1900 Grignard begins to use RMgX compounds to add carbons in synthesis organic chemistry
1901 Hopkins discovers first essential amino acid: tryptophan bio/medicinal chemistry
1902 Fischer, Hofmeister: polypeptides and proteins consist of amino acids bio/medicinal chemistry
1903 Nernst discovers buffers solution chemistry
1904 Abegg: rule of 8 atomic/molecular structure
1905 Hahn discovers Pb to be the ultimate product of uranium decay nuclear chemistry
1906 Harden: enzymes catalyze fermentation bio/medicinal chemistry
1907 Fischer synthesizes peptides& compares them to digestive products bio/medicinal chemistry
1907 Boltwood uses U/Pb (see 1905) to date billion year rocks nuclear chemistry
1908 Haber process of producing ammonia from air and hydrogen industrial inorganic chemistry
1908 Baekeland invents Bakelite: first plastic polymer chemistry
1908 Brandenburger invents cellophane polymer chemistry
1908 Perrin calculates Avogadro's number based on Einstein's paper on Brownian motion; molecular theory becomes stronger solution chemistry
1909 Benedictus invents safety glass polymer chemistry
1909 Hoffamn produces synthetic rubber from butadiene polymer chemistry
1909 Sorenson develops pH scale solution chemistry
1910 Staudinger synthesizes isoprene organic chemistry
1911 Rutherford proposes nuclear model of the atom atomic/molecular structure
1911 Levene discovers ribose and RNA bio/medicinal chemistry
1912 Von Laue begins x ray crystallography atomic/molecular structure
1912 Hopkins discovers that vitamins are essential for health bio/medicinal chemistry
1912 Panet and Hevesy develop radioactive tracers for molecular reactions nuclear chemistry
1913 Bohr proposes energy levels for electrons atomic/molecular structure
1913 William and Lawrence Bragg: Bragg's law later helps in determining molecular structure with x rays atomic/molecular structure
1913 McCollum and Funk discover vitamins A and B (1912), respectively bio/medicinal chemistry
1913 Soddy proposes isotope theory nuclear chemistry
1913 Moseley shows relationship between x ray wavelength and atomic number nuclear chemistry
1913 Bergius uses pressure and H2 to convert coal into petrol and kerosene petrochemistry
1913 Burton: thermal cracking methods double amount of petrol from crude oil petrochemistry
1916 Lewis: valence theory of bonding atomic/molecular structure
1918 mass spectrometer invented by Aston: allows isotopic ions to be separated nuclear chemistry
1919 Aston discovers that mass number is whole number sum of protons and neutrons nuclear chemistry
1919 Using a mass spectrometer (which was a spinoff of his classic expt. that led to electron's m/e, Thomson shows that stable elements also have isotopes nuclear chemistry
1920 McCullum discovers vitaminD; other team discovers vitamin D-sunlight connection bio/medicinal chemistry
1921 Midgley: uses tetraethyl lead as antiknocking agent; compound is later banned fifty years later petrochemistry
1922 Staudinger: rubber discovered to be natural polymer, a macromolecule organic chemistry
1923 Bronsted and Lowry independently propose acid base theory based on protons solution chemistry
1925 Pauli: no two electrons can have identical sets of quantum numbers atomic/molecular structure
1925 Mb and Rh are discovered by a German team new elements
1926 First enzyme is crystallized: urease bio/medicinal chemistry
1927 Sidgwick: modern valence theory relates valence to outershell number of electrons atomic/molecular structure
1928 Gyorgyi isolates Vitamin C bio/medicinal chemistry
1928 Diels and Alder introduce way of synthesizing cyclic carbon compounds from dienes organic chemistry
1928 German and American companies invent PVC = polyvinyl chloride polymer chemistry
1929 Fleming discovers penicillin bio/medicinal chemistry
1929 Levene discovers deoxyribose and DNA bio/medicinal chemistry
1929 Houdry develops catalytic method of cracking crude oil; important to plastics industry petrochemistry
1930 Debye uses x rays to obtain interatomic distances and molecular structure atomic/molecular structure
1930 Midgley: synthesizes the first Freon, which soon became the universal coolant in appliances but which in the 1970's was linked to ozone destruction industrial organic chemistry
1930 Chalmers invents acrylic plastic(plexiglas) polymer chemistry
1930 Tiselius discovers electrophoresis solution chemistry
1931 Urey and Washburne discover deuterium from noting higher density of electrolyzed water nuclear chemistry
1932 Krebs discovers urea cycle bio/medicinal chemistry
1932 Domagk synthesizes the first sulfa drug bio/medicinal chemistry
1932 Chadwick discovers the neutron nuclear chemistry
1932 Dupont produces neoprene(polychloropene): first commercial synthetic rubber polymer chemistry
1933 Huckel and Coulson independently develop molecular orbital theory atomic/molecular structure
1933 Richard Kuhnis isolates and determines structure of ribovlavin(vitamin B2) bio/medicinal chemistry
1933 King determines structure of vitamin C; names it ascorbic acid; Hawaorth ad Reichstein independently synthesize it bio/medicinal chemistry
1934 Frederic and Irene Curie use alpha particle sto create first artificial radioactive isotopes nuclear chemistry
1934 Fermi proposes -decay theory, coalescing previous work on neutrino. Later demonstrated that transformation occurs in almost every element subjected to neutron bombardment. nuclear chemistry
1934 Carothers develop polyamide based nylon polymer chemistry
1935 Stanley discovers that viruses are not organisms bio/medicinal chemistry
1935 Kendall isolates cortisone form adrenal cortex bio/medicinal chemistry
1935 Dempster synthesizes U235-fissionable version of uranium nuclear chemistry
1935 Polyethylene synthesized by Michael Perrin polymer chemistry
1936 Vitamin E is isolated by Evans. Oliver and Emerson bio/medicinal chemistry
1936 Gamow and Teller develop theory of beta decay nuclear chemistry
1936 Sun Oil Co, introduces catalytic cracking petrochemistry
1937 Krebs discovers citric acid cycle bio/medicinal chemistry
1937 Elvehjem discovers niacin (B3), which prevents pellagra bio/medicinal chemistry
1937 Using deuterium and molybdenum Segre and Perrier create first element in lab: technetium nuclear chemistry
1937 Dow begins production of polystyrene polymer chemistry
1938 Plunkett discovers tetrafluoroethylene (Teflon) polymer chemistry
1939 Pauling applies quantum mechanics to chemical bond atomic/molecular structure
1939 Doisty find structure of Vitamin K and synthesizes it bio/medicinal chemistry
1939 Muller synthesizes DDT industrial organic chemistry
1939 Fluidized bed catalytic cracking of petroleum discovered by Lewis and Gilliand of M.I.T. Still used today petrochemistry
1940 Kamen discovers carbon 14 nuclear chemistry
1940 Dunning used diffusion to isolate U-235 fluorides of uranium nuclear chemistry
1941 Lepmann discovers coenzyme A; shows that it is involved in the acetylation of choline, in synthesis of citrate and acetoacetate, and in pyruvate and fatty acid metabolism. bio/medicinal chemistry
1943 Silicone rubber is developed polymer chemistry
1944 Avery, Macleod and McCarthy demonstrate role of DNA in inheritance bio/medicinal chemistry
1944 Woodward and Doering synthesize quinine organic chemistry
1946 Carbon 13 is discovered and used to treat metabolic diseases bio/medicinal chemistry
1946 Purcell and Bloch independently develop nmr, an important analytical tool in organic chemistry organic chemistry
1947 Todd synthesizes ATP bio/medicinal chemistry
1947 Libby develops carbon 14 dating nuclear chemistry
1948 Feynman, Schwinger and Tomonoga independently develop quantum electrodynamics nuclear chemistry
1948 Aldrich and Nier establish basis for potassium argon dating nuclear chemistry
1949 Hodgkin uses x ray crystallography to determine structure of penicillin atomic/molecular structure
1951 Pauling and Corey determine structure of spiral proteins bio/medicinal chemistry
1951 Woodward synthesizes cortisone organic chemistry
1952 Franklin discovers sugar-phosphate backbone of DNA lies on the outside of the molecule. She discovers the helical structure of DNA has two strands. bio/medicinal chemistry
1953 Watson and Crick elucidate rest of structure of salt of DNA molecule and suggest method of replication bio/medicinal chemistry
1954 Wittig:used phosphorus ylides to create alkenes from carbonyl containing compounds organic chemistry
1954 Woodward synthesizes lysergic acid and highly complex strychnine organic chemistry
1954 Natta: obtains polypropylene using stereospecific catalysts polymer chemistry
1955 Hodgkin determines structure of vitamin B12 using xray crystallography bio/medicinal chemistry
1956 Kornberg synthesizes DNA and discovers that bacteria use DNA polymerase bio/medicinal chemistry
1957 Brown synthesizes organoboranes which are used to create organic acids and ketones organic chemistry
1959 Peruts determines structure of hemoglobin bio/medicinal chemistry
1960 Woodward an Strell independently synthesize chlorophyll organic chemistry
1961 Crick and Brenner realize that DNA base triplets code for amino acids bio/medicinal chemistry
1961 Jacob and Monot discover messenger RNA, the molecule that transfers genetic information form DNA to the site of protein synthesis bio/medicinal chemistry
1967 Pederson discovers Crown ethers organic chemistry
1968 DENDRAl computer system for identifying compounds from mass spectra organic chemistry
1969 Hodgkin finds the structure of insulin, allowing it to be synthesized in the laboratory bio/medicinal chemistry
1971 Woodward synthesizes vitamin B12; work led to symmetry theory for pericyclic reactions involving cyclic transition state organic chemistry
1973 Cohen and Boyer develop recombinant DNA technique and move snippets of DNA across species bio/medicinal chemistry
1974 Molin, Rowland and Crutzen warn public about dangers of CFC's environmental chemistry
1977 Sanger sequences entire DNA of virus phiX174 using gel electrophoresis bio/medicinal chemistry
1981 Michel and Reveau prepare superconducting mixture that works at relatively high temperatures materials chemistry
1985 Kroto, Curl and Smalley discover fullerenes organic chemistry