Compare The Three Possible Products That Occur During An Electrophilic Aromatic Substitution Reaction

The objective of this laboratory experiment is to study both SN1 and SN2 reactions. The first part of the lab focuses on synthesizing 1-bromobutane from 1-butanol by using an SN2 mechanism. The obtained product will then be analyzed using infrared spectroscopy and refractive index. The second part of the lab concentrates on how different factors influence the rate of SN1 reactions. The factors that will be examined are the leaving group, Br – versus Cl-; the structure of the alkyl group, 3◦ versus 2◦; and the polarity of the solvent, 40 percent 2-propanol versus 60 percent 2-propanol.

Purpose: The purpose of this experiment is to observe a variety of chemical reactions and to identify patterns in the conversion of reactants into products.

1. Purpose: to clarify the mechanism for the cycloaddition reaction between benzonitrile oxide and an alkene, and to test the regiochemistry of the reaction between benzonitrile oxide and styrene.

A unimolecular nucleophilic substitution or SN1 is a two-step reaction that occurs with a first order reaction. The rate-limiting step, which is the first step, forms a carbocation. This would be the slowest step in the mechanism. The addition of the nucleophile speeds up the reaction and stabilizes the carbocation. This reaction is more favorable with tertiary and sometimes secondary alkyl halides under strong basic or acidic conditions with secondary or tertiary alcohols. In this experiment, the t-butyl halide underwent an SN1 reaction. Nucleophiles do not necessarily effect the reaction because the nucleophile is considered zero order, (which makes it a first order reaction.) The ion that should have the strongest effect in an SN1 reaction is the bromide ion. The bromide ion should be stronger because it has a lower electronegativity than chloride as well as a smaller radius.

The purpose of this experiment is to examine the reactivities of various alkyl halides under both SN2 and SN1 reaction conditions. The alkyl halides will be examined based on the substrate types and solvent the reaction takes place in.

Aromatic compounds can undergo electrophilic substitution reactions. In these reactions, the aromatic ring acts as a nucleophile (an electron pair donor) and reacts with an electrophilic reagent (an electron pair acceptor) resulting in the replacement of a hydrogen on the aromatic ring with the electrophile. Due to the fact that the conjugated 6π-electron system of the aromatic ring is so stable, the carbocation intermediate loses a proton to sustain the aromatic ring rather than reacting with a nucleophile. Ring substituents strongly influence the rate and position of electrophilic attack. Electron-donating groups on the benzene ring speed up the substitution process by stabilizing the carbocation intermediate. Electron-withdrawing groups, however, slow down the aromatic substitution because formation of the carbocation intermediate is more difficult. The electron-withdrawing group withdraws electron density from a species that is already positively charged making it very electron deficient. Therefore, electron-donating groups are considered to be “activating” and electron-withdrawing groups are “deactivating”. Activating substituents direct incoming groups to either the “ortho” or “para” positions. Deactivating substituents, with the exception of the halogens, direct incoming groups to the “meta” position. The experiment described above was an example of a specific electrophilic aromatic

The mechanism by which trimethylphenol is formed is a carbonyl addition mechanism. The overall reaction is summarized in Figure 3. The carbonyl carbon on the benzphenon is weakly electrophilic and is attacked by carbanionic carbon of the Grignard reagent, phenylmagnesium bromide. This attack causes the carbonyl oxygen to assume a -1 charge as a sp3 bonded oxygen. The magnesium from the Grignard reagent then forms a complex with the oxygen and a mild acidic workup is added to protonate the oxygen to release it from the magnesium complex.

This experiment takes a longer time then other experiments, taking approximately three weeks to complete. It involves a three-step synthesis to make pnitroaniline from aniline and then we will be characterizing our product using the new and useful technique of thin layer chromatography (TLC). We will not be doing the first part of this experiment only parts two and three. Electrophiles are reagents which are attracted to other electrons and in order to bond to nucleophiles, they accept electron pairs. Electrophiles attack benzene and this results in hydrogen substitution.

Three carbon-carbon forming reactions—barbier, wittig, and aldol— were performed in order to analyze which reaction had a more green-chemistry approach. Carbon-carbon bond forming reactions are important in organic synthesis because they allow construction of the desired product. The similarities of these carbon-carbon forming reactions were that they all used a type of aromatic benzaldehyde, which was a reactive, easy to work with organic compound. In contrast, the wittig reaction was solventless, while the barbier and aldol reactions were not. Scheme 1 represents the carbon-carbon forming barbier

iii. Substitution reactions: In a substitution reaction, one atom is swapped with another atom. These are very useful reactions in the chemical industry because they allow chemists to change one compound into something more useful, building up designer molecules like drugs. Methane reacts with chlorine (or bromine) in the presence of sunlight or a halogen-carrier to give haloalkene, in which one or more H-atoms are replaced by equal number of halogen atoms.

The order of EAS rates, from fastest to slowest, is as follows: phenol, 4-bromophenol, anisole, acetanilide, and diphenyl ether.

This section of the report discusses the final products, including their toxicity and their final fate. In general, the whole chemical reaction mechanism can be divided into four overlapping processes: 1) H-abstraction by OH radical, 2) O2-addition, 3) O-transfer by using NO, 4) bond cleavage or formation of the double

This difference can lead to differing yields in the products of interest. In this case, what is to be determined is which Lewis-acid catalyst produces higher yields of diphenyl sulfoxides. Previously, aluminum-chloride-catalyzed Friedel-Crafts (EAS) reactions of thionyl chloride (SOCl2) with benzene (PhH) were conducted. Thionyl chloride readily combines with AlCl3 to produce diphenyl sulfoxide, mainly when mixed in 2:1:1 molar ratio (Sun, Haas, McWilliams, Smith, & Leaptrot, p.1). Thionyl chloride and aluminum chloride combine via a OAl coordination bond forming 1:1 zwitterionic adduct Cl2SO+--AlCl3 (Sun, Haas, Sayre, & Weller, p.1). What has not been performed yet is a similar reaction involving iron(III) chloride (FeCl3). The FeCl3-catalysed Friedel-Crafts (EAS) reactions with thionyl chloride and benzene will optimistically produce different yield percentages of diphenyl sulfoxides and diphenyl sulfides than that of the AlCl3-catalysed reactions. Hopefully, the study of these reactions will lead to better knowledge of how Lewis-acid catalysts play a role in electrophilic aromatic substitution reactions. The reactions will be performed at various temperatures (-10°C, 0°C, 25°C,45°C, 70°C) and have differing mole ratios (2:1:1, 3:1:1), which will produce dissimilar product yields. The reagents will also be mixed in various ways, and the purpose of this is to see which order of mixing

As the reactions show, the unpaired electron chops the double bond between the carbon atoms in ethylene, turning it into longer and longer free radicals.

Aromatic compounds tend to undergo electrophilic aromatic substitutions rather than addition reactions. Substitution of a new group for a hydrogen atom takes place via a resonance-stabilized carbocation. As the benzene ring is quite electron-rich, it almost always behaves as a nucleophile in a reaction which means the substitution on benzene occurs by the addition of an electrophile. Substituted benzenes tend to react at predictable positions. Alkyl groups and other electron-donating substituents enhance substitution and direct it toward the ortho and para positions. Electron-withdrawing substituents slow the substitution and direct it toward the meta positions.