Cholesterol is a steroid alcohol that is constituted as a nonsaponifiable lipid. All steroids play an important role in the secretion of blood in which is vital for the human body to function properly. The carbon-carbon double bond in cholesterol makes the molecule as a whole immensely more reactive than other alkanes. Cholesterol’s ability to be reactive allows it to be capable of undergoing addition reactions because the pi bond electrons can easily bond to other atoms. The addition of a halogen, in this experiment, bromine, creates a vicinal dibromide. The mechanism behind this addition reaction begins with the bromine-bromine bond breaking due to an attack by the alkene nucleophile. This also ensures that bromine does not end up with more …show more content…
The solution is pale yellow in color, and from this it is assumed that the bromine is in excess and the cholesterol is the limiting reagent. The cholesterol dibromide solution is placed in an ice bath, the reason behind this is that the colder the environment is, the less soluble the solution becomes, therefore, the cholesterol dibromide begins to crystallize. In this experiment, it took a while for the cholesterol dibromide to fully crystallize, so acetic acid was added as a precipitant. A wash solution is prepared which consisted of acetic acid and methyl tert-butyl ether to rinse the flask for the solid cholesterol dibromide that was stuck to the flask. Cholesterol dibromide was isolated by using the vacuum filtration technique. Before the cholesterol dibromide was vacuum filtered it was a solid sticky white paste. Cholesterol is the limiting reagent, meaning the original amount of cholesterol that the experiment started with, should be equivalent to the number of moles of cholesterol dibromide, if the reaction was completed. In this experiment, the theoretical yield for cholesterol dibromide was 170 mg, but the actual amount recovered was 81 mg, giving a 48% yield. The literature melting point of cholesterol dibromide is 105℃ and the melting range from the recovered
Reflux condensation was performed with use of a heating mantle and retort stand. A total of 20 minutes was allocated for reflux, starting when the mixture first began signs of boiling(T0), to when the allocation of time was depleted(T20). The mixture was filtered into a 50mL conical flask, and 10mL of 100°C water. The extract was subsequently allowed to cool to room temperature, and decanted into a separating funnel. Liquid-Liquid (Polar-Nonpolar) extraction of DCM
• The solution was then heated gently until the solution begins to distil and that is when the first temperature was recorded. • Samples were collected every (3 mL) using sample vials and the temperature was recorded during each fraction. • The distillation was stopped when (3 mL) of the solution was left in the distillation flask because letting it boil
25 mL of a 1 M phenyl magnesium bromide in tetrahydrofuran was dispensed into the beaker by using a syringe. The resulting mixture was stirred for about 15 minutes when the purple color turned into a brown color permanently. It was then extracted first with 20 mL of dichloromethane and the bottom DCM layer containing the product was reextracted with 10 mL of dichloromethane. The final bottom layer was retained and dried with MgSO4. The drying agent was discarded when the mixture was filtered.
The main objective of this experiment was to isolate the compounds in a given mixture, which was composed of 50% fluorene, 40% o-toluic acid, and 10% 1, 4-dibromobenzene. Techniques of extraction and crystallization was used to perform the separation. The experiment was separated into two parts; each part was to isolate a major compound from one another. The two major compounds (fluorene and o-toluic acid) were also collected. The o-toluic acid was extracted first by using macroscale extraction and by testing for acidity.
Kolbe-Schmitt Reaction Kira Wall (CHE433) 12-3-14 The Kolbe-Schmitt reaction is named after Hermann Kolbe and Rudolf Schmitt. Schmitt published his research in the Journal fur Pracktische Chemie in 1885 while Kolbe published his research in the Annalen der Chemie und Pharmacie in 1860. The reaction adds a carboxyl group onto the benzene ring of a phenol.
One thermometer was then placed into the 20mL of water in each graduated cylinder and left to sit at room temperature. When both thermometers reached the same temperature (the assumed ‘room temperature’), the water from one graduated cylinder was transferred into a 100mL beaker. The water from the other graduated cylinder was poured into a polystyrene cup. Using a scale and a weighboat, precisely 2 grams of ammonium chloride (NH4Cl) was measured and placed into the polystyrene cup with the 20mL of water. The chemical compound and the water were mixed together using a glass rod until the chemical was thoroughly dissolved.
H H Cl 32 34 35 32 33 10 Mono-halogenation (-Cl, -I, -Br) of isatin (32) can be achieved by reacting Nhalosaccharins 36 with isatin in the presence of SiO2 at r.t to specifically produce the 5-halo derivatives 37 as reported by de Silva and de Mattos.20 This method is an alternative to the use of highly toxic and corrosive Cl2 and Br2, which can lead to other products such as 5,7-dibromo- 3,3-dialkoxyoxindole when the bromination of isatin is attempted in alcoholic media.22 N O O SiO2 CH2Cl2 , rt. + N O O H H X S N O O O X X
Introduction Distillation is a specific technique of separating mixtures based on differences in propensity to vaporize of components in a boiling liquid mixture (Palleros, 2000). Distillation is a physical separation process, which does not involve chemical reaction and used for purification of liquids which do not undergo decomposition at their boiling point. There are several types of distillation including simple distillation, fractional distillation, vacuum distillation and steam distillation (ibid.). The type of used distillation depends on the nature of the liquid and the nature of impurities present in it. During this practical two types of distillation were performed: simple and fractional distillation.
1) Sodium Chloride’s melting point is 800.7° which matches the observation acquired for this compound. Sucrose’s melting point is 185.5° which also resembles the results from the experiment. Glycerin’s melting point is 18.1° which is very logical since Glycerin is a liquid at room temperature. The only discrepancy is sodium hydrogen carbonate’s melting point, which is 50°, this does not match the recorded results, because sodium hydrogen carbonate was still in solid form when sucrose was changing state (suggesting that it possesses a higher melting point than 186°).
Resulting in the experiment that the unknown compound was chorine. Introduction As a groups to identify an unknown compound, we need to know its physical properties (color, state and smell). David brought all the compound that are need to for the project and
The purpose of this lab was to determine the melting and freezing point of an unknown (Q) substance and to identify the unknown substance based on the melting and freezing properties. First, to start the lab, a double ring system was set up for a hot water bath. Next, unknown Q was examined and observations about the solid were taken at the lab station. Next, a test tube that contained unknown Q was placed onto a test tube clamp.
7) Discussion: The goal of this experiment was to covert 1-butanol into 1-bromobutane. By reacting 1-butanol with bromine, a nucleophilic substitution would occur where the alcohol group from 1-butanol is replaced with a bromine. In order for the -OH group to depart, its conjugate acid would have to be a strong acid. The conjugate acid for a hydroxyl group is water, which is a weak acid.
After the nucleophilic substitution, the nucleophile can be neutral or carry a negative charge while the substrate can be neutral or positively charged. In this lab, a primary alcohol is converted to an alkyl bromide and a benzyl chloride into an ester using the SN2 reaction. Factors affecting the rates of both SN1 and SN2 reactions will also be investigated. In 1935, two scientists by the names of Sir Christopher Ignod and Edward D. Hughes, studied nucleophilic reactions of alkyl halides.
INTRODUCTION: Lipase also called as triacylglycerol acylhydrolaseis an enzyme known for its enormous applications for industry and diagnostics. Their basic activity is to convert fats into fatty acids and glycerol. These enzymes are water soluble in nature. They also convert polar solvents into more lipolytic substances.
Fractional distillation was performed in this lab to separate a mixture of two miscible liquids with a difference in boiling points of less than 40 C, and to predict their identities. After that, gas chromatography was used to confirm the identities of the two liquids in the unknown solution, and to obtain the ratio of the composition of the solution with respect to these two liquids. Distillation is a separation technique that relies on two substances having different boiling points, so that one evaporates and condenses in a separate flask. Simple distillation can be used for mixtures of solids and liquids, as liquids typically have lower boiling points than solids, or for mixtures of two liquids with a difference in boiling points greater