Formal Report - Synthesis of an Alkyl Halide

Theory: One of the methods of preparing alkyl halides is via the nucleophilic substitution reactions of alcohols. Alcohols are inexpensive materials and easy to maintain. However, they are a poor leaving group the OH group is a problem in nucleophilic substitution, this problem is fixed by converting the alcohol into H2O.

During the halogenation reactions of 1-butanol, 2-butanol, and 2-methyl-2-propanol, there is a formation of water from the OH atom of the alcohol, and the H atom from the HCl solution. The OH bond of the alcohol is then substituted with the Cl atom. Therefore all of the degrees of alcohol undergo halogenation reactions, and form alkyl halides as products. This is because the functional group of alkyl halides is a carbon-halogen bond. A common halogen is chlorine, as used in this experiment.

After synthesizing tert-butyl chloride, the melting point on the compound was found to be 47˚C. According to literature, tert¬-butyl chloride has a melting point of 51˚C, apart from a little bit of deviation, this shows that the correct compound was created. The percent yield obtained for the synthesis of tert-butyl chloride was 47.42%. This could have been due to errors that occurred in the lab. When moving the solution from one test tube or graduated cylinder to another some of the solution may still be left in the tube which lowers the percent yield. Also when working with a simple distillation setup, the vial is not distilled to dryness therefore some of the solution is not collected. Some of the solution can also be trapped on the side

The synthesis of the alkyl halide n-Butyl Bromide from alcohol is the foundation for the experiment. During the isolation of the n-butyl bromide, the crude product is washed with sulfuric acid, water, and sodium bicarbonate to remove any remaining acid or n-butyl alcohol. The primary alkyl halide halide n-butyl bromide is prepared by allowing n-butyl alcohol to react with sodium bromide and sulfuric acid. The sodium bromide reacts with sulfuric acid to produce hydrobromic acid . Excess sulfuric acid acts to shift the equilibrium and speed up the reaction by producing a higher concentration of hydrobromic acid. The

13. The temperature of the water was measured prior to the tube being placed in it and the temperature of the Hydrochloric Acid was measured after it 's temperature had adjusted.

In radical halogenations lab 1-chlorobutane and 5% sodium hypochlorite solution was mixed in a vial and put through tests to give a product that can then be analyzed using gas chromatography. This experiment was performed to show how a radical hydrogenation reaction works with alkanes. Four isomers were attained and then relative reactivity rate was calculated. 1,1-dichlorobutane had 2.5% per Hydrogen; 1,2-dichlorobutane had 10%; 1,3-dichlorobutane had 23%; and 1,4-dichlorobutane had 9.34% per Hydrogen.

In the process, extraction and distillation techniques were used. The theoretical amount of t- pentyl chloride was 17.358g, while 15.78 g was the actual amount produced which gave a percent yield of 90.9%. An error occurred while performing the experiment, the filtered dried product in the distillation process was placed in the wrong flask. Due to this that part of the experiment had to be redone and the new filtered product had some aqueous solution in it, which caused the boiling point to be under the specified temperature. The boiling point then was at 50 ℃ compared with the expected range of 79- 84 ℃. The IR spectrum used above was from another group’s results. The experimental IR spectrum has more prominent peaks in the 3000 cm-1 range compared to the expected IR spectrum. Nonetheless, the experimental IR spectrum resembles the expected IR spectrum in the sense that the peaks are closely around the same wavenumber range. This is probably due to the product being distilled at the right boiling

Tube 4 now should only have crude solid in the tube and it is then weighed. The tube is placed into a 50℃ water bath and then approximately 0.5 -1 ml of methanol is added, as well as H2O until the solution gets cloudy, once the solution is dissolved it is cooled to room temperature and then iced. The crystals are then collected using a Hirsh funnel. Next a small amount (~ 0.1g) of the crystals are placed into a melting point tube and placed into the melting point machine to record the unknown neutral substances melting point.

Distillation. Transfer the clear liquid to a dry 25-mL round-bottom flask using a Pasteur pipet. Add a boiling stone and distill the crude t-pentyl chloride in a dry apparatus. Collect the pure t-pentyl chloride in a receiver cooled in ice. Collect the material that boils between 78°C and 84°C. Weigh the product and calculate the percentage yield.

A unimolecular nucleophilic substitution or SN1 is a two-step reaction that occurs with a first order reaction. The rate-limiting step, which is the first step, forms a carbocation. This would be the slowest step in the mechanism. The addition of the nucleophile speeds up the reaction and stabilizes the carbocation. This reaction is more favorable with tertiary and sometimes secondary alkyl halides under strong basic or acidic conditions with secondary or tertiary alcohols. In this experiment, the t-butyl halide underwent an SN1 reaction. Nucleophiles do not necessarily effect the reaction because the nucleophile is considered zero order, (which makes it a first order reaction.) The ion that should have the strongest effect in an SN1 reaction is the bromide ion. The bromide ion should be stronger because it has a lower electronegativity than chloride as well as a smaller radius.

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The purpose of this experiment is to examine the reactivities of various alkyl halides under both SN2 and SN1 reaction conditions. The alkyl halides will be examined based on the substrate types and solvent the reaction takes place in.

After putting the CH2Cl2 to a beaker containing the drying agent anhydrous sodium sulfate, a sticky white solid was recovered.

The purpose of this lab is to understand the process of eliminating an alkyl halide to form an alkene. The experiment is carried out by first converting the alcohol, 2-methy-2-butanol, into the alkyl halide of 2-chloro-2-methylbutane that will then be put through dehydrohalogenation that favors elimination reaction (E2) to create a mixture of 2-methyl-2-butene and 2-methyl-1-butene. A fractional distillation will be taken to purify the mixture and an additional gas chromatography will be done to further analyze the mixture composition. A bromide test will be done to determine the product of an alkene in the experiment.

This lab consisted of the conversion of alcohols into alkyl halides through common substitution methods. These methods include SN1 and SN2 mechanism, both of which can occur for this type of reaction. For both reactions, the first step of protonation will be to add hydrogen to the –OH group and then the rest of the reaction will proceed according to the type of mechanism. SN1 reactions form a cation intermediate once the H2O group leaves, then allowing a halide (such as Br) to attack the positively charged reagent1. On the other hand, SN2 reactions are one-step mechanism in which no intermediate is formed and the halide attaches as the leaving