ABSTRACT The Diels-Alder reaction has been an area of great research interest with regards to enhancing enantioselectivity in the reaction by use of various catalysts and reaction conditions. INTRODUCTION In organic chemistry, a Diels-Alder reaction refers to a 4, 2 cycloaddition between a diene consisting of alternating double bonds and a substituted alkene (the dienophile) resulting in a substituted cyclohexene system. The reaction is often used to reliably control regioselective and enantioselective aspects in organic synthesis. If specific conditions are applied, these reactions can be reversible, with the reverse reaction referred to as the retro-Diels-Alder reaction. Mechanism, Regioselectivity and Enantioselectivity of the Diels-Alder Reaction
The Wittig reaction is valuable reaction. It has unique properties that allows for a carbon=carbon double bond to form from where a C=O double bond used to be located. Creating additional C=C double bonds is valuable due to its use in synthesis. The Wittig reaction will allow the synthesis of Stilbene (E and Z) from a Benzaldehyde (Ketcha, 141). One purpose of a Wittig reaction is the formation of alkenes from aldehydes or ketones employing a carbo-phosphorous ylide, which is stabilized vie resonance to allow for the carbon bonded to phosphorus to be deprotonate from by a base (Ketcha, 142).
The possible explanations and changes to make are similar to the previous questions. Conclusion and Future Experiment 18. The identity of the product and unknown were 4-tert-butylbenzyl phenol ether and tert-butyl phenol respectively. The key to making this discovery was the melting point and TLC results! The substitution reaction was successful but not fully effective.
Free radicals, acknowledged in chemistry since the birth of the 20th century, were originally used to describe common compounds in organic and inorganic chemistry, and several chemical definitions for them were suggested. Only in 1954 when the pioneering work of Daniel Gilbert and Rebecca Gersham was published (Gilbert DL (ed. ), 1981) were these radicals proposed as important players in biological environments and responsible for destructive processes in the cell. After which, in 1956, Herman Denham (Harman D, 1956) suggested that these species might play an important role in physiological events especially in the aging process (Harman D, 1981). His hypothesis, the free-radical theory of aging, inspired various studies and research efforts
Kolbe-Schmitt Reaction Kira Wall (CHE433) 12-3-14 The Kolbe-Schmitt reaction is named after Hermann Kolbe and Rudolf Schmitt. Schmitt published his research in the Journal fur Pracktische Chemie in 1885 while Kolbe published his research in the Annalen der Chemie und Pharmacie in 1860. The reaction adds a carboxyl group onto the benzene ring of a phenol. The process uses a base carbon dioxide and acid work-up. The original reaction done by Kolbe involved the formation of sodium phenoxide through the evaporation of a molar equivalent mixture of phenol and aqueous sodium hydroxide.
Introduction: We have seen that the carbonyl group of aldehydes and ketones is highly immediate, and that accompaniments to this functionality are ordinary. Carbonyl functionality reactive but that it also activates to hand carbon-hydrogen bonds (particularly alpha hydrogen’s) to go through a variety of substitution reactions.1 Carbonyl compounds can be explained by just four fundamental reaction types: Nucleophilic additions Nucleophilic acyl substitutions α-Substitutions Carbonyl condensations2 α-Substitutions: Alpha-substitution reactions take place at the site next to the carbonyl group the α-position and occupy the substitution of an α hydrogen atom by an electrophile, E,
Ion Exchange Chromatography is a technique for ionic separation based on exchange with resins in stationary phase and the eluents in mobile phase. These stages are based on the exchanges in an anion column to attract anions or in a cation column to attract cations. cations. A column measures the conductivity of a particular ion based on its affinity/attraction to it. The speed of movement of ions through the ion chromatograph columns depends not only on the diameter of the column but basically on the affinity of the ion to the specific resin or elute selected, the size of the interacting molecules and also the resultant distance between them based on the degree of attraction and repulsion.
He predicted the discovery of more elements, and left spaces open in his periodic table for them. In 1894, Sir William Ramsay and Lord Rayleigh discovered the noble gases. The noble gases group was then incorporated into the periodic table. In 1897 physicist J. J. Thomson first discovered electrons; small negatively charged particles in an atom. John Townsend and Robert Millikan later on were able to determine their exact charge and mass.
1.1 Kinetic model To determine the second order reaction rate constant of Acesulfame K with the different transient species studied, two pairs of independent competition kinetics were established for each transient: Acesulfame K with Ibuprofen and Acesulfame K with Atrazine. Assuming the first pair of competition for the hydroxyl radical generated by NaNO3 irradiation is Acesulfame and Ibuprofen (ACE, IBP). Their respective reaction rates are (M s-1): (Eq. 6) (Eq. 7) With k and k’ the second order reaction rates of Ace and IBP with HO•.
Properties of Ionic and Covalent Substances Lab Report Introduction The purpose of this lab was to determine which of the following substances: wax, sugar, and salt, are an ionic compound and which are a covalent compound. In order to accurately digest the experiments results, research of definitions of each relating led to the following information: ionic compounds are positive and negatively charged ions that experience attraction to each other and pull together in a cluster of ionic bonds; they are the strongest compound, are separated in high temperatures, and can be separated by polar water molecules. A covalent compound forms when two or more nonmetal atoms share valence electrons; covalent compounds are also
Literature review A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are shared pairs and bonding pairs, and the stable balance of attraction and a repulsive force between atoms, when they share electrons is called covalent bonding. Covalent bonding occurs when atoms share pairs of electrons. Another type of bonding is called a metallic bond. A metal bond is different form covalent and ionic bonds,
Polarity shared electrons get pull away difference in electrical charge at one end as opposed to the other end 2.3 The Ionic Bond 1. Ionic bonding when the electronegativity differences between 2 atoms were so extreme that the electrons were pulled off 1 atom only to latch on to the atom that was attracting them A: What is an Ion? 1. Ion is a changed atom or an atom with the number of electrons different from it number of protons 2. Ionic bonding is the chemical bonding in which 2 or more ions are linked by virtue of its opposite charge 3.