Observations
In step one, a 0.1 grams of 4-t-butylcyclohexanone and 0.2 mL of methanol was placed into a long-neck round-bottom flask. The contents were swirled and a boiling chip was placed. 0.023 grams of NaBH4 was weighed to prepare the sodium borohydride solution. Once ready, 0.6 mL of the sodium borohydride solution was added to the apparatus. The reaction was allowed to proceed for about ten minutes. During this time, 0.5 mL of 1 N HCL was chilled in a small dram vial. Once the reaction was complete, using a pipette the cold hydrochloric acid was added to the flask. In step nine, the solution was extracted three times using 0.5 mL increments of methylene chloride. To do this the contents from the flask were washed with one 0.5 mL increment
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of the methylene chloride then pipetted to a reaction tube.
After corking and inverting the reaction tube, the organic layer was removed and transferred to another reaction tube. Then another increment of 0.5 mL of methylene chloride was added to the first reaction tube and the extraction process was repeated. This was done a total of three times. Then in step thirteen, about five scoops of anhydrous sodium sulfate was added to the second reaction tube. Then a filter pipette was prepared and the organic solution from the second reaction tube was added to the pipette.The mixture was allowed to gravity filter and an additional 0.5 mL increment of methylene chloride was added into the pipette and the process was repeated again. Then in step 18, the collected solutions poured onto a watch glass. It was observed that the pre-weighed watch glass weighed 26.196 grams. The watch glass was placed over the beaker that was filled with 30mL of water. It was observed that it took about fifteen minutes for the solvent …show more content…
to evaporate. After letting the watch glass cool for a while, it was observed that the weight of the watch glass with the solvent was 26.207 grams. The melting point was determined to be 64 degrees Celsius. Calculations -Reactant: 4-t-butylcyclohexanone: Amount: 0.1 grams Molecular weight: 154.253 g/mol (0.1g)/(154.253g/mol)= 6.48x10-4 mol NaBH4: Amount: 0.023 grams Molecular Weight: 37.83 g/mol 1M(0.6mL)=(0.023g)/(37.83g/mol)=6.08x10-4 mol -Product: 4-t-butylcyclohexanol: Amount collected: 0.011 grams Molecular weight: 156.269 g/mol -Theoretical: (6.08x10-4 mol)x(156.269g/mol)=0.0950g -Percent Yield (0.011g/0.0950g)x100%= 11.58% Conclusions The purpose of this experiment was to reduce a ketone by using NaBH4.
A reaction involving a decrease in oxidation state is called a reduction. An advantage of using NaBH4 is that it does not react rapidly with alcohols.1 NaBH4 may be performed using ethanol, water, methanol, or isopropanol solvent. Sodium borohydride is is much less reactive as a base or nucleophile than lithium aluminum hydride. Therefore the reaction would be able to run in methanol without concern for traces of water. 2 When using NaBH4, ketones are reduced to secondary alcohols. There are two steps that take place when doing this mechanism, the first is a nucleophilic attack of a hydride ion on the electrophilic carbonyl carbon and then a protonation of the resulting alkoxide by either water or some other acid.
3 The melting point of 4-t-butylcyclohexanol recorded was 64 degrees Celsius. This fit into the melting point range that is 62 to 70 degrees Celsius. This experiment resulted in a low percent yield of 11.58%. There could be many explanations to account for the low percent yield. One could be that some impurities were extracted when extracting the organic layer. This could have caused the solvent not to evaporate correctly. The solids were not completely dry and this could have affected the weight recorded, to avoid this for future experiments there should be extra caution when extracting the organic layer.
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%).
The actual amount of crude product was determined to be 3.11 grams. The percent yield of the crude product was determined to be 67.75 %. The actual amount of pure product formed was found to be 4.38 grams. The percent yield of the pure product was determined to be 95.42%. Regarding the thin layer chromatography, the line from the solvent front is 8 centimeters.
For this experiment we have to use physical methods to separate the reaction mixture from the liquid. The physical methods that were used are filtration and evaporation. Filtration is the separation of a solid from a liquid by passing the liquid through a porous material, such as filter paper. Evaporation is when you place the residue and the damp filter paper into a drying oven to draw moisture from it by heating it and leaving only the dry solid portion behind (Lab Guide pg. 33.).
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.
In this lab 4-tert-butylcyclohexanone is reduced by sodium borohydride (NaBH4) to produce the cis and trans isomers of 4-tert-butylcyclohexanol. Since the starting material is a ketone, NaBH4 is strong enough to perform a reduction and lithium aluminum hydride is not needed. NaBH4 can attack the carbonyl group at an equatorial (cis) or axial (trans) position, making this reaction stereoselective. After the ketone is reduced by the metal-hydride, hydrochloric acid adds a proton to the negatively charged oxygen to make a hydroxyl group. The trans isomer is more abundant than the cis based on the results found in the experiment and the fact that the trans isomer is more stable; due to having the largest functional groups in equatorial positions.
Each subsequent trial will use one gram more. 2.Put baking soda into reaction vessel. 3.Measure 40 mL vinegar. 4.Completely fill 1000 mL graduated cylinder with water.
Once the mixture had been completely dissolved, the solution was transferred to a separatory funnel. The solution was then extracted twice using 5.0 mL of 1 M
barbier reaction: In a 50 mL round bottom flask that had a reflux condenser attachment, saturated ammonium chloride (5 mL), THF (1 mL), zinc powder (0.4 g), benzaldehyde (0.500 mL, 0.5225 g, 4.92 mmol), and allyl bromide (0.470 mL, 0.6533 g, 5.40 mmol) were charged with stir bar and stirred at room temperature for 45 minutes. Diethyl ether (10 mL) was added to the reaction mixture and stirred. The mixture was gravity filtered into a beaker that was topped with a watchglass. The filtrate was transferred to a separatory funnel and the organic layer was extracted with deionized water (10 mL) and diethyl ether (15 mL). The organic layer was placed into an Erlenmeyer flask and the aqueous layer was placed into a beaker, which was extracted with
Benzyl bromide, an unknown nucleophile and sodium hydroxide was synthesized to form a benzyl ether product. This product was purified and analyzed to find the unknown in the compound. A condenser and heat reflux was used to prevent reagents from escaping. Then the solid product was vacuum filtered.
Camphor is a trepenoid compound, meaning that it is derived from five-carbon isoprenes. Common uses of Camphor include insect repellent, fireworks and culinary purposes. In acetic acid, a secondary alcohol is converted to camphor following an oxidation reduction reaction. Sodium Borohydride is then used to give an isomeric alcohol, meaning that it has the same chemical formula as another molecule but has a different chemical structure. Since ketones can be easily reduced by metal hydrides such as LiALH4 and NaBH4, they are often used in reducing carbonyl groups. For this experiment sodium bromide is used as the reducing agent, which will reduce camphor to produce two products, namely borneol and isoborneol. For the reaction to
The objective of this experiment was to perform extraction. This is a separation and purification technique, based on different solubility of compounds in immiscible solvent mixtures. Extraction is conducted by shaking the solution with the solvent, until two layers are formed. One layer can then be separated from the other. If the separation does not happen in one try, multiple attempts may be needed.
Materials and Methods: An ion exchange chromatography column was obtained and set up for purification with the addition of 0.5 ml ion exchange matrix. 1 ml
of distilled water. For the 1M solution I added 50 cm3 of HCl and 50
Before any chemical reactions occurred, there was 0.46 grams of elemental copper metal. After the copper was added to the 250 milliliter beaker containing the 5.0 milliliters of nitric acid, nitrogen dioxide gas came out. The gas color was a light brown color, and the clear nitric acid within the beaker became a green-brown color. Once the chemical reaction concluded and nitrogen dioxide gas stopped releasing from the beaker, 20 milliliters of distilled water was added to the solution, and the color within the beaker turned to a neon blue. This was the chemical equation for the first chemical reaction, 4 HNO3 (aq) + Cu (s) → Cu(NO3)2 (aq) + H2O (l) + 2 NO2 (g).
In this experiment three different equations were used and they are the Stoichiometry of Titration Reaction, Converting mL to L, and Calculating the Molarity of NaOH and HCl (Lab Guide pg. 142 and 143).