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Benzimidazoe Lab Report

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(vi). Initial addition of one of the products, viz. benzimidazole, to the reaction mixture does not affect the rate. (vii).The reaction rate is not altered significantly with the addition of nickel chloride, a typical chlorine scavenger. (viii). Polymerization is not observed when acrylonitrite is added to the reaction mixture. (ix). Oxidation of substituted benzyl alcohols by CBI has been investigated under comparable conditions. All the substrates follow the same kinetic behaviour as for the parent substrate. Electron donating groups increased the rate while electron withdrawing groups decreased the rate of oxidation (Table.2). The order of reactivity of substituted benzyl alcohols with CBI is p-OCH3 > p-CH3 > m-OCH3 > H > p-Br > p-Cl > m-CH3 > m-NO2 > m-Cl > m-Br > p-NO2 (x). Activation and thermodynamic parameters have been calculated for benzyl alcohol and substituted benzyl alcohols (Table. 3). The reaction rates are governed by the changes in both the enthalpy and entropy of activation. This is further supported by the lower values of Ea. The negative values of ∆S# imply the formation of an ionic …show more content…

The negligible electrolytic effect observed for the reaction substantiates the reaction between an ionic species and a neutral molecule in step 2. Further the participation of water molecule in the rate determining step is confirmed by Bunnet – Olsen plot giving a slope value ɸ= 1.30 which is in good agreement with the slope value ɸ = 1.40 for the oxidation of benzyl alcohols by CBT [33]. This clearly indicates that a proton transfer by water molecule occurs in the rate determining step leading to the formation of benzyl hypochlorite intermediate [49]. Hypohalites are known to decompose to carbonyl products [50&51]. Therefore the following scheme has been proposed for the oxidation of benzyl alcohol by

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Experiment 2 Report Scaffold (Substitution Reactions, Purification, and Identification) Purpose/Introduction 1. A Sn2 reaction was conducted; this involved benzyl bromide, sodium hydroxide, an unknown compound and ethanol through reflux technique, mel-temp recordings, recrystallization, and analysis of TLC plates. 2. There was one unknown compound in the reaction that was later discovered after a series of techniques described above.

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It is understood the mechanism is acid-catalyzed where protons coordinate with the carbonyl oxygen to make the carbonyl carbon more electropositive for nucleophilic attack (Scheme 1). In the experimental procedure all reactants were added together, this is inefficient as the protons can coordinate with either trans-cinnamic acid or methanol. Coordination with methanol is unnecessary as it reduces its nucleophilicity and makes less protons available to coordinate with the carboxylic acid. To improve

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In this lab, the purpose of the oxidation/Wittig “Domino” reaction was to be able to perform an oxidation reaction quickly by performing a one-pot reaction rather than adding another purification step. In the first step of the process, pyridinium chlorochromate (PCC) is the oxidizer to the benzyl alcohol. However, the PCC needs to be buffered with sodium acetate to negate PCC’s acidic properties that may affect the further reaction(5) which was done in a solution in DCM. The Wittig

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In the article, Rhodacarboranes as catalysts for oxidative coupling of benzoic acid with diphenylacetylene, it has proven that the reactions catalyzed by [CpRhI2]2 afford the product in 90% yields.2 Furthermore, in the book, Science of Synthesis: Houben-Weyl Methods of Molecular Transformations, 1, 2, 3, 4-tetraphenylnaphthalene yield 80% when synthesized by a palladium-catalyzed reaction.3 In both cases, it has proven that the use of catalyst is common to give higher yield of 1, 2, 3, 4-tetraphenylnaphthalene. Catalyst does not increase the yield, but it helps lower the activation energy of the reaction, allowing the reaction to proceed

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The main objectives of the experiment were the following: to synthesize isoborneol, recrystallize the product, characterize it, and determine the yield of the product. To synthesize isoborneol, the reduction of camphor by reducing agent, sodium borohydride (NaBH4), was carried out (Figure 1). The utilized NaBH4 was determined to be active based on the bubbling observed in the reaction mixture. The bubbling is due to the evolution of hydrogen gas from the reaction of NaBH4 and methanol (Equation 1; Davis&Gotthbrath, 1962). NaBH4 + 4 CH3OH→ NaB(OCH3)4 + 4H2

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The purpose of this experiment was to learn about the electrophilic aromatic substitution reactions that take place on benzene, and how the presence of substituents in the ring affect the orientation of the incoming electrophile. Using acetanilide, as the starting material, glacial acetic acid, sulfuric acid, and nitric acid were mixed and stirred to produce p-nitroacetanilide. In a 125 mL Erlenmeyer flask, 3.305 g of acetanilide were allowed to mix with 5.0 mL of glacial acetic acid. This mixture was warmed in a hot plate with constantly stirring at a lukewarm temperature so as to avoid excess heating. If this happens, the mixture boils and it would be necessary to start the experiment all over again.

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Tetraphenylcyclopentadienone (0.100 g, 0.260 mmol), dimethyl acetylenedicarboxylate (0.1 mL), and nitrobenzene (1 mL) were placed in a small reaction tube along with a boiling stick. The reaction tube was heated to a reflux using a sand bath until the purple soln. turned a tan color. When the soln. was warm to touch, ethanol (3 mL) was stirred in.

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In this experiment, racemic 2-methylcyclohexanone was reduced using sodium borohydride as a nucleophile to give a diastereomeric mixture of cis and trans secondary alcohols. The products were analyzed for purity using IR spectroscopy and gas chromatography. 1.2 g of 2-methylcyclohexanone and 10 mL of methanol were combined in a flask and cooled in an ice bath. Two 100 mg portions of sodium borohydride were added to the flask and stirred. 5 mL of 3M sodium hydroxide, 5 mL of de-ionized water, and 15 mL of hexane were added to the reaction flask and stirred.

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In this oxidation benzoin to benzil experiment, students placed 1.0g of benzoin from the previous lab with 0.50g of ammonium nitrate in round bottom flask. Nitrate in ammonium nitrate can regenerate from Cu+ to Cu2+ after finished first oxidized benzoin. Then, add 4.0ml of glacial acetic acid and 1.0ml of 2% cupric acetate as

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In the presence of a nucleophile and good leaving group, an organic reactant in specific conditions is likely to undergo a chemical reaction, namely, nucleophilic substitution. Nucleophilic substitution consists of two different mechanisms, SN1 and SN2. In this experiment, SN2 is the mechanism tested. SN2 is a relatively fast, one-step mechanism in which the nucleophile attacks the organic reactant and the leaving group diverges from the reactant to become a weak base (Fig. 1). The overall speed of the reaction can increase based on the size or basicity of the nucleophile, or the bulkiness of the carbon group with the leaving group.

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Aims of experiment • Determine the rate constants for hydrolysis of (CH3)3CCl in solvent mixtures of different composition (50/50 V/V isopropanol/water and 40/60 V/V isopropanol/water) • Examine the effect of solvent mixture composition on the rate of hydrolysis of (CH3)3CCl Introduction With t-butyl chloride, (CH3)3CCl, being a tertiary halogenoalkane, it is predicted that (CH3)3CCl reacts with water in a nucleophilic substitution reaction (SN1 mechanism), where Step 1 is the rate-determining step. The reaction proceeds in a manner as shown

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This paper talks about what effect the reaction speed when 2,4-dinitrophenol (24-DNP) is going to be decomposed by nature light. In an aqueous environment, decomposition speed of 24-DNP is significantly slower than which dissolved in secondary organic material (SOM) which generated through a-pinene. Low temperature also do great effect to this reaction in organic solvent. Author make a assumption that the increase of viscosity,due to low temperature, suppresses the moment of atom reaction. The temperature, the matrix structure and the viscosity are first time be reported.

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Purpose/Introduction The process of recrystallization is an important method of purifying a solid organic substance using a hot solution as a solvent. This method will allow the separation of impurities. We will analyze Benzoic Acid as it is dissolved and recrystallized in water and in a solvent of Methanol and water. Reaction/Summary

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Abstract The unknown concentration of benzoic acid used when titrated with standardized 0.1031M NaOH and the solubility was calculated at two different temperatures (20◦C and 30◦C). With the aid of the Van’t Hoff equation, the enthalpy of solution of benzoic acid at those temperatures was determined as 10.82 KJ. This compares well with the value of 10.27KJ found in the literature.

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