Acid-base extraction offers a method to separate the active components of Excedrin based on acidity and what bases they will react with. Acid-base extraction also leads to recrystallization which due to the components forming lattices usually results in pure crystals that can be analyzed with TLC. Acid-base extraction is important because it offers a different way to extract the components of a mixture that does not involving boiling the solution. The lack of temperature dependence is useful for molecules whose solubility in water do not vary significantly with temperature. This extraction method is relevant to separate the components of Excedrin providing pure products without needing to use the stock-room version of the compound.
Dalton’s law, as described before, states that the sum of the partial pressures of each component in a solution – two or more volatile compounds – is equal to the total pressure. As this now includes more than one compound when separating volatile substances from each other, fractional distillation must be used. Fractional distillation, which can be viewed as a series of simple distillations, is a method used to separate volatile impurities from its solvent. The main difference is that a column is introduced between distillation flask and head to separate the liquids from each other. This column – of a large surface area with glass or ceramic – provides ample contact between the vapor and liquid phases.
Hot water is much more efficient at dissolving caffeine then colder water. This is an example of solid/liquid extraction. Next, I added the water-tea mixture to a separatory funnel and added dichloromethane (DCM). DCM is an organic solvent and caffeine is much more soluble in it than compared to water. In turn, the caffeine dissolves into the DCM, which can be extracted later.
Discussions. This method is used to accurately quantify pesticides in water samples. The lyophilization is advantageous to allow the complete of the samples to minimize error. The acetonitrile resulted in 82% - 104% extraction efficiency for Alachlor and Malathion in the water samples. The different solvent gradient was fixed to contain both the physical and chemical properties of the pesticides.
Physically, Poly (ether sulphone) appears as a semitransparent material (with transparency in the range of 76%) on account of its being amorphous. Being amorphous also gives it a higher dimensional stability as it does not shrink too much upon cooling. Poly (ether sulphone) is highly resistant to attack my chemical agents including but not limited to alkalis, acids and various concentrated electrolytes. Poly (ether sulphone) is stable under the pH range of 2 – 14. In addition, Poly (ether sulphone) is stable in oxidizing agents and various non-polar solvents.
RESULTS AND DISCUSSION: Graph 1 Calibration curve for Standard Gallic acid A standard curve of gallic acid was constructed to determine the amount of total phenolic contents in the black grams. The equation for the gallic acid was expressed as y= 0.002x (R2=0.973). The results of the study were expressed as gallic acid equivalent (GAE) in μg/ g of dry weight. Single factor experiments Effect of solvent type on extraction of phenolic compounds Selection of extraction solvents is very important as it has important role in the determination of the amount and the type of phenolic compounds that will be extracted. Aqueous alcohols particularly acetone, ethanol and methanol are usually preferred for the extraction of the phenolic compounds from
As mentioned in number 13, the data for the melting point makes sense because my pure product and given compound almost perfectly matched. 17. Again as explained in number 14, the TLC data made sense because my pure compound and 4-tert-butylbenzyl phenol had similar distances from the solvent origin of the plate. The presence of benzyl bromide and benzyl alcohol also explains how not all the product dissolved in the filtrate. The possible explanations and changes to make are similar to the previous questions.
GC-MS (Gas Chromatography-Mass Spectrometry): GC (Gas Chromatography): Gas chromatography is a method which is used for the separation and analysis of organic compounds (i.e. volatile compounds). For separation prime factor is volatility i.e. more volatile compounds elute first from the column and then detected by detector. It is used for testing the purity and isolating of compounds.
EXPERIMENT Polyol process is used for the synthesis of the nanoparticles. A polyol is an alcohol containing multiple hydroxyl groups. This process involves hydrolysis and inorganic polymerization carried out on the salts dissolved in a polyol medium. The polyol acts as a solvent for the precursor salts because of its high relative permittivity, and allows one to carry out hydrolysis reactions under atmospheric pressure in a large temperature range up to the boiling point of the polyol. Ethylene glycol has been widely used in the polyol process for the synthesis of metal (pure and alloyed) nanoparticles due to its strong reducing power and relatively high boiling point (~1970C).
The acid-catalysed dehydration of a secondary and primary alcohol revealed that the E1 mechanism undergoes and favors rearrangement for a more stable carbocation; this reaction favors a Zaitsev product, which attacks the most substituted beta hydrogen. The base-induced dehydration of a secondary and primary bromide undergoes an E2 mechanism and favors a Hoffman product because of the presence of a sterically bulky base, which attacks the least substituted beta hydrogen. The percent compositions obtained through Gas Chromatography revealed that these favored types of products were present in the highest