Essay on Multistep Synthesis of Benzilic Acid - 2070 Words

Abstract: The objective of the experiment was to prepare Benzilic acid by multistep synthesis starting with benzaldehyde. In this setup however, product of the first step, Benzoin, is provided thereby omitting the first step involving the conversion of benzaldehyde. For this experiment, the microscale techniques of reflux, crystallization, and melting-point determination were used. Utilizing these techniques a product yield of 93% for benzil and 57% for Benzilic acid was obtained, as well as a melting point range of 94.8 – 95.4oC for benzil and 152.0 – 153.9oC for Benzilic acid. With the literature melting-point value of benzil being 95oC ( Pavia, 2012), the product was deemed of pure enough quality to be used in the preparation of†¦show more content†¦Procedure To prepare Benzil, .30g of Benzoin was placed in a 5-mL conical vial with 1.5mL of concentrated nitric acid. With the addition of a spin vane and attachment of an air condenser, the mixture was heated and stirred for an hour in a hot water bath at 70oC. The red nitrogen oxide gases were allowed to evolve completely before the air condenser was detached and the mixture was transferred to a beaker containing 4mL ice-cold water then cooled via ice bath. The crude product was then collected and washed with 5mL cold water through vacuum filtration. The weighed product was then transferred and dissolved with hot 95% ethanol in another flask over light heat. Once dissolved completely, the flask was removed from heat, seeded, and then allowed to cool first at room temperature, than in an ice-bath. Following crystallization, the product was collected and rinsed with 95% ethanol vacuum filtration for 5 minutes. After air-drying, the dry benzil was weighed and a melting point was taken. To rearrange into Benzilic acid, .100g of benzil and 95% ethanol was mixed into a 3mL conical vial. Following the addition of a spin vane and attachment of an air condenser, the mixture was heated with an aluminum block at 95oC. After dissolving completely, .25mL of aqueous potassium hydroxide was added and gently boiled at 110oC with stirring for 15 minutes. The brown mixture was transferred to a beaker,Show MoreRelatedMultistep Synthesis of Benzilic Acid2109 Words   |  9 PagesMulti-Step Synthesis of Benzilic Acid from Benzoin Abstract: The main purpose of this experiment was to convert a secondary alcohol to a ketone, utilizing a mild and selective oxidizing agent. In addition, this converted alpha diketone was then subjected to rearrangement to a carboxylate salt, then acidification, to produce an alpha-hydroxyacid. In this experiment, benzoin was used and converted into benzil, which was then used to synthesize benzillic acid. The yields were not ideal: .081g of benzil-Read MoreEssay about Synthesis of Benzilic Acid1107 Words   |  5 PagesSynthesis of benzilic acid from benzoin utilizing a multi-step reaction. Names: Arian Karim TA Name: Sayantan Das Lab Day amp; Time: Thursday 7:30-11:40 Lab Section #: Abstract The main purpose of this experiment was to synthesize benzilic acid from benzoin. This requires a multistep synthesis with benzyl as an intermediate product. The first step required HNO3 as an oxidizing agent and the second step required KOH and HCl. The percentage yields of benzil and benzilic acid were 59.5%