INTRODUCTION The purpose of this experiment involved synthesis of diphenylmethanol using phenylmagenisum bromide and benzaldehyde, using the method called Grignard reaction. Grignard reactions are an important method for new carbon-carbon bond formation as well as for the synthesis of alcohols. In Grignard reaction, when an alkyl or aryl halide, R-X where “X” is a halogen atom (i.e. Cl, Br, I) is reacted with organometallic compound such as magnesium, Mg. It forms a product RMgX which is known as Grignard reagent. The Grignard reagent formation always undergoes through dry anhydrous ether solvent due to its ability to act as Lewis base (donates pair of electrons) which is necessary to solvate and stabilize the RMgX Grignard reagent. In this experiment, the aryl halide bromobenzene was reacted with magnesium turnings in anhydrous diethyl ether solvent to form the Grignard reagent, phenylmagenisum bromide. It is very important and necessary that all reagent, solvent and glassware that were used were dry because even a small amount of water can react violently and form a hydrocarbon and wipe out the Grignard reagent. Once the reagent is formed it is further synthesized and then reacted with aldehyde or ketone to form a secondary or tertiary alcohol respectively, through its carbonyl group. For this …show more content…
benzaldehyde to synthesize after protonation into diphenylmethanol which is a secondary alcohol. This reaction takes place due to the nucleophilic carbonyl group
Wittig reactions allow the generation of an alkene from the reaction between an aldehyde/ketone and an alkyl halide (derived from phosphonium salt).The mechanism for the synthesis of trans-9-(2-phenylethenyl) anthracene first requires the formation of the phosphonium salt by the addition of triphenylphosphine and alkyl halide. The phosphonium halide is produced through the nucleophilic substitution of 1° and 2° alkyl halides and triphenylphosphine (the nucleophile and weak base). An example is benzyltriphenylphosphonium chloride, which was used in this experiment. The second step in the formation of the of the Wittig reagent, which is primarily called a ylide and derived from a phosphonium halide. In the formation of the ylide, the phosphonium ion in benzyltriphenylphosphonium chloride is deprotonated by the base, sodium hydroxide to produce the ylide as shown in equation 1.
In a separate beaker, acetone (0.587 mL, 8 mmol) and benzaldehyde (1.63 mL, 16 mmol) were charged with a stir bar and stirred on a magnetic stirrer. The beaker mixture was slowly added to the Erlenmeyer flask and stirred at room temperature for 30 minutes. Every 10 minutes, a small amount of the reaction mixture was spotted on a TLC plate, with an eluent mixture of ethyl acetate (2 mL) and hexanes (8 mL), to monitor the decrease in benzaldehyde via a UV light. When the reaction was complete, it was chilled in an ice bath until the product precipitated, which was then vacuum filtrated. The filter cake was washed with ice-cold 95% ethanol (2 x 10 mL) and 4% acetic acid in 95% ethanol (10 mL). The solid was fluffed and vacuum filtrated for about 15 minutes. The 0.688 g (2.9 mmol, 36.8%, 111.3-112.8 °C) product was analyzed via FTIR and 1H NMR spectroscopies, and the melting point was obtained via
Triphenylmethyl Bromide. A 400 mL beaker was filled with hot water from the tap. Acetic acid (4 mL) and solid triphenylmethanol (0.199 g, 0.764 mmol) were added to a reaction tube, with 33% hydrobromic acid solution (0.6 mL) being added dropwise via syringe. The compound in the tube then took on a light yellow color. The tube was then placed in the beaker and heated for 5 minutes. After the allotted time, the tube was removed from the hot water bath and allowed to cool to room temperature. In the meantime, an ice bath was made utilizing the 600 mL plastic beaker, which the tube was then placed in for 10 minutes. The compound was then vacuum filtered with the crystals rinsed with water and a small amount of hexane. The crude product was then weighed and recrystallized with hexane to form fine white crystals, which was triphenylmethyl bromide (0.105 g, 0.325 mmol, 42.5%). A Beilstein test was conducted, and the crystals produced a green to greenish-blue flame.
Abstract: Various Anilines were tested with Br2/HBr solution, the products were crystallized and melting points attained to verify relative reactivity. My assignment, 2,4-Dibromoanisol, was prepared in a yield of 52% with a melting point of 55-58 C .
The purpose of this experiment was to investigate the bromination of trans-cinnamic acid and determine what the isolated products tells us about the possible mechanism. The stereochemistry of the product results from either a syn or anti addition of Br2 to the alkene. Recrystallization using ethanol and water solvent mixture was used to purify the crude product and melting point was implemented in order to see which products were synthesized. The syn addition products (2S, 3S- and 2R, 3R) 2,3-dibromo-3-phenylpropanoic acid have a melting range of 93.5-95 ᵒC. The anti addition products (2S, 3R- and 2R, 3S) 2,3-dibromo-3-phenylpropanoic acid have a melting range of 202-204 ᵒC.
In this experiment a Grignard reaction was carried out to give the desired reagents: benzyl magnesium chloride. This was achieved by reacting benzyl chloride with magnesium in ether. After the Grignard’s reagents were formed, it was reacted with benzaldehyde in ether to give 1,2-diphenylethanol. The main objective of this experiment was to synthesize 1,2-diphenylethanol via a Grignard reaction. The NMR proves that the right product was formed in this experiment.
In this two week project, an experiment was designed and tested. The experiment was performed to tested how a variable affects the E/Z ratio products of a Wittig reaction.
Discussion The reaction of (-)-α-phellandrene, 1, and maleic anhydride, 2, gave a Diels-Alder adduct, 4,7-ethanoisobenzofuran-1,3-dione, 3a,4,7,7a-tetrahydro-5-methyl-8-(1-methylethyl), 3, this reaction gave white crystals in a yield of 2.64 g (37.56%). Both hydrogen and carbon NMR as well as NOESY, COSY and HSQC spectrum were used to prove that 3 had formed. These spectroscopic techniques also aided in the identification of whether the process was attack via the top of bottom face, as well as if this reaction was via the endo or exo process. These possible attacks give rise to four possible products, however, in reality due to steric interactions and electronics only one product is formed.
The purpose of conducting this experiment was to synthesise and characterise for the preparation of benzocaine via a fishcer esterification reaction by the means of amino benzoic acid alongside ethanol. The product was also precipitated from a solution in order to gain a pH of 8.The secondary aim was to esterify the reaction in an equilibrium reaction catalysed via the addition of acid shown below:
The goal of this experiment is to determine which products are formed from elimination reactions that occur in the dehydration of an alcohol under acidic and basic conditions. The process utilized is the acid-catalyzed dehydration of a secondary and primary alcohol, 1-butanol and 2-butanol, and the base-induced dehydrobromination of a secondary and primary bromide, 1-bromobutane and 2-bromobutane. The different products formed form each of these reactions will be analyzed using gas chromatography, which helps understand stereochemistry and regioselectivity of each product formed.
As a final point, the unknown secondary alcohol α-methyl-2-naphthalenemethanol had the R-configuration since it reacted the fastest with S-HBTM and much slower with R-HBTM. TLC was a qualitative method and ImageJ served as a quantitative method for determining which reaction was the faster esterification. Finally, 1H NMR assisted in identifying the unknown from a finite list of possible alcohols by labeling the hydrogens to the corresponding peaks.
Then the reaction tube was capped but not tightly. The tube then was placed in a sand bath reflux to heat it until a brown color was formed. Then the tube was taken out of the sand bath and allowed to cool to room temperature. Then the tube was shaken until a formation of a white solid at the bottom of the tube. After formation of the white solid, diphenyl ether (2 mL) was added to the solution and heated until the white solid was completely dissolved in the solution. After heating, the tube was cooled to room temperature. Then toluene (2 mL) was added to the solution. The tube was then placed in an ice bath. Then the solution was filtered via vacuum filtration, and there was a formation of a white solid. Then the product was dried and weighed. The Final product was hexaphenylbenzene (0.094 g, 0.176 mmol,
Chemical kinetics is a branch of chemistry that involves reaction rates and the steps that follow in. It tells you how fast a reaction can happen and the steps it takes to make complete the reaction (2). An application of chemical kinetics in everyday life is the mechanics of popcorn. The rate it pops depends on how much water is in a kernel. The more water it has the quicker the steam heats up and causes a reaction- the popping of the kernel (3). Catalysts, temperature, and concentration can cause variations in kinetics (4).
In this lab, it was determined how the rate of an enzyme-catalyzed reaction is affected by physical factors such as enzyme concentration, temperature, and substrate concentration affect. The question of what factors influence enzyme activity can be answered by the results of peroxidase activity and its relation to temperature and whether or not hydroxylamine causes a reaction change with enzyme activity. An enzyme is a protein produced by a living organism that serves as a biological catalyst. A catalyst is a substance that speeds up the rate of a chemical reaction and does so by lowering the activation energy of a reaction. With that energy reactants are brought together so that products can be formed.
Gas chromatography is a technique by which mixtures of volatile substances can be separated. Mass spectroscopy is a technique that analyses the mass of volatile molecules and their fragments. By using both techniques together, separated compounds are detected by their mass fragments. In this experiment, the CSUDH Chemistry Department Agilent 6890 N Gas Chromatograph, interfaced with an Agilent 5975B XL Mass Selective Detector was used. With this GC-MS machine, a mixture of compounds can be separated and detected by analyzing the mass spectrum data.