The Purpose of this experiment is for the students to learn how to use sodium borohydride to reduce benzil to its secondary alcohol product via reduction reaction. This two-step reaction reduces aldehydes by hydrides to primary alcohols, and ketones to secondary alcohols. In order for the reaction to occur and to better control the stereochemistry and yield of the product, the metal hydride nucleophile of the reducing agents such as LiH, LiAlH4, or NaBH4 must be carefully chosen. Being that LiAlH4 and NaBH4 will not react with isolated carbon-carbon double bonds nor the double bonds from aromatic rings; the chosen compound can be reduce selectively when the nucleophile only react with
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.
Abstract: Using hypochlorous acid to convert secondary alcohol called cyclododecanol to the corresponding ketone which is cyclododecanone by oxidation.
Background: Catalysts are substances that increase the rate of a reaction by providing a different mechanism for the reaction to go through in order to lower the activation energy and are unchanged by the end of the reaction. Enzymes, a specific type of catalyst, are proteins that increase the rate of reaction by converting a substrate to a product in biological processes (Burns, 2002). Enzymes are never used up, but are consistently recycled in order to catalyze many reactions in a certain amount of time. Every enzyme has a specific shape due to the sequence of amino acids, which results in the ability of only a specific substrate to bind to it, whilst others are rejected.
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.
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
The independent variable in this investigation is pH. Each individual enzyme has it’s own pH characteristic. This is because the hydrogen and ionic bonds between –NH2 and –COOH groups of the polypeptides that make up the enzyme, fix the exact arrangement of the active site of an enzyme. It is crucial to be aware of how even small changes in the
In this reaction, a rate-determining step should occur through the ionization between carbon and –OH bond to form an intermediate.11 This step should be followed by rapid reaction of a nucleophile to wrap up the substitution.11 For this experiment, hydrochloric acid was used to drive off the reaction, which contains a chlorine ion, a common nucleophile. (1)Chlorine ion is more effective as a nucleophile than water; because an ion holds a negative charge and resulting in a faster rate of reaction, whereas water holds a neutral charge, resulting in a slower rate of reaction with a carbocation intermediate.13 The starting
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.
Introduction: Enzymes are protein catalysts facilitating the conversion of substrates into products (Alexander and Peters, 2011). They go through a whole chemical reaction which starts off with the substrate and then ends up with a product. The only way this reaction can be adjusted or not even work is if they end up going through some sort of affect which only temperature and pH levels can do determining the environment. When enzymes are in an environment that is too acidic or alkaline, their chemical properties, sizes and shapes can become altered (Magher, 2015) Chemical modification of proteins is widely used as a too; to maintain a native conformation, improving stability (Rodriguez-Cabrera, Regalado, and Garcia-Almendarez, 2011) In this experiment, four trials were conducted and recorded every 15 seconds for 5 minutes in order to calculate the optimum levels and IRV.
Owing to its large acyl pocket, BChE is capable of accommodating larger substrates such as the four-carbon acyl-group of the BCh, making hydrolysis of BCh or the smaller ACh catalytically efficient (Radic et al., 1993). Furthermore, this principle explains why BChE was capable of effectively hydrolysing benzoylcholine which contains a large acyl group in the form of an aromatic ring (Figure1). When compared to AChE, whose acyl pocket is much smaller; BCh, suxamethonium (which contains a large acyl-quaternary nitrogen) and benzoylcholine are unable to effectively fit
This week in lab we focused on reducing Ketones to Secondary Alcohol’s. Hydride reducing agents such as LiAlH4 and NaBH4 react with ketones to produce 2o alcohol. In our experiments, we used NaBH4 as it is a milder reducing agent and can be used in protic solvents such as ethanol. The first week a reaction was carried out using 9-fluorenone as the ketone. And the second my group and I used a variety of ketones to see how they reacted differently.
Also, the enzyme was treated with different urea concentrations before it was added to the assay mixture. The amount of the second and third enzymes was essential. Likewise, this would have had an effect on the rate of the measured aldolase activity. Hence, the concentrations for both enzymes was measured and calculated prior to the experiment whilst preparing the assay mixture. Furthermore, in order to measure thiol group reactivity the base line was adjusted to zero for each cuvette. This was done to make sure that the results were