RCH2G Primary R2CHG Secondary R3CG Tertiary. 4.7 Preparation of Alkyl Halides from Alcohols and Hydrogen Halides R-OH + H-X -> R-x +HOH “Alcohol” + “Hydrogen halide” -> “Alkyl halide” + “Water” The more primary the alcohol the more reactive, Primary=any halide Secondary=usually just Br with heat 4.8 Mechanism of the Reaction of Alcohols with Hydrogen Halides: Hammond’s Postulate Reaction of alcohol with hydrogen halide is a substitution Hydrogen Halide protenates Alcohol which then goes to H2O and the positive “alcohol” (no longer an alcohol since missing OH group) joins with the Halide Electrophile: electron loving Nucleophile: Nucleus seekers (extra electron pair) 4.9 Potential Energy Diagrams for Multistep Reactions: The SN1 Mechanism SN1 Mechanism: slow step is unimolecular 4.10 Structure, Bonding, and Stability of Carbocations Primary Carbocations do not exist in intermediates since too unstable (H3C)-C(H2) and (H3)-C are even more unstable. Secondary (H3C)2-C(H) are possible particularly with secondary alcohols with hydrogen
57 (1) (iii) A triglyceride is also formed in the reaction between glycerol and three molecules of oleic acid, C17H33COOH. State and explain which of the two triglycerides (the one formed from stearic acid or the one formed from oleic acid) has the higher melting point. (the one from) stearic acid; saturated / no (C to C) double bonds; chains pack close together / stronger intermolecular forces / van der Waals’ forces etc; 3 Ignore hydrogen bonding. If wrong choice made, only third mark can be scored. (3) (b) An oil sample containing 0.0100 mol of oil was found to react with 7.61 g of iodine, I2.
Also, we will discover its regiochemistry and stereochemistry. Hydration reaction is a process that gives a alcohol functional group and a hydrogen to a carbon-carbon double bond of an alkene. According to Markovnikov's rule the -OH group will be attached to the most substituted carbon which is a carbon connected to the most branches. As the result, in normal hydration reaction of (+)-α-Pinene, the -OH group will attach the carbon attaching to a methyl group. However, the desired product is (-)-Isopinocampheol, in which the -OH group need to attach to the less substituted carbon instead.
Carboxylic acid to ketone, formation of acetal Which involves nitrile? R-MgX, H3O+, formation of cyanohydrin Which involve lithium? * Dithiane to Ketone (BuLi) * Carboxylic Acid to Ketone (Li-R) * Gilman/Acid Chloride to Ketone (R2CuLi) * Acid Chloride to Aldehyde (LiAlH(O-t-Bu)3 * Reduction of aldehydes, ketones, carboxylic acids (LAH) * Reduction of alcohol (TsCl, LAH) Aldehydes are more reactive than ketones Aldehydes and ketones have high bp but lower than alcohol Nomenclature: * Aldehyde: -al, as substituent: -formyl * Ketone: -one, as substituent: - oxo 0.9, 1.3, 1.4, 2.1, 2.5, * CH3, CH2, CH, COCH3, C---CH 3-4, 5-6, 1.7, 7.2, 2.3, * CH2X, C=CH2, C=CCH3, Ph-H, Ph-CH3 9-10, 10-12, 2-5, 4-7, 1.5 – 4 * Aldehyde, Carboxylic acid, R-OH, Ar-OH, R-NH2 O-H = 3300 N-H = 3300 C=O = 1700 C=C = 1660 IR Trends: * Ketones carbonyl frequencies are lower than aldehydes because conjugation * Conjugation lowers frequencies * Ring strain increases it HNMR trends: Ketone protons are lower than Aldehyde protons MS: * M+ peak is total * 15 = methyl * 29 = ethyl * 43 =
This process is fractional distillation. c) Some properties of hydrocarbons depend on the size of their molecules. These properties influence how hydrocarbons are used as fuels. boiling points viscosity flammability. C1.4.3 Hydrocarbon fuels Additional guidance: a) Most fuels, including coal, contain carbon and/or hydrogen and may also contain some sulfur.
Citric acid occurs in the matrix of the inner membrane of the mitochondrial. Citric acid starts after the glycolysis cycle produces the acetyl CoA compound and passes down two of the pyruvic acid molecules into the citric acid cycle. The acetyl CoA are broken down into carbon dioxide molecules with the formation of the two carbon dioxide molecules per each acetyl CoA, one ATP molecule is also made. • What is the role of the electron transport system? Include the reactants and the products.
In the experiment a secondary alcohol (cyclohexanol) is heated with acid (phosphoric acid). A carbocation is generated by the loss of water from cyclohexanol because of the protonated alcohol. Loss of hydrogen ion from the carbocation will give the desired alkene (cyclohexene). Fractional distillation is used to separate liquids that have different boiling points that are relatively close together. By using this method of distillation a mixture is heated to a temperature at which several fractions of the compound is evaporated the distillate is then condensed and collected.
As long as the electronegativity difference is no greater than 1.7, the atoms can only share the bonding electrons. An example of a covalent bond would be water, its two hydrogen atoms with one oxygen atom (H2O). If two atoms differ considerably in their electronegativity than one of the atoms will lose its electron to the other atom. This results in a positively charged ion (cation) and negatively charged ion (anion). The bond between these two ions is called an ionic bond.If the electronegativity difference is greater than 1.7 then the higher electronegative atom has an electron attracting ability which is large enough to force the transfer of electrons from the lesser electronegative atom.
Another means of classification depends on the type of bonding that exists between carbons. Hydrocarbons which contain only carbon-to-carbon single bonds are called alkanes. These are also referred to as saturated molecules. Hydrocarbons containing at least one carbon-to-carbon double bond are called alkenes, and those compounds with at least one carbon-to-carbon triple bond are called alkynes. These are compounds that are referred to as unsaturated molecules.
Introduction Nucelophilic substitutions are chemical reactions in which an electron rich nucleophile attacks the electron poor electrophile1. There are two classes of nucelophilic reactions – SN1, and SN2. The SN1 reaction is a 2 step, uni-molecular reaction, which is independent of the nucleophile. It requires a highly substituted electrophile since there is a formation of a carbocation in its rate determining step, good polar protic solvents which stabilize the carbocation and a good leaving group1. On the other hand, a SN2 reaction is a concerted, bimolecular reaction which has one slow, transition state1.