Industrial chemistry

The manufacture, sale, and distribution of chemical products is one of the cornerstones of a developed country. Chemists play an important role in the manufacture, inspection, and safe handling of chemical products, as well as in product development and general management. The manufacture of basic chemicals such as oxygen, chlorine, ammonia, and sulfuric acid provides the raw materials for industries producing textiles, agricultural products, metals, paints, and pulp and paper. Specialty chemicals are produced in smaller amounts for industries involved with such products as pharmaceuticals, foodstuffs, packaging, detergents, flavours, and fragrances. To a large extent, the chemical industry takes the products and reactions common to “bench-top” chemical processes and scales them up to industrial quantities.

The monitoring and control of bulk chemical processes, especially with regard to heat transfer, pose problems usually tackled by chemists and chemical engineers. The disposal of by-products also is a major problem for bulk chemical producers. These and other challenges of industrial chemistry set it apart from the more purely intellectual disciplines of chemistry discussed above. Yet, within the chemical industry, there is a considerable amount of fundamental research undertaken within traditional specialties. Most large chemical companies have research-and-development capability. Pharmaceutical firms, for example, operate large research laboratories in which chemists test molecules for pharmacological activity. The new products and processes that are discovered in such laboratories are often patented and become a source of profit for the company funding the research. A great deal of the research conducted in the chemical industry can be termed applied research because its goals are closely tied to the products and processes of the company concerned. New technologies often require much chemical expertise. The fabrication of, say, electronic microcircuits involves close to 100 separate chemical steps from start to finish. Thus, the chemical industry evolves with the technological advances of the modern world and at the same time often contributes to the rate of progress.

 Polymer chemistry

The simple substance ethylene is a gas composed of molecules with the formula CH2CH2. Under certain conditions, many ethylene molecules will join together to form a long chain called polyethylene, with the formula (CH2CH2)n, where n is a variable but large number. Polyethylene is a tough, durable solid material quite different from ethylene. It is an example of a polymer, which is a large molecule made up of many smaller molecules (monomers), usually joined together in a linear fashion. Many naturally occurring substances, including cellulose, starch, cotton, wool, rubber, leather, proteins, and DNA, are polymers. Polyethylene, nylon, and acrylics are examples of synthetic polymers. The study of such materials lies within the domain of polymer chemistry, a specialty that has flourished in the 20th century. The investigation of natural polymers overlaps considerably with biochemistry, but the synthesis of new polymers, the investigation of polymerization processes, and the characterization of the structure and properties of polymeric materials all pose unique problems for polymer chemists.

Polymer chemists have designed and synthesized polymers that vary in hardness, flexibility, softening temperature, solubility in water, and biodegradability. They have produced polymeric materials that are as strong as steel yet lighter and more resistant to corrosion. Oil, natural gas, and water pipelines are now routinely constructed of plastic pipe. In recent years, automakers have increased their use of plastic components to build lighter vehicles that consume less fuel. Other industries such as those involved in the manufacture of textiles, rubber, paper, and packaging materials are built upon polymer chemistry.

Besides producing new kinds of polymeric materials, researchers are concerned with developing special catalysts that are required by the large-scale industrial synthesis of commercial polymers. Without such catalysts, the polymerization process would be very slow in certain cases.

Inorganic chemistry

 Inorganic chemistry

 Inorganic chemistry is commonly thought of as those areas within chemistry that do not deal with carbon. However, carbon is very important in many inorganic compounds, and there is a whole area of study known as organometallic chemistry that is truly a hybrid of the traditional disciplines of organic and inorganic chemistry. Some areas of inorganic chemistry that are especially important are catalysis, materials chemistry, and bioinorganic chemistry. Catalysts are chemical entities that increase the rate of a reaction without being consumed, and are typically based upon transition metals (usually) organometallic complexes of transition metals).This is an extremely important area to industry, and many of the chemists who would be identified as inorganic or organometallic chemists work in this area. Materials Chemistry is an area concerned with the design and synthesis of materials that allow the advance of technologies in nearly every area of society. Often, inorganic chemists working in this area are concerned with the synthesis and characterization of solid state compounds or inorganic polymers such as silicones. Bioinorganic chemists study the function of metal-containing compounds within living organisms. Students who concentrate in inorganic chemistry often go on to work in industry in polymer or materials science, do research or teach in inorganic chemistry, or pursue other related job opportunities.

Organic chemistry 

Organic chemistry is a sub-field of chemistry that involves studying the molecules of life. It is mainly concerned with looking at the structure and behavior of these molecules, which are composed of only a few different types of atoms: carbon, hydrogen, oxygen, nitrogen, and a few miscellaneous others. These are the atoms used to construct the molecules that all plants and animals require for their survival. Traditional organic chemists are concerned with synthesizing new molecules and with developing new reactions that might make these syntheses more efficient. The kinds of molecules organic chemists synthesize include useful things like drugs, flavorings, preservatives, fragrances, plastics (polymers), and agricultural chemicals (fertilizers and pesticides), and sometimes include unusual molecules found in nature or ones that might simply provide a challenge to make. Also, understanding something about organic chemistry is essential for learning about biochemistry and molecular biology because bio-molecules such as proteins, sugars, fats, and nucleic acids (DNA and RNA) are all organic molecules, albeit very large ones. Students who concentrate in organic chemistry typically go on to work in pharmaceutical, food or polymer companies, do research or teach in organic chemistry, pursue medical careers, or may pursue other related job opportunities.

Different types of Chemistry

 

Different types of Chemistry

Fundamentally, chemistry is the study of matter and change. The way that chemists study matter and change and the types of systems that are studied varies dramatically. Traditionally, chemistry has been broken into five main subdisciplines: Organic, Analytical, Physical, Inorganic, and Biochemistry. Over the last several years, additional concentrations have begun to emerge, including Nuclear chemistry, Polymer chemistry, Biophysical chemistry, Bioinorganic chemistry, Environmental chemistry, etceteras. All of these areas of chemistry are addressed in our classes here at UWL to some extent, and by the research interests of our faculty in the Chemistry Department. The following descriptions of the five major subdisciplines were written by several of our faculty members in their field of expertise. All of our faculty members would be happy to elaborate, and/or discuss other aspects of chemistry that are not described below! UW-La Crosse's accredited Chemistry and Biochemistry programs blend technical, hands-on research experience with practical skill development.

Organic chemistry is a sub-field of chemistry that involves studying the molecules of life. It is mainly concerned with looking at the structure and behavior of these molecules, which are composed of only a few different types of atoms: carbon, hydrogen, oxygen, nitrogen, and a few miscellaneous others. These are the atoms used to construct the molecules that all plants and animals require for their survival. Traditional organic chemists are concerned with synthesizing new molecules and with developing new reactions that might make these syntheses more efficient. The kinds of molecules organic chemists synthesize include useful things like drugs, flavorings, preservatives, fragrances, plastics (polymers), and agricultural chemicals (fertilizers and pesticides), and sometimes include unusual molecules found in nature or ones that might simply provide a challenge to make. Also, understanding something about organic chemistry is essential for learning about biochemistry and molecular biology because bio-molecules such as proteins, sugars, fats, and nucleic acids (DNA and RNA) are all organic molecules, albeit very large ones. Students who concentrate in organic chemistry typically go on to work in pharmaceutical, food or polymer companies, do research or teach in organic chemistry, pursue medical careers, or may pursue other related job opportunities.

Analytical chemistry is the science of identification and quantification of materials in a mixture. Analytical chemists may invent procedures for analysis, or they may use or modify existing ones. They also supervise, perform, and interpret the analysis. Students concentrating in analytical chemistry often go on to work in forensics laboratories, environmental or pharmaceutical companies, work in, manage and/or design quality assurance procedures, pursue research, or teach in colleges and universities.

Physical chemistry is the study of the fundamental physical principles that govern the way that atoms, molecules, and other chemical systems behave. Physical chemists study a wide array of topics such as the rates of reactions (kinetics), the way that light and matter interact (spectroscopy), how electrons are arranged in atoms and molecules (quantum mechanics), and the stabilities and reactivities of different compounds and processes (thermodynamics). In all of these cases, physical chemists try to understand what is happening on an atomic level, and why. Students who concentrate in physical chemistry may go onto pursue careers in industry, research or teaching. A lot of the current physical chemistry research in industry and academia combines the techniques and ideas from several fields. For example, some chemists apply physical chemistry techniques to investigations of the mechanisms of organic reactions (what collisions and bond rearrangements occur, how fast are they, how many steps are there, etc.) - this type of study is called physical organic chemistry. Others apply physical techniques to the study of biological systems (why do proteins fold into the shapes that they have, how is structure related to function, what makes a nerve work, etc.) - this type of study is biophysical chemistry. Still others may use physical techniques to characterize polymers or study environmental systems.

 

 Branches of chemistry

The seven major types of chemistry categorize the study of matter into specific disciplines. While often overlapping, the seven branches are organic, inorganic, physical, analytical, biochemistry, nuclear, and environmental chemistry. 

• Organic Chemistry: Focuses on the structure, properties, and reactions of carbon-containing compounds
  . It is the foundation of pharmaceuticals, plastics, and fuels.
Inorganic Chemistry: Deals with the study of compounds that do not contain carbon-hydrogen bonds, such as metals, minerals, and organometallic substances.
Physical Chemistry: Applies physics to the study of chemistry. It investigates how matter behaves on a molecular and atomic level and how chemical reactions work in terms of energy, rate, and thermodynamics.
Analytical Chemistry: Involves the qualitative and quantitative analysis of materials to identify and separate components. It is crucial for forensic science, quality control, and ensuring food safety.
Biochemistry: The study of the chemical processes and substances that occur within living organisms. It bridges biology and chemistry to explain phenomena like genetics, metabolism, and disease.
Nuclear Chemistry: Focuses on the reactions and properties of atomic nuclei. This includes the study of radioactivity, nuclear power, and medical imaging technologies.
Environmental Chemistry: Studies the chemical and biochemical processes occurring in natural places. It monitors how human activities impact ecosystems, the atmosphere, and water supplies. 

Organic radicals and the theory of chemical structure

 Organic radicals and the theory of chemical structure

Both problems were finally resolved through the further development of organic chemistry. The leading organic chemists of the day were the German Justus von Liebig and the Frenchman Jean-Baptiste-André Dumas. In 1830 Liebig invented a device that made organic analysis rapid, convenient, and accurate, and his laboratory institute at the tiny University of Giessen in Hesse became the most famous chemical school in the world. Liebig taught an enormous number of chemists, and his students assisted in his research program. He was the leading figure in the rise of the research university and in the idea of a research group. As a professor at Giessen, and later at the University of Munich, he laid much emphasis on practical applications of chemistry, especially for physiology, agriculture, and consumer products. Dumas exerted a similar influence in France, training students and pursuing research at a private laboratory in Paris.

Both Liebig and Dumas initially accepted the Berzelian scheme and sought to understand organic molecules as composed of identifiable radicals held together electrochemically. The younger French chemists Auguste Laurent and Charles Gerhardt pursued chlorine substitution reactions and cast doubt on this simple model; sometime after 1840 Liebig and Dumas both retreated into positivism. In 1852 Liebig’s English former postdoctoral assistant Edward Frankland noticed a regularity in the combining capacity of the atoms of certain metals and semimetals. At about the same time, two former students of both Liebig and Dumas, Alexander Williamson in London and Charles-Adolphe Wurtz in Paris, were independently approaching the same idea from a different direction. Using a system of atomic weights and formulas developed by Gerhardt and Laurent—a modified version of Berzelius’s system that incorporated Avogadro’s ideas more consistently—they proposed that oxygen atoms could combine with two other simple atoms, such as hydrogen, or with two organic radicals and that nitrogen atoms could combine with three. This was the beginning of the concept of atomic valence.

In 1858 the young German theorist August Kekule then expanded this concept to carbon, not only proposing that carbon atoms were tetravalent but adding the idea that they could bond to each other to form chains, comprising a molecular “skeleton” to which other atoms could cling. Kekule’s theory of chemical structure clarified the compositions of hundreds of organic compounds and served as a guide to the synthesis of thousands more. (The self-chaining of carbon atoms was independently developed by the Scottish chemist Archibald Scott Couper.) This theory experienced dramatic expansion when Kekule successfully applied it to aromatic compounds (after 1865) and after Jacobus Henricus van ’t Hoff of the Netherlands and Joseph LeBel of France independently began to investigate molecular structures in three dimensions—later called stereochemistry.

Atomic and molecular theory

 Atomic and molecular theory

Lavoisier’s set of chemical elements, and the new way of understanding chemical composition, proved to be invaluable for analytic and inorganic chemistry, but in a real sense the chemical revolution had only just begun. Around the turn of the century, the English Quaker schoolteacher John Dalton began to wonder about the invisibly small ultimate particles of which each of these elemental substances might be composed. He thought that if the atoms of each of the elements were distinct, they must be characterized by a distinct weight that is unique to each element. Although these atoms were far too small to weigh individually, he realized that he could deduce their weights relative to each other—the ratio of the weight of an atom of oxygen to one of hydrogen, for instance—by examining reacting weights of macroscopic quantities of these elements. In fact, the laws of stoichiometry (combining weights of elements) were just then being developed, and Dalton used these regularities to justify his inferences. His first discussion of these issues dates to 1803, and he presented his atomic theory in the multivolume New System of Chemical Philosophy (1808–27).

Dalton’s atomic theory was a landmark event in the history of chemistry, but it had a crucial flaw. His procedure required that one know the formulas of the simple compounds resulting from the combination of the elements. For example, analytical data of that day indicated that water resulted from the combination of seven parts by weight of oxygen with one part of hydrogen. If the resulting water molecule was HO (one atom of each element combining to form a molecule of water), then the weight ratio of the atoms of these elements must be the same, seven to one. However, if the formula were H2O, then the weight of an oxygen atom would have to be 14 times the weight of a hydrogen atom. There was simply no way to determine molecular formulas at that time, so Dalton made assumptions based on the simplicity of nature. He chose HO as his water formula and, therefore, seven as the relative atomic weight of oxygen.

In the following years, several leading chemists adopted essential elements of Dalton’s theory, but many objected to the hypothetical elements just described; some also doubted the very possibility of investigating the world of the invisibly small. In 1808 the French chemist Joseph-Louis Gay-Lussac discovered that when gases combine chemically, they do so in small integral multiples by volume. Three years later the Italian physicist Amedeo Avogadro argued that this fact suggested that equal volumes of gases contain equal numbers of constituent particles (Avogadro’s law), physical conditions being the same. This idea provided a physical method of determining certain molecular formulas. For instance, Gay-Lussac had pointed out that exactly two volumes of hydrogen combine with precisely one of oxygen to form water. If Avogadro was right, the formula for water had to be H2O. But this line of reasoning also led to the uncomfortable notion that elementary gases had polyatomic molecules (O2, H2, and so on), and therefore many chemists rejected Avogadro’s hypotheses.

By far the greatest of the early atomists was the Swede Jöns Jacob Berzelius, who accepted parts of Avogadro’s ideas and developed an elaborate version of chemical atomism by 1826. It was Berzelius who in 1813 had proposed the alphabetic system for denoting elements, atoms, and molecular formulas, and the use of formulas as an aid for studying chemical composition and reactions began to blossom about 1830. However, different chemists were still making different assumptions regarding the formulas of simple compounds such as water, and so, for decades, various inconsistent systems of atomic weights and formulas were in use in the various European countries.

Berzelius also developed a theory of chemical combination based on the electrochemical studies that the invention of the battery (1800) had spawned. He became convinced that all molecules were held together by the Coulomb force, the electrostatic attraction between oppositely charged objects. (Berzelius assumed that a molecule’s constituent atoms or groups of atoms were not neutral, and he called these charged components radicals.) This theory of electrochemical dualism worked well with inorganic compounds, but organic substances seemed anomalous. Particularly in the 1830s, when chemists learned how to replace the hydrogen of organic compounds with chlorine atoms, Berzelius’s theory appeared to be threatened—after all, hydrogen and chlorine had opposite electrochemical characteristics, yet the substitution seemed to make little difference in the properties of the compounds. In the 1840s and ’50s, extensive debates over rival systems of chemical atomism and over electrochemical dualism enlivened the journal literature.