Cydohexyl bromide

EPM/EPDMcompounding [ELASTOTffiRS, SYNTHETIC - ETHYLENE-PROPYLENE-DIENE RUBBER] (Vol 8) Cydohexyl bromide [108-85-0]... 

Cydohexyl bromide Potassium ethoxide Cyclohexane Ethanol... 

Isopropylation and cyclohexylation reactions of naphthalene with isopropyl bromide and cydohexyl bromide respectively were first studied over a series of mordenites and Y zeolites at 200°C in cyclohexane as the solvent. 

Attach a copy of your chromatogram to your Data Analysis Sheet. Label the cydohexene and cydohexyl bromide peaks. Show the area measurements on the chromatogram and aU the calculations in your report. What condusions can you draw based on your results Indude an explanation of the condusions drawn. 

Replacing cydohexyl bromide with cydohexyl chloride. 

Determine the percentage of unreacted cydohexyl bromide in the sample mixture from the chromatogram for parameters 1,2, and 3. Determine the percentage of cydohexyl chloride and iodide in parameters 4 and 5, respectively. 

In this set of experiments track only the disappearance of cydohexyl bromide, and not the appearance of cyclohexene. As mentioned previously, the amount of cyclohexene observed in successive aliquots tends to drop below the predicted values because of the sampling techniques employed. As the reaction progresses, however, the amount of cydohexyl bromide continues to decrease at the predicted rate (see below). 

Use of an Internal Standard. How can we quantitatively track the disappearance of cydohexyl bromide As we have seen, the ratio of cydohexyl bromide to cyclohexene cannot be determined accurately because of the inaccuracies in measuring the cyclohexene formed in the reaction. Also, there are small inaccuracies in the amount of the reaction mixture removed from the system for any given sample. These problems are solved by standardizing the samples. An internal standard is added to the reaction mixture. Ideally, this standard should not interfere with the reaction being studied and the substance must be easy to track by GC. In these experiments we wiU use toluene. 

Toluene is not very volatile (bp 110.6 °C) and has a retention time on the GC that does not interfere with the resolution of any other peaks on the chromatogram. It will be added in a known amount to the reaction mixture before you begin. For each gas chromafogram we can then measure the area of the standard s peak and use it to determine the amount of cydohexyl bromide in the reaction mixture at that point. 

The Calculations Using an Internal Standard. The calculations allow us to compare the amount (%) of cydohexyl bromide (or chloride or iodide) reacted at the 30-min time point for each of the different reaction parameters. 

Cyclohexene, bromination of, 47, 32 reaction with 1-butyl perbenzoate and cuprous bromide, 48,18 2-Cyclohexenol, 46, 32 2-Cyclohexen-I-ol, benzoate, 48, 18 2-Cyclohexenone, 45, 32 Cydohexyl allophanamide, 45, 72 Cyclohexylamine, 45, 85 reaction with 1-butyl hypochlorite, 46, 16... 

The effect of the leaving group was briefly examined but cinnamyl bromide gave a substantially lower ee (38%). Cinnamyl dimethyl phosphonate or acetate gave very poor results. The cydohexyl-substituted allylic acetate 21 on the other hand afforded a completdy y-selective reaction but the product turned out to be racemic. Changing the Grignard reagent halide from bromide to either chloride or iodide resulted in very low ees. 

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