Discover Investigator

When the lithium phases were discovered, investigations were started in the lithia-soda system to determine if zeolites of intermediate composition could be synthesized. A 1 1 ratio of lithia to soda was used in all batch compositions. Silicic acid, lithium hydroxide, sodium hydroxide, and aluminum hydroxide (Hydral 710) were the best combinations of... 

Studies of surfaces and surface properties can be traced to the early 1800s [1]. Processes that involved surfaces and surface chemistry, such as heterogeneous catalysis and Daguerre photography, were first discovered at that time. Since then, there has been a continual interest in catalysis, corrosion and other chemical reactions that involve surfaces. The modem era of surface science began in the late 1950s, when instmmentation that could be used to investigate surface processes on the molecular level started to become available. 

Merges has systematically investigated certain reaction schemes and their realization in chemistry, this led him to instances that were without precedent. He could then verify some of these experimentally and thus discover new reactions [22]. 

This preparation was discovered independently by Geuther (1863) and by Frankland and Duppa (1865). The reaction was subsequently investigated in detail and so w idely extended by Claisen that it has become solely a specific example of the more general process known as the Claisen Condensation. Claisen showed that an ester under the influence of sodium ethoxide would not only condense with itself (as in the preparation of ethyl acetoacetate), but also with (i) another ester, (ii) a ketone, if of formula RCHgCOR, (iii) a nitrile, if of formula RCH CN, in each case with the elimination of alcohol. Examples of these modifications are ... 

Gr. technetos, artificial) Element 43 was predicted on the basis of the periodic table, and was erroneously reported as having been discovered in 1925, at which time it was named masurium. The element was actually discovered by Perrier and Segre in Italy in 1937. It was found in a sample of molybdenum, which was bombarded by deuterons in the Berkeley cyclotron, and which E. Eawrence sent to these investigators. Technetium was the first element to be produced artificially. Since its discovery, searches for the element in terrestrial material have been made. Finally in 1962, technetium-99 was isolated and identified in African pitchblende (a uranium rich ore) in extremely minute quantities as a spontaneous fission product of uranium-238 by B.T. Kenna and P.K. Kuroda. If it does exist, the concentration must be very small. Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars. 

Gr. Tantalos, mythological character, father of Niobe) Discovered in 1802 by Ekeberg, but many chemists thought niobium and tantalum were identical elements until Rowe in 1844, and Marignac, in 1866, showed that niobic and tantalic acids were two different acids. The early investigators only isolated the impure metal. The first relatively pure ductile tantalum was produced by von Bolton in 1903. Tantalum occurs principally in the mineral columbite-tantalite. 

In one of the earliest mechanistic investigations m organic chemistry Arthur Lapworth discovered m 1904 that the rates of chlorination and brommation of acetone were the... 

Copper acetate, ferrous acetate, silver acetate [563-63-3] basic aluminum acetate, nickel acetate [373-02-4] cobalt acetate, and other acetate salts have been reported to furnish anhydride when heated. In principle, these acetates could be obtained from low concentration acetic acid. CompHcations of soHds processing and the scarcity of knowledge about these thermolyses make industrial development of this process expensive. In the eady 1930s, Soviet investigators discovered the reaction of dinitrogen tetroxide [10544-72-6] and sodium acetate [127-09-3] to form anhydride ... 

Oxygen Octahedra. An important group of ferroelectrics is that known as the perovskites. The perfect perovskite stmcture is a simple cubic one as shown in Figure 2, having the general formula ABO, where A is a monovalent or divalent metal such as Na, K, Rb, Ca, Sr, Ba, or Pb, and B is a tetra- or pentavalent cation such as Ti, Sn, Zr, Nb, Ta, or W. The first perovskite ferroelectric to be discovered was barium titanate [12047-27-7] and it is the most thoroughly investigated ferroelectric material (10). 

A reexamination of polycarbonate chemistry was carried out about 50 years after the first aromatic polycarbonates of resorcinol and hydroquinone were discovered. In independent investigations at Bayer AG and General Electric, it was discovered that the polycarbonates of BPA could be prepared (eq. 2). Unlike the ahphatic polycarbonates prepared earlier, which were either hquids or low melting sohds, the aromatic polycarbonates were amorphous sohds having elevated glass-transition temperatures. 

During the most active period of investigation of sulfanilamide derivatives, 1935—1944, for systemic bacterial infections, the antimycobacterial activity of 4,4 -dianainodiphenylsulfone [80-08-8] (DDS, dapsone) was discovered (14). Although neither this compound nor its derivatives proved to be clinically usehil for human tuberculosis, it did evolve into the most important type of compound for leprosy (15). The diacetyl derivative has also... 

In 1939 the isolation of a mixture of microbial products named tyrotbricin from a soil bacillus was described. Further investigation showed this material to be a mixture of gramicidin and tyrocidine. In rapid succession the isolation of actinomycin (1940), streptothricin (1942), streptomycin (1943), and neomycin (1949), produced by Streptomjces were reported and in 1942 the word antibiotic was introduced. Chloramphenicol, the first of the so-called broad spectmm antibiotics having a wide range of antimicrobial activity, was discovered in 1947. Aureomycin, the first member of the commercially important tetracycline antibiotics, was discovered in 1948. 

Sobering investigators uncovered a second significant breakthrough in microbial biotechnology of steroid production. They discovered that Corynebacterium simplex converted hydrocortisone (cortisol) (29) to prednisolone via a 1,2-dehydrogenation reaction. This A -3-ketosteroid is a highly active antiinflammatory commercial product (162). 

In 1896, Becquerel discovered that uranium was radioactive (3). Becquerel was studying the duorescence behavior of potassium uranyl sulfate, and observed that a photographic plate had been darkened by exposure to the uranyl salt. Further investigation showed that all uranium minerals and metallic uranium behaved in this same manner, suggesting that this new radioactivity was a property of uranium itself In 1934, Fermi bombarded uranium with neutrons to produce new radioactive elements (4). 

The first observation of the enantioselective properties of an albumin was made in 1958 (28) when it was discovered that the affinity for L-tryptophan exceeded that of the D-enantiomer by a factor of approximately 100. This led to more studies in 1973 of the separation of DL-tryptophan [54-12-6] C22H22N2O2, on BSA immobilized to Sepharose (29). After extensive investigation of the chromatographic behavior of numerous racemic compounds under different mobile-phase conditions, a BSA-SILICA hplc column (Resolvosil-R-BSA, Macherey-Nagel GmvH, Duren, Germany) was... 

Methanation. Since 1902, when Sabatier discovered that carbon monoxide could be hydrogenated to methane [74-82-8] the methanation reaction (eq. 12) has been the subject of intense investigation (47,48) (see Hydrocarbons, C —C ). 

In the period following World War I and during World War II, a wide variety of sulfur analogues of mustard were investigated and many potent vesicants were discovered. Each had two 2-chloroethyi groups attached to a sulfur atom. Examples of such compounds are... 

The first synthetic dyestuff, mauveine, was discovered by Perkin in 1856 in the UK and led to many investigations of the derivatives of coal tar as potential coloring matters. The first dia2onium salt derived from picramic acid was prepared in 1858 and is still the basic chemistry behind coundess commercial products. Despite these inventions, in 1900 the vast majority of dyestuffs were still of natural origin. Now at the end of the century the situation has changed dramatically synthetic dyes dominate. 

It is not always practical or convenient to investigate corrosion problems in the laboratory. In many instances, it is difficult to discover just what the conditions of service are and to reproduce them exactly. This is especially true with processes involving changes in the composition and other characteristics of the solutions as the process is carried out, as, for example, in evaporation, distihation, polymerization, sulfona-tion, or synthesis. 

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