Wait a second!
More handpicked essays just for you.
More handpicked essays just for you.
Experiment gas chromatography thesis
Experiment gas chromatography thesis
Don’t take our word for it - see why 10 million students trust us with their essay needs.
Recommended: Experiment gas chromatography thesis
Elizabeth Ochoa | 15492972 Post Lab | 40862
INTRODUCTION
Elimination Reactions and Gas Chromatography Reagents undergo different mechanisms when made to react depending on temperature exposure and the type of solvent used. Elimination, substitution, and addition reactions are constantly in competition with each other. However, when these same reagents are made to interact under high temperatures, the products predominantly observed are elimination products. Ultimately, through this experiment different reagents are going to be used and exposed to different conditions. Predominant products are going to be present but part of the products will include the minor products. The best way to determine the ratio of major to minor products would be through the Gas Chromatography analysis.
THEORY
…show more content…
This type of reaction encourages the formation of C-C π bond by breaking two single bonds to carbon where one of them is a hydrogen atom and the other is typically a halide atom. The type of reaction it undergoes is mainly indicated by the type of alkyl halide(electrophile) it starts off as: a primary alkyl halide versus a secondary alkyl halide. The type of elimination reaction (1 or 2) is dictated by the type of strong base it is presented with; bulky versus non-bulky. Elimination 2 takes place when a primary alkyl halide reacts with a branched base. Also, in primary alkyl halides elimination and substitution reactions are in competition with each other. However, two of the electrophiles in the experiment are secondary alkyl halides which means E1 and E2 are in competition with each other and in competition with substitution reaction 1 and 2. The main differences between elimination reaction 1 and 2 are as follows: in E1 rate of reaction depends
The competing enantioselective conversion method uses each enantiomer of a kinetic resolution reagent, in this case R-HBTM and S-HBTM, in separate and parallel reactions, where the stereochemistry of the secondary alcohol is determined by the rate of the reactions. When using the CEC method, the enantiomer of the secondary alcohol will react with one enantiomer of the HBTM acyl-transfer catalyst faster than with the other HBTM enantiomer. The mnemonic that identifies the absolute configuration of the secondary alcohol is as follows: if the reaction is faster with the S-HBTM, then the secondary alcohol has the R-configuration. In contrast, if the reaction is faster with the R-HBTM, then the secondary alcohol has the S-configuration. Thin layer chromatography will be used to discover which enantiomer of HBTM reacts faster with the unknown secondary alcohol. The fast reaction corresponds to a higher Rf spot (the ester) with a greater density and a slower reaction corresponds to a lower Rf spot with high de...
Reacting 1-butanol produced 2-trans-butene as the major product. 1-butanol produces three different products instead of the predicted one because of carbocation rearrangement. Because of the presence of a strong acid this reaction will undergo E1 Saytzeff, which produces the more substituted
The unknown bacterium that was handed out by the professor labeled “E19” was an irregular and raised shaped bacteria with a smooth texture and it had a white creamy color. The slant growth pattern was filiform and there was a turbid growth in the broth. After all the tests were complete and the results were compared the unknown bacterium was defined as Shigella sonnei. The results that narrowed it down the most were the gram stain, the lactose fermentation test, the citrate utilization test and the indole test. The results for each of the tests performed are listed in Table 1.1 below.
The spots moved 3.8cm, 2.3cm, 2.1cm, 1.8cm, and 2.5 cm, for the methyl benzoate, crude product, mother liquor, recrystallized product, and isomeric mixture, respectively. The Rf values were determined to be.475,.2875,.2625,.225, and.3125, for the methyl benzoate, crude product, mother liquor, recrystallized product, and isomeric mixture, respectively. Electron releasing groups (ERG) activate electrophilic substitution, and make the ortho and para positions negative, and are called ortho para directors. In these reactions, the ortho and para products will be created in a much greater abundance. Electron Withdrawing groups (EWG) make the ortho and para positions positive.
The positive charge on the phosphorus atom is a strong EWG (electron-withdrawing group), which will trigger the adjacent carbon as a weak acid. 5 Very strong bases are required for deprotonation such as an alkyl lithium, however in this experiment 50% sodium hydroxide was used as reiterated. Lastly, the reaction between ylide and aldehyde/ketone produces alkene. (Eq. 1) As shown in equation 2, the reaction between the phosphonium salt and the sodium hydroxide produces the ylide/carbanion that is stabilized due to the positive charge on phosphorus and the conjugation that occurs in the benzene ring as shown by the structure B in equation 2.
Every 5 minutes, a small amount of mixture was dissolved in acetone (0.5 mL) and was spotted onto a thin layer chromatography (TLC) plate, which contained an eluent mixture of ethyl acetate (2 mL) and hexanes (8 mL). The bezaldehyde disappearance was monitored under an ultraviolet (UV) light. Water (10 mL) was added after the reaction was complete, and vacuum filtrated with a Buchner funnel. Cold ethanol (5 mL) was added drop-by-drop to the dried solid and stirred at room temperature for about 10 minutes. Then, the solution was removed from the stirrer and place in an ice bath until recrystallization. The recrystallized product was dried under vacuum filtration and the 0.057 g (0.22 mmol, 43%) product was analyzed via FTIR and 1H NMR
The reaction performed in this experiment was bromination of an alkene, using trans-Cinnamic acid, Pyridinium Tribromide, and Glacial Acetic Acid.
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 “tetrahydido” in the names mean that there are four hydrogens around the aluminium or boron in the negative ion. The structures for both reducing agents contain negative ions and there are empty orbitals on the aluminium or boron due to the co-co ordinate covalent bonds which use lone pairs of electrons from the hydride ion. The same principles would go to the reduction of aldehydes and ketones where you get the same organic compound. It does not matter whichever reducing agent is used. In the reaction of nucleophilic addition, the aldehyde and the ketone act the same way.
Discussion: E-stilbene is a molecule molecule consisting of carbon-carbon double bond with a phenyl functional group attached to each carbon on opposite sides of the double bond. Thus, since this molecule is an alkene, the electrophilic addition of bromine causes the bromine to break and add to the carbon carbon double bond. This mechanism essentially can be considered to have two routes, but three different products. One route will use from a three membered ring (cyclic) with a bromine cation, which will in turn from a meso product (Meso-stilbene dibromide) due to the Sn2 (2nd order bimolecular) addition of bromine, as bromine can only attack the carbon from the opposite side. The meso product has a 1R 2S configuration at its stereoisomers.
If under normal conditions, when the nucleophilic nitrogen attacks, it will attack the cyclohexanone. If under rigorous conditions, the nitrogen will attack 2-furaldehyde. This is due to the carbon on cyclohexanone being secondary (i.e. more stable) than the primary carbon of 2-furaldehyde. The trend observed is thermodynamic control seem to effect primary carbons, whereas, kinetic control seem to effect secondary carbons. Under thermodynamic control the intermediate seems the most unstable. The kinetic controlled intermediate seems the least unstable of the two.
Fractional Distillation and Gas Chromatography 6. Data and Results Reference Attached Pages 7. Discussion The purpose of this experiment was to identify the chemical constituents of an unknown solution and its ratio.
The tests explained above and completed to aid in the determination of the unknown bacteria were completed in a specific order which was supported with rationale and logic. A T – streak method was completed in succession to obtain a pure isolated colony. The T – streaks were completed with nutrient agar to give the organism nutrients and allow the organism to grow. Once a pure isolated colony was obtained, a Gram stain was completed which gave the Gram reaction and morphology of the bacteria.
The area of chemistry that deals with the study of reaction rates and their mechanisms is called chemical kinetics. Chemical kinetics also helps to define the condition in which the reaction rate can be reformed. Temperature, concentration and catalysts are factors that are considered to affect the rate of a chemical reaction. In this experiment, the objectives are to measure the rate of the decomposition of H_2 O_2 (Hydrogen Peroxide), with the presence of the catalyst KI (Potassium Iodide), determine the kinetic order of both reactants, and find the calculations for the activation energy of the reaction. The pressure above a mixed solution of H_2 O_2 and KI with numerous concentrations and temperatures were observed over four different trials
Kuhn and A. Winterstein) published a paper (Ettre & Sakodynskii, 1993) on purification of xanthophylls on CaCO3 adsorption column following the process described by Tswett. In the year 1941, partition chromatography was discovered by R. L. M. Synge and A. J. P. Martin at Cambridge University in the UK, (Martin & Synge, 1941) for that in 1952 they were awarded the Noble Prize. In 1952, Martin and Synge published a seminal paper (Martin, 1941) which, along with the paper of A.T. James and A. J. P. Martin (Martin & Synge, 1952), laid a foundation for the quick growth of chromatographic techniques that shortly followed. Prior to the 1970's, few good chromatographic methods were commercially obtainable to the laboratory scientist. During 1970's, most chemical separations were performed using different techniques including open-column chromatography, TLC (thin-layer chromatography) and paper chromatography. However, these chromatographic techniques were insufficient for resolution between similar compounds and quantification of compounds. During this time, to decrease flow-through time pressure liquid chromatography began to be used, thus reducing time taken for purification and separation of compounds being isolated by column chromatography. As flow rates were Inconsistent, the question if it was good to have a constant flow rate or constant pressure was debated (Chatrabhuji et al., 2015). In the mid-1970's, High pressure liquid chromatography (HPLC) was developed and improved rapidly with the development of different column packing materials and the additional suitable detectors. Some new methods including reverse phase liquid chromatography allowed for better separation between very similar molecules. By 1980's, for the separation of chemical molecules, HPLC was widely used. New techniques enhance purification, separation,