Oxidation of a Secondary Alcohol with Chromic Acid in Diethyl Ether to Produce a Ketone Compound Amber Breakspear 15202075 – 12th January 2016 Year 1 Full Report 1 – Organic Abstract An effective oxidation of the secondary alcohol with chromic acid to produce the corresponding ketone. In this report the synthesis of 4-methyl-2-pentanone from 4-methyl-2-pentanol via an adapted jones oxidation1, using diethyl ether as the solvent and concentrated sulphuric acid, is described. An overall yield of 35.74 % was achieved and the product was characterised by NMR, IR and boiling point analysis. Introduction The conversion of an alcohol into a carbonyl compound is of great importance to the chemistry discipline. Oxidation of alcohols …show more content…
This takes place by addition of the alcohol oxygen to chromium, forming a zwitterion. Water removes a proton which is transferred to the chromate ester. After hydrolysis, the carbonyl compound is formed (fig.5). By limiting the amount of water and oxidant present in the reaction , the second oxidation can be stopped and an aldehyde forms (see fig 1 where R1 = H).3 Tertiary alcohols are resistant to oxidation because you need at least one alpha hydrogen attached to the carbinol …show more content…
Cr(VI) oxidants are able to oxidise any CH bonds on a carbinol carbon as far as possible and no carbon-carbon bonds are broken so allows for selective oxidation. They have strong oxidising power and consequently will oxidise both secondary alcohols to ketones and primary alcohols to carboxylic acids. An example of this is Jones reagent (see fig.2) which was discovered in and is typically a solution of chromium trioxide in dilute sulphuric acid and acetone. In some cases only the aldehyde is required so Cr(VI) oxidants are not required; therefore a weak oxidising agent, with milder conditions is useful such as pyridinium dichromate. 1’ Figure 2-Typical Jones oxidation of 1⁰ and 2⁰ alcohols With uses of carbonyls ranging from flavouring agents to acting as intermediates to make pharmaceuticals, results and further research could have a potential impact on both the chemical industry and the public. In particular, the product formed in the experiment, 4-methy-2-pentone, is used for organic solvents and as a material used in the preparation of many chemical compounds and paints. 5 Materials and Experimental
The goal of this two week lab was to examine the stereochemistry of the oxidation-reduction interconversion of 4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone. The purpose of first week was to explore the oxidation of an alcohol to a ketone and see how the reduction of the ketone will affect the stereoselectivity. The purpose of first week is to oxidize the alcohol, 4-tert-butylcyclohexanol, to ketone just so that it can be reduced back into the alcohol to see how OH will react. The purpose of second week was to reduce 4-tert-butylcyclohexanol from first week and determine the effect of the product's diastereoselectivity by performing reduction procedures using sodium borohydride The chemicals for this lab are sodium hypochlorite, 4-tert-butylcyclohexanone
Wittig reactions allow the generation of an alkene from the reaction between an aldehyde/ketone and a ylide (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) 4 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. The positive charge on the phosphorus atom is a strong EWG (electron-withdrawing group), which will trigger the adjacent carbon as a weak acid 5 Very strong bases are required for deprotonation such as an alkyl lithium however in this experiment 50% sodium hydroxide was used as reiterated. Lastly, the reaction between ylide and aldehyde/ketone produces an alkene.3
The article, “Asymmetric one-pot Robinson annulations” (Rajagopal et al., 2001) describes the procedure of a Robinson Annulation Reaction that converts a five-membered cyclic ketone to a two-ring, bicyclic compound. In this reaction, 1.12 g of 0.01 mol dione was added to a solution of 1.15 g of 0.01 mol S-proline in dry DMSO and mixed in a beaker, followed by 0.7 g of 0.01 mol methyl vinyl ketone. This mixture was stirred for 145 ...
The three butene products have been verified to elute in the following order: 1-butene, trans-2-butene, and cis-2-butene. Theory: The dehydration of 2-butanol, a secondary alcohol, progresses readily in the presence of a strong acid like concentrated sulfuric acid (H2SO4). The reaction is completed via the E1 mechanism. Initially, the hydroxyl group is a poor leaving group, but that is remedied by its protonation by the acid catalyst (H2SO4) converting it to a better leaving group, H2O. The loss of this water molecule results in a secondary carbocation intermediate that continues to form an alkene in an E1 elimination.
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.
The purpose of this experiment is to determine the absolute configuration of an unknown chiral secondary alcohol using the competing enantioselective conversion (CEC) method. This method uses both R- and S- enantiomers of a chiral acyl-transfer catalyst called homobenzotetramisole (HBTM), in separate parallel reactions, and thin layer chromatography to identify the stereochemistry of the secondary alcohol, whether it be an R- or S- enantiomer. Quantitative analysis was performed using a program called ImageJ after the appropriate picture was taken of the stained TLC plate. The molecular structure of the unknown alcohol was identified using 1H NMR spectroscopy by matching the hydrogens to the corresponding peak.
In a small reaction tube, the tetraphenylcyclopentadienone (0.110 g, 0.28 mmol) was added into the dimethyl acetylene dicarboxylate (0.1 mL) and nitrobenzene (1 mL) along with a boiling stick. The color of the mixed solution was purple. The solution was then heated to reflux until it turned into a tan color. After the color change has occurred, ethanol (3 mL) was stirred into the small reaction tube. After that, the small reaction tube was placed in an ice bath until the solid was formed at the bottom of the tube. Then, the solution with the precipitate was filtered through vacuum filtration and washed with ethanol. The precipitate then was dried and weighed. The final product was dimethyl tertraphenylpthalate (0.086 g, 0.172mmol, 61.42%).
Alkylated phenols and their derivatives are important materials in both organic synthesis and chemical manufacturing. Mono-alkylphenols and di-alkylphenols are used as raw materials for the manufacture of a wide variety of products such as resins, wire enamels, varnishes, printing inks, antioxidants, flame retardants, ultraviolet absorbers, fungicide, petroleum additives and rubber chemicals [1-17]. Friedel–Crafts alkylation of phenol with tert-butyl alcohol (TBA) produces 2-tert-butylphenol (2-TBP), 4-tert-butylphenol (4-TBP), 2,4-di-tert-butylphenol (2,4-DTBP), 2,6-di-tert-butylphenol (2,6-DTBP) and tert-butylphenol ether (TBPE), depending on both the catalyst and the reaction conditions. Based on previous researches, it is well known that moderate acid catalysts or high reaction temperature led to carbon alkylated products and TBPE is produced in the presence of weak acidic catalysts as a major product. 2-TBP is the jarless product of alkylation of phenol with TBA owing to the presence of phenolic (–OH) group on the aromatic ring that kinetically favours o-alkylation. However, due to steric hindrance, thermodynamically unfavoured o-isomer (2-TBP) is readily isomerized into less hindered p-isomer (4-TBP), especially in moderate acidic media. If strong acid catalysts are used in the alkylation reaction, 2,4-DTBP is a dominant product [17,18]. 2,4-DTBP is used in the manufacture of its triphosphite and benzotriazole, which are employed as a co-stabilizer for PVC or UV absorbers in polyolefins [12,13]. 2-TBP is an intermediate for pesticides, fragrances and antioxidants [14]. High selectivity toward 4-TBP is favored since this product imparts enhanced properties to the class of metallic detergents (phenates) used in lubricating oil...
Ethanol is the only alcohol that can be drunk safely and is found in all alcoholic drinks. Throughout this investigation I am going to investigate to different factors that affect the breakdown of an alcohol. [IMAGE]e.g. Methane (HCO) + Oxygen (O2) Carbon dioxide (CO2) + Water (H2O) Aim --- I am going to investigate increasing the chain length and see what effect there is on the heat of combustion.
Predictions may be made about the suitability of possible catalysts by assuming that the mechanism of catalysis consists of two stages, either of which can be first:
Alcohol chemically is any organic molecule with an OH functional group, however for the sake of this essay the term alcohol will refer to ethanol, the type of alcohol used in regular consumption. Ethanol is a by-product of yeast (a type of micro-organism). Yeast consume glucose, sugars, from fruits or crops such as barley they then excrete carbon dioxide (CO2) and ethanol (C2H5OH or C2H6O) (How is alcohol made?, n.d.). Yeast do this by the presence of the enzyme zymase in their digestive system. The enzyme speeds up the otherwise long process of glucose break down into carbon dioxide and ethanol, fermentation. This can be represented by the chemical formula:
Preview Main Points: I am going to inform you on how alcohol is made and how it affects humans in different ways.
2, 4-dihydroxy benzaldehyde (2.83 g), Cl-SBA-15 (2 g) and triethylamine (2 g) in 50 mL of toluene was refluxed for 3 hours at 80-90 ºC in the water bath. Then, the solid was filtered, rinsed sequentially with ethanol and dried in a vacuum oven at 80 oC. Then, 1.96 mL of ethanolamine was added on the resulting substance in 50 mL of toluene and refluxed at 110ºC for 48 hours in oil bath under a nitrogen atmosphere. The product was centrifuged, washed with 50 mL of ethanol, diethyl ether, distilled water and dried in vacuum for 10 h at 90ºC. Finally, any residual template and organosilane was removed by Soxhlet extraction over diethylether and dichloromethane (1:1) at 100 ºC for 24 h and heated for 10 h at 40ºC under vacuum. Synthesis steps are presented in Scheme 1.
Alcohol is a class of organic compounds that is characterized by the presence of one or more hydroxyl groups (-OH) attached to a carbon atom. Alcohol was unknowingly produced centuries ago when fermentation occurred to crushed grapes (Pines, 1931). In today’s society alcohol is produced for the use of household products such as varnishes, cleaning products, but is more commercially important in the liquor business. A chemical process called fermentation accomplishes the production of ethanol, the alcohol or liquor. From there, the ethanol goes through distinct processes to become the dark and clear liquors on the store shelves.