Multistep Synthesis of Benzyl Acid from BenzaldehydeCambria M. MillerMarch 24, 2014Texas A&M University at Galveston, Galveston, TexasINTRODUCTIONBenzylic acid (fig. 1) is a white crystalline solid often used in organic synthesis of some pharmaceutical products and medicines (1). It is believed that benzylic acid can be successful in anti-aging products. Benzyl acid is an alpha hydroxy acid, and other alpha hydroxy acids have been used in the same way (2). Figure 1. Structure of benzylic acid. The purpose of this experiment was to successfully synthesize benzylic acid from benzaldehyde. Benzaldehyde is an organic molecule used to produce bitter almond oil and to synthesize many different organic compounds (3). This experiment is a multistep synthesis, meaning there are multiple parts that require the product from the previous step to be used as a reactant in the next step. Therefore it is very important to achieve high yields and precision in each step. Traditionally cyanide has been used as a catalyst in this reaction since Von Liebig first discovered it in his research with almond oil. However, cyanide is very poisonous and harmful to health. More recently it has been discovered that vitamin B1, a coenzyme called thiamine hydrochloride, can be used to catalyze the condensation of benzoin, which is preferable to using cyanide. This experiment will test whether thiamine can effectively catalyze the reaction (2). The experiment begins with the condensation of benzoin (eq. 1). In the presence of the thiamine catalyst, the 2 molecules of benzaldehyde condense to produce benzoin when heated with sodium hydroxide and ethanol. Equation 1: condensation of benzoin. Benzyl production (eq. 2) is a redox reaction. The b... center of the paper... was cut in part C using the product from part B. Another source of error was that on two separate occasions recrystallization was omitted from the procedure. While this probably doesn't have a huge effect, the crystallization of the product helps eliminate impurities. The overall product yield for this reaction is 90.53%. While this number seems high, indicating a very successful synthesis, it does not take into account the fact that Part C began with a new sample of benzyl. If the product from part B had continued to be used, the yield would have been much lower. The product may have been lost due to residues left in various glassware used due to inefficient transfer or incomplete reactions. The aim of this experiment was to produce benzyl acid, not to have high yields so in that sense it was successful (excluding the formation of benzyl).