Essay about Wittig Reaction: Synthesis of Trans-Stilbene

Ethyl ethanoate is made from ethanol and ethanoic acid. In the reaction sulphuric acid is added as a catalyst.

Theory: One of the methods of preparing alkyl halides is via the nucleophilic substitution reactions of alcohols. Alcohols are inexpensive materials and easy to maintain. However, they are a poor leaving group the OH group is a problem in nucleophilic substitution, this problem is fixed by converting the alcohol into H2O.

The reaction involves a nucleophilic acyl substitution on an aldehyde, with the leaving group concurrently attacking another aldehyde in the second step. First the Potassium hydroxide attacks a carbonyl, which forms a tetahedral intermediate which then collapses when attacked by another hydroxide. The carbonyl is formed again when its hydride attacks another carbonyl. In the final step of the reaction, the acid and alkoxide ions formed exchange a proton. In the presence of a very high concentration of base, the aldehyde first forms a doubly charged anion from which a hydride ion is transferred to the second molecule of aldehyde to form carboxylate and alkoxide ions. Subsequently, the alkoxide ion acquires a proton from the solvent.

6. 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; to purify the crude product of either trans-stilbene, cis-stilbene, or styrene reaction.

alcohol (2-methyl-2-butanol, MW _ 88.2, d _ 0.805 g/mL) and 25 mL of concentrated hydrochloric acid (d _ 1.18 g/mL). Do not stopper the funnel. Gently swirl the mixture in the separatory funnel for about 1 minute. After this period of swirling, stopper the separatory funnel and carefully invert it. Without shaking the separatory funnel, immediately open

The reaction is carried out in saturated aqueous ammonium chloride solution. Thus no special drying of solvents, reagents, or glassware is required. The reaction mechanism for this experiment can be seen below (Fig. 2)

The solution that was performed in this experiment was to use sulfuric acid in order to form a protonated alcohol, so when the halogen or nucleophile back attacks the compound, water is displaced. Once the alcohol is protonated, the solution reacts in either an SN1 or SN2 mechanism.

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.

The purpose of this experiment is to convert carbonyl compounds to alkenes using Wittig reaction. In this case we will be synthesizing Trans-9-(2-phenylethenyl) anthracene from benzyltriphenylphosphonium chloride and 9-anthraldehyde. We will also aim to obtaining a high percent yield and purity for the synthesis of Trans-9-(2-phenylethenyl) anthracene. The mechanism for this reaction goes thus:

SN1 reactions are considered unimolecular nucleophilic substitution mechanisms and are a first-order process. Meaning that the reaction forms a carbocation intermediate and that the concentration of the nucleophile does not play a role in the rate-determining step, which is the slowest step in the reaction. All of the SN1 reaction mechanisms in this procedure can react two different ways. The expected mechanism for these reactions would be that the carbocation would react with the weak nucleophile nitrate, attaching the nitrogen to the positively charged carbon. However, while nitrate is the intended nucleophile in all of the reactions, it is a poor nucleophile. The ethanol used in this reaction is a polar protic ionizing solvent,

In this preparative lab, an aldol (trans-p-anisalacetophenone) was produced from the reaction between p-anisaldehyde and acetophenone with the presence sodium hydroxide. The reaction also showed the importance of an enolate and the role it played in the mechanism. Sodium hydroxide acts as a catalyst in this experiment and is chosen because of its basic conditions and pH. The acetophenone carries an alpha hydrogen that has a pKa between 18 and 20. This alpha hydrogen is acidic because of its location near the carbonyl on acetophenone. When the sodium hydroxide is added, it deprotonates the hydrogen and creates an enolate ion. This deprotonation creates a nucleophilic carbon that can attack an electrophilic carbon (like a parent

Determining how a mechanism comes to be is crucial as a scientist and arriving to conclusions is a crucial component which lead to examining and determining which mechanism takes place when two or more substrates are made to react. At the end of the experiment a mechanism was determined based on the purified product’s melting point. This was accomplished by having the reaction take place but also through acquiring the melting point and comparing the number to the melting point which was already established by the scientific community. (Q1) When 0.252 g of trans-cinnamic acid was mixed in 2.5 mL glacial acetic acid and 0.434g pyridinium tribromide was added, the resulting product reflects an addition reaction. In general, reactions take place to achieve its lowest Gibb’s free energy because it’s at

Determining how a mechanism takes place is crucial in order to define a mechanism. In this experiment, a mechanism was determined based on the purified product’s melting point. This was accomplished by comparing the acquired melting point with the one provided by Professor Link. (Q1) When 0.252 g of trans-cinnamic acid was mixed in 2.5 mL glacial acetic acid and introduced to 0.434g pyridinium tribromide, the resulting product reflects an addition reaction. In general, reactions take place to achieve its lowest Gibb’s free energy because it’s at this point where a structure is most stable; in this case, the reaction is an addition of bromine into alkenes. (Q2)

Jimmy Keller was a cancer “quack” with a high success rate by treating cancer with arginine in his proprietary serum. He was convicted of fraud and thrown in jail in 1991, in spite of the fact that he was “quacking” in Mexico. He should’ve been awarded a Nobel Prize, because, since then, various scientists have attempted to describe the complex role of arginine in cancer biology and treatment and found it to be favorable.

Synthetic chemistry and compounds are everywhere in our lives, and without them we would never had technology, medicine, cloth and cars, most probably you are reading this article on a synthetic device. Synthetic chemistry is the base of our life and without it our normal tasks would be impossible to accomplish, as synthetic chemistry opened the doors of creativity and innovation, for example if you got sick in the 1400 with smallpox you would of died in a 2-4 month but now we can easily treat it with synthetic drugs. Today I will be talking about the use of synthetic chemistry more specifically Synthetic drugs in our lives and the affects of it positively and negatively.