Experiment 8.2: Nucleophilic Aliphatic Substitution: Synthesis of 1-Bromobutane
Reference:
Schoffstall, Allen M., Barbara A. Gaddis, and Melvin L. Druelinger. "Experiment 8.2." Microscale and Miniscale Organic Chemistry Laboratory Experiments. New York: McGraw-Hill Higher Education, 2004. 267-70. Print.
General Procedure:
This experiment was designed to convert 1-butanol to 1-bromobutane by reacting with sulfuric acid and sodium bromide. Protonation of 1-butanol by hydrogen bromide and bromide ions on the alcohol group gave 1-bromobutane. Reflux, purification, and filtering were used to separate out the 1-bromobutane for testing using an GC spectrum and refractive index.
Synthesis of 1-Bromobutane
The compound was synthesized according to Experiment 8.2 from the Microscale and Miniscale Organic Chemistry
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Laboratory Experiments, starting on page 267.This was facilitated by adding 1.75 grams (17.01 mmols) of sodium bromide and 1.25 mL of water and 1.25 mL of 1-butanol (13.66 mmols) to a 10 mL round bottom flask fitted with a spin bar.
This was allowed to mix for a few minutes; a little excess water was used to ensure that sodium bromide was fully dissolved. This mixture was placed in an ice bath while continuing to stir. 1.3 ml (24.39 mmols) of concentrated sulfuric acid was added dropwise. The flask was removed from the ice bath and heated to reflux for 1 hour while continuing to stir. The resulting top layer was transferred to a conical vial in which 1.5 mL (22.51 mmols) of 80 % sulfuric acid was added. 2.0 mL of water was added to allow a layer to form. The bottom layer was removed and transferred to another conical vial in which 2.0 mL of saturated sodium bicarbonate was added. The bottom, organic layer, was transferred to a conical vial. Calcium chloride, a drying agent, was used to collect the remaining aqueous layer that
could remain. A filter pipet was used to clean the final product and to retrieve the most 1-bromobutane that was remaining. The oily residue was translucent yellow in color. A gas chromatograph (GC) spectrum indicated a peak at 3.393 minutes with an area of 95.99 % and a sensitivity height of 7.54. The only other product that was present as well, was the acetone used to wash the GC needle. Thus the product recovered had an estimated purity of 99.71 %. The percent recovered was not obtainable, however, if there was enough for a 5 microliter sample for be run in the GC, this would suggest the minimum of .05 ml was recovered. This would have further suggested that the percent recovery would then be 3.39 %. Due to the relatively low amount of percent recovered, there was not enough product to have an accurate refractive index, however, the literature suggested a refractory index of 1.4398 at a 99 % purity.
When 1-bromobutane is reacted with potassium t-butoxide there is only one product formed, 1-butene. This is because the halide is on a primary carbon thus producing only one product.
The complete experimental procedure is available in the General Chemistry Laboratory Manual for CSU Bakersfield, CHEM 213, pages 20-22, 24-25. Experimental data are recorded on the attached data pages.
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 isomerization procedure was done in order to create dimethyl fumarate from dimethyl maleate. Dimethyl maleate and dimethyl fumarate are cis and trans isomers, respectively. This procedure was done via a free radical mechanism using bromine. The analysis of carvones reaction was done in order to identify the smell and optical rotation of the carvone samples that were provided. The odor was determined by smelling the compound and the optical rotation was determined using a polarimeter.
Saturated sodium chloride solution, also known as brine solution, is used to wash the distillate mixture. The distillate mixture is the phosphoric acid the co-distilled with the product. The brine solution also removes most of the water from the 4-methylcyclohexane layer. When six drops of 4-methylcyclohexene were added with two
The primary goal of this laboratory project was to identify an unknown compound and determine its chemical and physical properties. First the appearance, odor, solubility, and conductivity of the compound were observed and measured so that they could be compared to those of known compounds. Then the cation present in the compound was identified using the flame test. The identity of the anion present in the compound was deduced through a series of chemical tests (Cooper, 2009).
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.
This experiment was divided into two main steps. The first step was the addition of bromine to trans-stilbene. Trans-stilbene was weighted out 2.00g, 0.0111mol and mixed with 40ml of glacial acetic acid in 100ml Erlenmeyer flask on a hot bath. Pyridinium hydrobromide perbromide of 4.00g, 0.0125mol was added carefully into the flask.
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.
A condenser and heat reflux was used to prevent reagents from escaping. Then the solid product was vacuum filtered. The product was recrystallized to purify it and the unknown
A small piece of cotton is then put into the bottom of the column, along with a 0.5 cm thick layer of sand (put on top of the cotton). 20 mL of petroleum ether, and with a dry funnel on top of the column, 7 g of alumina (Aluminum Oxide) is put into the column. To ensure that no alumina adheres to the sides, a glass rod in a rubber stopper can be put to use through the gentle tapping of the column with it; in addition, additional petroleum ether can also be put to use by rinsing the inner walls of the column with it. To cover the alumina, another 0.5-1 cm layer of sand is put to use. For the solvent to drain into an Erlenmeyer flask, the stopcock is to be open until the solvent level exactly reaches the top of the alumina, where the stopcock is then immediately shut off in order to prevent air bubbles from developing in the solid support. To load the sample into the column bed, 0.5 mL of a pre-made solution, containing 200 mg of fluorine and 9-fluorenone, as well as 0.5 mL of petroleum ether is to be carefully put on top of the column bed with a Pasteur pipet. At this point, the stopcock is to be open again until the top of the liquid level is at the top of the alumina. Next, with 1 mL of petroleum ether, the addition and draining process is then done a total of three more times, where upon the third draining, 10 mL of petroleum ether is be put into to the top of the column bed and put to drain into a small beaker (label it “Fraction 1”). After every 2-3 mL, a watchglass is used to collect a drop of eluent to determine if all white solid has been eluted (there may be a need of 10-20 mL of petroleum ether). Once all eluted, another small beaker (label it “Fraction 2”) can replace the beaker for “Fraction 1.” In “Fraction 2,” 5 mL of petroleum ether is used to elute (stop when yellow band starts to elute), followed by a change of eluent to dichloromethane.
W. A. Konig, D. H. Hochmuth, D. Joulain, Library of MassFinder 2.1 University of Hamburg, Institute of Organic Chemistry, Hamburg 2001
Add 138 mg of salicylic acid, a drop of 85 % phosphoric acid, 0.3 mL of acetic anhydride and a boiling chip into a reaction tube.Mix them thoroughly, and place in a steam bath for approximately 5 minutes. After the reaction tube rested in the steam bath for 5 minutes, 0.2 mL of water was added to the tube. The tube was then placed in a test tube rack to cool down to room temperture. Once the substance reached room tempertaure it was placed inside of an icebath for 10 minutes to crystallize. The product then had to undergo the filteration process. The filtered product was
To this mixture,3-4drops of concentrated sulfuric acid is added and the mixture is swirled. This will speed up the reaction.
Plontke, R. (2003, March 13). Chemnitz UT. TU Chemnitz: - Technische Universität Chemnitz. Retrieved April 1, 2014, from http://www.tu-chemnitz.de/en/