Although cyano isn't a very good leaving group (it IS a fantastic nucleophile, however), it is still better than an alcohol. The only way you can make an alcohol a good leaving group is to activate it somehow. Methods range from simple protonation (making [H-OH]+ - water) in an acidic environment, to tosyl-/mesylation to make OTs/OMs, to activation with a phosphorous reagent, etc.
The cyano group (-C≡N) is generally more polar than the bromo group (-Br). This is due to the strong electronegativity of the nitrogen atom in the cyano group, which creates a significant dipole moment. In contrast, bromine, while electronegative, does not create as strong a dipole in comparison to the cyano group's triple bond. Therefore, the cyano group exhibits greater polarity overall.
Alcohol
The main difference between a hemiacetal and a hemiketal is the functional group involved. A hemiacetal forms when an alcohol group and an aldehyde group are involved, while a hemiketal forms when an alcohol group and a ketone group react. Additionally, in a hemiacetal, one oxygen atom is part of the alcohol group and one is part of the aldehyde group, whereas in a hemiketal, both oxygen atoms are part of the alcohol group.
The hydroxyl group (-OH).
CH3OH is called methyl alcohol because it is a type of alcohol compound where the hydroxyl group (-OH) is attached to a carbon atom (methyl group -CH3) in the molecule. This naming convention is based on the IUPAC system for naming organic compounds.
The cyano group (-C≡N) is generally more polar than the bromo group (-Br). This is due to the strong electronegativity of the nitrogen atom in the cyano group, which creates a significant dipole moment. In contrast, bromine, while electronegative, does not create as strong a dipole in comparison to the cyano group's triple bond. Therefore, the cyano group exhibits greater polarity overall.
I think you mean a cyano* group Anyway; the carbon is triple bonded to the nitrogen with a free electron making the cyano group [CN]-
Methyl group is a better leaving group compared to hydride group. This is because methyl group can stabilize the negative charge on the leaving group more effectively than hydride group due to the presence of additional carbon atoms. This makes the departure of a methyl group more favorable in organic reactions.
The prefix cyano- typically indicates the presence of a carbon atom triple-bonded to a nitrogen atom, forming a nitrile functional group. It is commonly found in compounds such as cyanide and cyanocobalamin.
The chemical mechanism of the esterification reaction requires the formation of a tetrahedral intermediate. Upon collapse of said intermediate it is imparative that the leaving alcohol group be protonated. Otherwise it will not make a good leaving group and the alcohol group will be more likely to leave than the hydroxy group. Without the strong sulfuric acid to protonate the alcohol group on the tetrahedral intermediate the reaction essentially reproduces its own reactants again resulting in no observable reaction.
Bromine is a better leaving group than chlorine due to its larger atomic size and lower electronegativity. The larger size of bromine allows for better stabilization of the negative charge that forms when it leaves a molecule, making it more stable and easier to depart. Additionally, the lower electronegativity of bromine means it is less likely to retain the departing electron pair, facilitating the leaving group process.
emigration
emigration
To ensure that "OH" functions effectively as a leaving group in a chemical reaction, one can use a strong acid to protonate the hydroxyl group, making it a better leaving group. This protonation helps stabilize the negative charge that forms when the leaving group departs, increasing the reaction rate and efficiency.
The factors that contribute to determining what makes a better leaving group in a chemical reaction include the stability of the leaving group after it leaves, its ability to stabilize negative charge, and its ability to leave easily. These factors influence the overall efficiency of the reaction and the likelihood of the reaction proceeding smoothly.
Cl- is the superior leaving group because halides form the most stable anions. The stability of an anion reflects its ability to bear a negative charge and accept electrons, which is the function of a good leaving group.
In both SN1 and SN2 reactions, the leaving group's ability to leave impacts the reaction rate. In SN1 reactions, a better leaving group facilitates the departure, leading to a faster reaction rate. In SN2 reactions, a poorer leaving group is preferred as it helps with the concerted mechanism by staying connected longer, resulting in a faster reaction rate.