Chemistry of Alkenes - Lab Report Example

Your Full The Chemistry of Alkenes The synthesis of an alkene from 3-chloro-3methylpentane was done for this experiment. Beilstein. bromine and potassium permanganate tests were done and the observations were noted. The distillate was also subjected to FTIR and GC analysis to confirm its identity.1. Report a percent yield and show your calculations. Given:Density of 3-chloro-3-methylpentane (g/mL)0.885Volume of 3-chloro-3-methylpentane used (mL)1.4Weight of empty flask (g)7.600Weight of flask + product (g)12.

020MW of 3-chloro-3-methylpentane (g/mol)120.62MW of 3-methyl-2-pentene (g/mol)84.16Chemical reaction: CH3C(C2H5)2Cl + KOH/Heat → C2H5C(CH3)=CHCH3 + KCl (a) Theoretical yieldMass = volume * Density = 1.4mL * (0.885g/mL) Mass = 1.239g # of moles of CH3C(C2H5)2Cl = 1.239g CH3C(C2H5)2Cl * 1 mol CH3C(C2H5)2Cl 120.62g# of moles of CH3C(C2H5)2Cl = 0.01027 mol Theoretical yield = 0.01027 mol CH3C(C2H5)2Cl * 1 mol 3-methly-2-pentene * 84.16g 3-methyl-2-pentene 1 mol CH3C(C2H5)2Cl 1 mol 3-methyl-2-penteneTheoretical yield = 0.

8643 g 2-pentene(b) Percent Yield % yield = (mass of actual yield/mass of theoretical yield) x 100 = (12.020g - 7.600g) / 0.8643 x 100 % yield = 511%2. Attach and interpret all data acquired during the experiment. Were the starting materials completely consumed? Explain.Test ConductedObservationBelstein Green flame appearedBromineSolution turned colorlessPotassium PermanganatePurple to brownFTIR Results:Wavenumber (nm)Functional Group619 sharp, shortC-Cl stretch880 sharp, medium=C-H stretch1047 sharp, strongC-F, C-O, C-N stretch1089 sharp, mediumC-O, C-N stretch1380 sharp, shortC-F stretch1458 sharpAromatic C=C stretch2884 weakAlkyl C-H stretch2972.

22 sharpAlkyl C-H stretch3349.65 broadO-H stretch The starting materials appeared to have not been completely consumed. This was shown when a green flame appeared using the Belstein test, indicating the presence of unreacted alkyl halide. The presence of the C-Cl stretch in the FTIR spectrum of the product also indicated the presence of unreacted alkyl halide. Although there is the presence of the =C-H stretch, that shows presence of pentene as well. However, the wavenumbers corresponding to C-F, C-O, C-N and even aromatic =C-H stretch indicates that there is contamination.

GC is also used to confirm the identity and composition of the distillate. Retention time of the peaks in the sample compared to a standard, determines the identity of the peaks. 3. Describe how the Beilstein, Br2 and KMnO4 tests were used and the conclusions drawn from your observations. The Belstein test is a test for alkyl halides. The green flame is indicative of the presence of chlorine in the liquid, thus implying unreacted 3-chloro-3-methylpentane. The bromine test and potassium permanganate test are qualitative tests for alkenes.

The color of the solution changed from brown to colorless, indicating the presence of an alkene in the product (bbc.co.uk, n.d.). The brown precipitate appearing in the solution after the permanganate test also indicates the presence of an alkene functional group (chemguide.co.uk, 2010). 4. Three unique alkene products are possible for the dehydrogenation reaction of 3-chloro-3-methylpentane. Two of the alkenes are related as E and Z isomers. Draw a Newman projection of the reactive conformation that produces the E isomer and a Newman projection that produces the Z isomer assuming an E2 mechanism for both.

Works CitedAlkenes and Potassium Manganate (VII). chemguide.co.uk. 2010. Web. Accessed on 9 Nov 2014.Hydrocarbons: Alkenes. bbc.co.uk. n.d. Web. Accessed on 9 Nov 2014.