Since alkenes are immiscible with concentrated HBr, tetrabutylammonium bromide is used as a phase-transfer catalyst. It forms a complex with HBr and extracts it from the aqueous phase into the organic phase where the alkene is. This dehydrates the acid, making it more reactive so that the addition reaction is possible. Rapid stirring is required in order to maximize the surface area
A strong nucleophile/base will likely force a second order reaction because the nucleophile/base is strong enough to attack the electrophilic carbon. In this case, KOtBu is a strong, bulky base and -Br is a good leaving group. Although the Potassium is not crucial to this reaction, the t-butoxide will proceed to attack the single beta hydrogen and knock off bromide to form an alkene, rearranging the bromobutane into an anti-periplanar position. In the KOtBu and 1-bromobutane reaction, there is one beta hydrogen present; this means there is only one possible product, 1-butene. However, there are two different types of beta hydrogens present in 2-bromobutane.
The nucleophile in this particular SN2 reaction was iodine and, as stated before, the leaving groups for 1-bromobutane and 1-chlorobutane are bromine and chlorine respectively. Bromine is a better leaving group than chlorine however, so the fact that 1-bromobutane reacted before 1-chlorobutane corresponds directly with what would be expected. As stated before, primary is more reactive than secondary and even more reactive that tertiary. This explains why no reaction/change was seen for 2-chlorobutane, 2-bromobutane, and tert-butyl-chloride. 2-bromobutane would have been expected to react next, due to bromine being a better leaving group than chlorine, then 2-chlorobutane.
This reaction was able to happen during designated lab time due to the fact that a phenol was used. Phenols or more reactive than unsubstitued benzene rings due to the presence of the alcohol on the benzene ring. The alcohol is considered an activating group due to the oxygen’s ability to donate its lone pairs into the benzene ring thus giving it more electrons and thus making it more nucleophilic and more likely to react with the introduced electrophilic species. As aforementioned, there are various products formed in this reaction the two major products formed though are the ortho and para products. It is debatable which product is more prominent due to steric reasons and the capability of each product to conduct in hydrogen bonding.
They can impart localised structural rigidity, confer cytotoxicity by alkylation, or be secondary metabolites . The chemistry of epoxides is dominated by the reactions that involve opening of the strained three-membered heterocyclic ring by nucleophiles. Such reactions yield valuable bifunctional compounds. In nature, epoxide ring opening is catalysed by the phenolic proton of a tyrosine moiety . But in laboratory, the cleavage usually occurs in non-aqueous media in presence of a Lewis acid catalyst like Al2O3, Li+, Mg2+ etc.
1. Magnesium is an alkaline earth metal with an atomic number of 12 and an atomic mass of 24.305. It is part of the second group of elements on the periodic table located on the far left side of the periodic table. *CAUTION* Magnesium is a flammable metal! The equation for the reaction that is going to happen is: Magnesium + Hydrochloric Acid —> Magnesium chloride + Hydrogen Mg (s) + 2 HCl (aq) --> MgCl 2 (aq) + H 2 (g) This reaction is an Oxidation-reduction.
To analyze the acetanilide product of the reaction, 1H NMR and IR were used. Results, Discussions, and Conclusions In this experiment, acetanilide was synthesized via nucleophilic acyl substitution from both acetic anhydride and aniline. During this reaction, aniline acts as the nucleophile and acyl (CH3CO-) group from acetic anhydride acts as the electrophile. The hydrogen atom of –NH2 group is replaced by the acyl group. The crude product contained acetanilide, and acetic acid, which was the impurity.
All diisocyanate are liquids or solids in the nature and highly reactive, it undergo reaction across the double bond C=N of the –NCO group. The reactivity of the isocyanates are mainly depends on the electron density of the central carbon atom of the isocyanate, the low electron density of central carbon atom contains compounds are highly reactive means the aromatic diisocyanates are highly reactive than aliphatic because of resonance structures. Therefore, the electrophilic nature of the aromatic diisocyanates can alter through different substituents on aromatic ring like electron withdrawing or donating groups. The reactivity of diisocyanates plays important role to synthesis of polyurethanes because the possibility to form dimers, trimmers and higher oligomers and also possible to form polymers. In addition, the number of cross-linking reactions may be take place, mainly depends on the reaction conditions such as temperature, catalysts, the structure of the alcohols, amines and isocyanates.