Introduction:- In organic chemistry the substitution reactions is the most important reactions, especially Nucleophilic aromatic substitution reactions where nucleophile attacks positive charge or partially positive charge As it does so, it replaces a weaker nucleophile which then becomes a leaving group. The remaining positive or partially positive atom becomes an electrophile. The general form of the reaction is: Nuc: + R-LG → R-Nuc + LG: The electron pair (:) from the nucleophile (Nuc :) attacks the substrate (R-LG) forming a new covalent bond Nuc-R-LG. The prior state of charge is restored when the leaving group (LG) departs with an electron pair. The principal product in this case is R-Nuc.
12. The TLC data obtained is provided in a table below. The TLC data was conducted solely in a 9:1 hexane/ethyl acetate solvent solution as opposed to the 1:1 and pure hexane solution as well. This was due to the lack of time, but as explained in number 7, a very polar solvent (1:1 solution) or non-polar solvent (pure hexane) is not ideal when obtaining
The reactants are those substances that changes during a chemical reaction while the products are those that are yield during a chemical reaction. If the chemical reaction is not balanced, we cannot derive the relationship between the products and reactants. So the first thing we should do when we see a chemical reaction is to balance it. How do we balance a chemical equation? Look at this scale; we can see that it is unbalanced wherein the right side weighs more than the left side.
Tertiary alkyl halides tend to give a mixture with both inverted and retained configurations at reaction centers. This is because this reaction proceeds through a stable carbocation intermediate and the carbon at the reaction center goes to sp2 hybridized state (planar geometry). The incoming nucleophile can attack from both sides of the plane and can give two products with retained and inverted configuration. If there is a partial interaction with the leaving group (nucleofuge) with carbocation there will be more product with inverted configuration and if there is no interaction with leaving group racemic mixture can be obtained. The rate of the reaction depends on the formation of a carbocation (which is the slow step) and there is one molecule
Production of powerful oxidant, peroxynitrite (ONOO–) is considered as ‘reactive nitrogen species’ (RNS). Further this may further produce other reactive species similar to hydroxyl radical (•OH) however not always interaction between superoxide radical (•O2–) and nitric oxide (NO•) results in biologically harmful effect. During many enzymatic reaction, SOD-catalysed dismutation form O2 and hydrogen peroxide (H2O2) or it is formed by spontaneously reduction of two molecules of (•O2–). Hydrogen peroxide (H2O2) & superoxide radical (•O2–) enters into the cells in the same way as H2O enters. In the presence of transition metal ions like low molecular mass iron or copper,
Self association due to H-bonds also become weaker due to steric hindrance to H-bond formation in 4-methylpentan-2-ol as compared to Hexan-1-ol which cause more positive VE values for 4-methylpentan-2-ol. The shape of the molecule is another factor which contributes more positive value of VE to 4-methylpentan-2-ol. The Hexan-1-ol molecule is planer and elongated in same fashion as those of n-alkanes. The alignment of these molecules on mixing is ordered due to Vander Waal’s forces. The 4- methylpentan-2-ol molecules are bulky and spherical in shape.
The lack of basicity within amide is due to the C=O, or carbonyl group, within the amide as it has electron withdrawing properties causing the lone pair of electrons within nitrogen to become delocalised. The Amide functional group is also a moderate Electron Donating Group (EDG), meaning that it donates some of its electron density to conjugated
Solvent used in the elution process would be the mobile phase and solvents of different polarity would have a significant impact on the separation due to the varying solubility of compounds in different solvents. Hexane, being the less polar solvent, interacts mainly with the less polar analytes but very slowly with polar analytes. Therefore using hexane at the start of the elution process allows the less polar compound to be eluted out first. After the complete collection of less polar analyte, the mobile phase was changed to the more polar hexane/ethyl acetate solvent, which has stronger interaction with the more polar component, allowing it to be eluted out faster. The change in solvents throughout the elution process would allow for an effective and efficient separation of the compounds β-carotene and chlorophyll in the crude extract of green leaves.
Thirdly, the hydroxyl group influences the cholesterol’s physical shape because its presence makes cholesterol a steroid alcohol. Also, it acts as a pivot point around which the molecule tilts. Furthermore, some researchers also discovered the presence of cholesterol’s hydroxyl group to not be at the end, but in the middle of a polyunsaturated lipid membrane. This seems to be caused by the polyunsaturated lipid membrane’s incapability to be in close proximity with cholesterol’s usually hydroxyl position. Lastly, the hydroxyl group influences cholesterol’s overall function because it helps the molecule regulate the membrane.
126.96.36.199 Chemical Interesterification Chemical interesterification is the process to redistribute the component of fatty acid and glycerol ions to form new gylcerolester with the presence of sodium methoxide as a catalyst. Chemical interesterification is also known as directed interesterification since this reaction is directed to produce a particular type of glyceride (O’Brien, 2009). This process is conducted at mild temperature with a range between 20°C to 100°C. O’Brien (2009) states that only catalyst that is active at low temperature is effective. Besides, he also states that the rate of random rearrangement is crucial since the trisaturated glycerides can precipitate as fast as they are produced in the liquid phase.