parameters are often not independent. Alternatively, theoretical models and computer simulations can provide valuable information. Both methods have been applied successfully in studies of the solvent effects on Diels-Alder reactions. 

The modem organic chemist has a variety both of reagents and reactions far beyond those we have looked at here. If you study organic chemistry to a more advanced level you should meet many of them but you will find that the principles of their design and use are the same as those you have learnt in this programme. We have now finished the basic types of disconnection and must look at the strategy of synthesis. 

Most chemists want to avoid the paper-and-pencil type of work that theoretical chemistry in its truest form entails. However, keep in mind that it is precisely for this kind of painstaking and exacting research that many Nobel prizes have been awarded. This book will focus almost exclusively on the knowledge needed to effectively use existing computer software for molecular modeling. 

These types of businesses are the prime choice a chemist will use to get that specialty chemical or piece of glassware. There are thousands of such places around the nation, Canada and Mexico. 

There are some alternatives to this HCI generator type of crystallization. There are, of course, canisters of HCI gas that can be purchased. Also, one can crystallize with very concentrated (fuming) HCI by pouring the stuff directly into the ether/freebase [26]. Regular 35% HCI can do this too, but the water content may dissolve the MDA.HCl or make the crystals sticky which means that the chemist will have to dry the solution by removing the water. 

The way the chemist knows that she has methylamine and not ammonium chloride is that she compares the look of the two types of crystals. Ammonium chloride crystals that come from this reaction are white, tiny and fuzzy. The methylamine hydrochloride crystals are longer, more crystalline in nature and are a lot more sparkly. The chemist leaves the methylamine crystals in the Buchner funnel of the vacuum filtration apparatus and returns the filtrate to the distillation set up so it can be reduced one last time to afford a second crop. The combined methylamine hydrochloride filter cake is washed with a little chloroform, scraped into a beaker of hot ethanol and chilled. The methylamine hydrochloride that recrystallizes in the cold ethanol is vacuum filtered to afford clean, happy product (yield=50%). 

Best Synthetic Methods is now 10 years old, is a family of 16 volumes and has been well received by the majority of chemists as a valuable aid in their synthetic endeavours, be they academic or commercial. The focus of the series so far has been on special methods, reagents or techniques. This volume is the first of a new sub-series with a focus on heterocycles and their synthesis. It is amazing the extent to which each heterocyclic type has its own specialized synthetic methodology. Whether the chemist is endeavouring to make a heterocycle by ring synthesis or wishes to introduce specific substituents, it is the intention that this new development will serve their needs in a practical, authoritative, fully illustrative and compact manner. Richard Sundberg is an authority on indole chemistry and it is a pleasure to have such a noted heterocyclist to initiate this venture. 

Analytical chemists use a variety of glassware to measure volume, several examples of which are shown in Figure 2.4. The type of glassware used depends on how exact the volume needs to be. Beakers, dropping pipets, and graduated cylinders are used to measure volumes approximately, typically with errors of several percent. 

The flavor chemist is responsible for the basic knowledge of sensory and appHcation properties of each of this large number of raw materials the large number of possible combinations of these items to produce specifically flavored finished compounds is readily apparent. It is not uncommon to develop a flavor that combines essential oils, plant extractive, fmit juices, and synthetics. The choice of materials depends on type of product, conditions of manufacture, labeling, and intended use. 

Eorensic science laboratories may have different missions and therefore conduct different types of testing on samples (21,22). Eor example, the United States Department of Justice, Dmg Enforcement Administration (DEA) forensic laboratories assist authorities ia criminal intelligence-gathering efforts. As such, DEA chemists routinely analyze both the iUicit dmg and excipient, the material used ia the cutting or diluting of the pure dmg, ia a given specimen. The excipient may provide information as to where the sample was produced. 

---