Ethanol and Glacial Acetic Acid Essay

Submitted By TheJosephBoi
Words: 548
Pages: 3
Open Document
Halogenation of Alkenes:
Bromination of trans-Cinnamic Acid

[pic] Two chiral centers So: Four stereoisomers are possible (2n = 22 = 4) But: Only TWO are formed !

[pic]

Theory: • Bromination of alkenes is stereospecific o Products contain 2 new chiral centers ▪ Products obtained from cis- alkenes are different from those obtained from trans-alkenes o Rationale: ▪ Formation of bromonium ion intermediate • NOT a “free” carbocation o A carbocation intermediate would lead to the formation of all possible stereoisomers. • Blocks one side of the molecule • SN2 attack by Br− from the opposite side leads to anti- addition overall ▪ Syn products are typically not formed (some exceptions do exist)
Mechanism:
[pic]

Experiment: Reaction: • Weigh 0.15g of trans- cinnamic acid into a reaction tube • Add 0.8 mL glacial acetic acid • Attach an air condenser and heat in a hot water bath (50oC), stirring occasionally, until the cinnamic acid dissolves. • Measure 1.0 mL of a 1.0 M solution of Br2 in acetic acid into a vial. • Use a Pasteur pipet to add this solution (to the cinnamic acid solution) through the top of the condenser. • Heat the reaction mixture in a hot water bath (50oC) until the red-brown color fades to light orange • Continue to heat for 15 min. • During this time: Plan Ahead! o Set up the filtration apparatus o Prepare an ice-water bath o Place a reaction tube containing deionized water in the ice-water bath to chill ▪ you will need it during filtration for washing/rinsing • If the mixture becomes colorless (or nearly so) during this period, add more Br2/acetic acid solution, dropwise, until the color just persists. • If the mixture has a distinct orange color at the end of the reaction period, add a drop or two of cyclohexene: it will turn light yellow.

Isolation: • Cool the reaction mixture in an ice-water bath for at least 10 minutes, scratching the sides of the tube to induce crystallization, if necessary. • Collect the product by vacuum filtration. • Wash with several portions of ice-cold water, until the acetic acid
Show More

Related Documents: Ethanol and Glacial Acetic Acid Essay

Trans-Cinnamic Acid Mechanism

In this experiment, the addition of bromine to trans-cinnamic acid was carried out to identify the product and mechanism from its melting point. The possible products were erythro-dibromide, threo-dibromide, or a mixture of both. The formation of the product was due to syn-addition, anti-addition, or both. Syn-addition was the addition of two substituents to the same side while anti-addition was the addition of two substituents to opposite sides of a double bond. Syn-addition yielded erythro-dibromide…

Words 1045 - Pages 5

Essay about Photochemical Synthesis of Benzopinacol and Its Acid-Catalyzed Rerrangement Product Benzopinacolone

its Acid-Catalyzed Rerrangement Product Benzopinacolone M.E.G. Balita Institute of Chemistry, University of Philippines, Diliman, Quezon City Date Performed: February 18, 2011 Date Submitted: March 4, 2011 Abstract In this experiment it is aimed to synthesize benzopinacol through photochemical reaction of benzophenone and, benzopinacolone via acid-catalyzed rearrangement of benzopinacol. In this experiment, mixture of benzophenone, isopropyl alcohol and a drop of glacial acetic acid…

Words 2797 - Pages 12

Preparation of 4-Bromoaniline Essay

electron pair on the nitrogen atom is delocalised by both the carbonyl group and the phenyl ring. The N-phenylethanamide was obtained in the form of crystals with a melting point of 78˚C. After this product was purified by recrystallisation from aqueous ethanol it was found to have a melting point of 106˚C which is much closer to the literature range of 113-114˚C. The percentage yield for the N-phenylethanamide was reasonably high at 82%. The second step in the formation of 4-bromoaniline, involved reacting…

Words 1841 - Pages 8

Fundulus Heteroclitus Lab Report

collected from the Winyah Bay Estuarine system in Georgetown, South Carolina. The DNA was isolated using the DNeasy Blood and Tissue Kit (Qiagen). The fin clips were digested with buffer ATL and Proteinase K by incubating at 56ºC for 2 hrs. The DNA was ethanol precipitated with buffer AL. The DNA was centrifuged at 8,000 rpm for 1 minute and washed with buffer AW1. The centrifugation was repeated. The samples were washed with buffer AW2 and centrifuged for 14,000 rpm for 3 minutes. The DNA was eluted from…

Words 1792 - Pages 8

Essay about Collagen Content

Background In the period between 1920-1935 Nageotte (1927a, b, 1928, 1930, 1933), Nageotte & Guyon (1933), Leplat (1933), and Faure-Fremiet (1933) had studied and observed the partial dissolution of collagen in dilute solutions of weak acids such as formic and acetic acid. Renewed interest in this soluble protein was generated in the period between 1940-1955 with the works of Orekhovich and his colleagues in the U.S.S.R., who reported the extraction of a soluble collagenous-type protein from the skin…

Words 5693 - Pages 23

Essay Review Chemistry Chapter 4

following compounds is a strong electrolyte? E A. H2O B. O2 C. H2SO4 D. C6H12O6 (glucose) E. CH3COOH (acetic acid) Answer: C 4.2 Which of the following compounds is a strong electrolyte? E A. H2O B. N2 C. KOH D. C2H6O (ethanol) E. CH3COOH (acetic acid) Answer: C 4.3 Which of the following compounds is a weak electrolyte? E A. HCl B. CH3COOH (acetic acid) C. C6H12O6 (glucose) D. O2 E. NaCl Answer: B 4.4 Which of the following compounds…

Words 4654 - Pages 19

Essay on Immunofluorescence Report

(a.k.a. TBS) after the plates were exposed to different solutions and antibodies in subsequent steps of the experiment. The medium that was originally on the plate was removed, and then the plate was washed with 2 mL of TBS. Subsequently, 5% glacial acetic acid in…

Words 1154 - Pages 5

Bb552 Study Guide Essay

a 1% w/v solution kept at 60˚C. A lower concentration of agarose is used for separating larger DNA fragments and higher concentrations for separating smaller DNA fragments. We use 1X TAE buffer when we run our gels: 1. Tris base 2. glacial acetic acid 3. EDTA, pH 8.0 We use blue juice as our sample buffer, it has two main components: 1. Sucrose – to weigh down the sample so it will not float out of the well 2. Bromophenol Blue – a tracking dye for migration of the sample through…

Words 2776 - Pages 12

Essay Purpose In This Experiment TLC Will

plates. We did this three times for each one and then we waited for it to dry. After the reference plate has been spotted, we got a screw cap jar to use as our development chamber. In the chamber we poured the development solvent, which was 0.5% glacial acetic acid in ethyl acetate. We put the plates in there gently allowing the solvent to reach about 0.5 cm. to the top. This process took about 10 minutes. After it was done we waited till the plates dried, and then took the plates under the UV Visualization…

Words 1423 - Pages 6