SYNT m o d u l a r · l a b o r a t o r y · p r o g r a m · i n · publisher: H. A. Neidig c h e m i s t r y 738 organic editor: Joe Jeffers Copper-Catalyzed Oxidation of Benzoin to Benzil prepared by Carl T. Wigal‚ Lebanon Valley College PURPOSE OF THE EXPERIMENT Oxidize benzoin to benzil using ammonium nitrate and copper(II) ion as a catalyst‚ monitoring the reaction by thin-layer chromatography. Characterize the product using melting point measurement and infrared spectroscopy. EXPERIMENTAL
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Introduction: The purpose of this experiment is to use sodium borohydride to reduce benzil. However‚ stereochemistry allows for five possible products. If only one carbonyl group is reduced during the reaction a racemic mixture of benzoin will be the product that is produced. After the first reduction a chiral center forms causing the second reduction to occur from only one side of the ketone. Depending on which side the second reduction take place there are three possible products including: a racemic
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Thiamine-Catalyzed Benzoin Condensation I.Conclusion Benzoin was produced by reacting 2 mols of benzaldehyde with the catalyst thiamine to form a new C-C bond. A total of 2.626 grams were recovered. There was a 33% recovery of benzoin. The low percent recovery could be due to the purity of the limiting reactant‚ benzaldehyde. Upon filtration‚ the mother liquid appeared oily making it more likely that the low recovery was due to the solution ‘oiling out.’ This could be avoided in the future
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Benzil Reduction Introduction The objective of the experiment was to reduce Benzil‚ using sodium borohyride as the reducing agent. In a benzil reduction‚ there are five possible products than can occur‚ specifically a racemic mixture of benzoin‚ racemic mixture of hydrobenzoin‚ or meso-hydrobenzoin. Therefore‚ three different tests were conducted in determining the identity of the product: melting point‚ thin light chromatography‚ and infrared spectroscopy. (a) Mechanism and reaction equation
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Synthesis of Benzoin Date of Experiment: 1-26-15 Chelsea Price Lab Partner: Joey Simmons Abstract: In this experiment‚ benzoin was synthesized from benzaldehyde‚ using thiamine hydrochloric acid as a catalyst. The thiamine HCl was deprotonated by sodium hydroxide and acted as a nucleophile to attack the benzaldehyde. A water-cooled condenser was used to heat the solution at reflux. Vacuum filtration was used to wash and dry the product. The benzoin product was recrystallized
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Sodium borohydride Reduction of Benzil Introduction: The Purpose of this experiment is for the students to learn how to use sodium borohydride to reduce benzil to its secondary alcohol product via reduction reaction. This two-step reaction reduces aldehydes by hydrides to primary alcohols‚ and ketones to secondary alcohols. In order for the reaction to occur and to better control the stereochemistry and yield of the product‚ the metal hydride nucleophile of the reducing agents such as LiH‚ LiAlH4
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procedure. Results and Analysis {Limiting reagent} Mass benzoin = 2.0050g (0.00945 mole) Mass sodium borohydride = 0.4059g (0.0107 mole) Mass compound A used to form compound B = 1.0647g Results Mass (g) moles Molecular formula Yield (%) Mp (pure) Compound A 1.7458 0.00815 C14H14O2 86.22 138-139 Compound C 0.4255 0.001988 C14H14O2 40.02 136-138 Spectral Analysis IR Absorption (cm-1) Assignment Benzoin 3411‚ 3374 OH 2961‚ 2903 C-H aromatic 2358 C-O
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Benzil is produced in the first step of this experiment’s multistep synthesis through the oxidation of benzoin. In order to produce the desired o-diketone‚ the alcohol on benzoin must be oxidized. Nitric acid was the oxidizing agent used in this experiment. As a result‚ the alcohol group on benzoin acted as the nucleophile and attacked the electrophilic nitrogen of nitric acid. As this step forms oxonium‚ excess water in the system deprotonated the oxonium to restore the neutral charge on oxygen
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Spectra Analysis Organic Chemistry Lab‚ CHEM 369 The University of Tennessee‚ Knoxville Dr. Smith Spectra 1: tert-butyl cyanoacetate Molecular formula: 141/13 = 10 R 11 => C10H10+11 => C10H21 C10H21NO2 – C3H10 = C7H11NO2 DBE: 2(#C - #H/2 - #X/2 + #N + 2)/2 =2(7 – 11/2 – 0/2 + 1 + 2)/2 = 3=> 1 double bond and 1 triple bond Mass spectrum table: m/z fragment |40
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material in the subsequent reaction. The multistep synthesis of benzilic acid begins with a conversion benzaldehyde to benzoin through a condensation reaction. The benzoin then oxidizes into benzil‚ which undergoes rearrangement to give benzilic acid. Benzoin Synthesis * When two benzaldehyde molecules condense in the presence of thiamine‚ it leads to the formation of a molecule of benzoin. The thiamine behaves as a coenzyme catalyst. This step of the reaction involves the addition of ethanol
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