In organic and inorganic chemistry, nucleophilic substitution reactions are the most well studied and useful class of reactions. These reactions can occur by a range of mechanisms, the two studied in this lab are the SN1 and SN2 reactions. In a nucleophilic substitution, the nucleophile is a electron rich chemical species which attacks the positive charge of an atom to replace a leaving group. Since nucleophiles donate electrons, they are defined as Lewis bases. The positive or partially positive atom is referred to as an electrophile. The whole molecule which the electrophile and the leaving group are part of is called the substrate. The most general form of the reaction is represented as the following: Nuc: + R-LG → R-Nuc + LG: The lone pair on the nucleophile would attack the (R-LG) substrate, forming a new bond with the (R) resulting in the (LG) leaving the substrate with a lone pair. The product formed after the nucleophilic attack is (R-Nuc). After the nucleophilic substitution, the nucleophile can be neutral or carry a negative charge while the substrate can be neutral or positively charged. In this lab, a primary alcohol is converted to an alkyl bromide and a benzyl chloride into an ester using the SN2 reaction. Factors affecting the rates of both SN1 and SN2 reactions will also be investigated. In 1935, two scientists by the names of Sir Christopher Ignod and Edward D. Hughes, studied nucleophilic reactions of alkyl halides. Ignod first grouped organic reactions
The better the leaving group, the faster the reaction making Br a better leaving group than Cl. Tertiary-butyl iodide reacts faster than tertiary-butyl bromide via S_N 2 mechanism because iodide is a better leaving group than bromide. True or False? True. 1-Chlorobutane (2.5 mL, d=0.886) in 20 mL of acetone is reacted with 90 mL of a 15 wt% solution of NaI in acetone.
In this test, primary halides precipitate the fastest while secondary halides need to be heated in order for a reaction to occur. Comparison of the rates of precipitation of the obtained product to standard 1° and 2° bromide solutions will show whether the product is a primary or secondary
Aims of experiment • Determine the rate constants for hydrolysis of (CH3)3CCl in solvent mixtures of different composition (50/50 V/V isopropanol/water and 40/60 V/V isopropanol/water) • Examine the effect of solvent mixture composition on the rate of hydrolysis of (CH3)3CCl Introduction With t-butyl chloride, (CH3)3CCl, being a tertiary halogenoalkane, it is predicted that (CH3)3CCl reacts with water in a nucleophilic substitution reaction (SN1 mechanism), where Step 1 is the rate-determining step. The reaction proceeds in a manner as shown
Chem 51LB Report Ngoc Tran - Student ID # 72048507 The purpose of this lab is to examine the composition of three components of gas products of elimination reaction under acidic condition by conducting the dehydration of primary and secondary alcohol, and under basic condition by conducting the base-induced dehydrobromination of 1-bromobutane and 2-bromobutane. Then gas chromatography is used to analyze the composition of the product mixtures. Gas chromatography (mobile phase) is used to analyze the composition of three components of the gas products. A syringe needle with gas product is injected into the machine, and the component is eluted and the composition is related to the column or the peaks.
The purpose of this experiment was to learn about the electrophilic aromatic substitution reactions that take place on benzene, and how the presence of substituents in the ring affect the orientation of the incoming electrophile. Using acetanilide, as the starting material, glacial acetic acid, sulfuric acid, and nitric acid were mixed and stirred to produce p-nitroacetanilide. In a 125 mL Erlenmeyer flask, 3.305 g of acetanilide were allowed to mix with 5.0 mL of glacial acetic acid. This mixture was warmed in a hot plate with constantly stirring at a lukewarm temperature so as to avoid excess heating. If this happens, the mixture boils and it would be necessary to start the experiment all over again.
How can someone explain the relationship between a chemical engineer and his job? It’s pure chemistry! Chemical engineers work with chemicals to develop new products. They may engineer a more efficient source of fuel. When engineering this, they would calculate emissions that are released when the fuel is used.
Chem 51 LB Experiment 3 Report Scaffold: Bromination of Trans-Cinnamic Acid 1. The goal of this experiment was to perform a halogenation reaction through the addition of two bromides from pyridinium tribromide. This was accomplished by reacting trans-cinnamic acid with pyridinium tribromide. After the reaction took place, melting point analysis was conducted to find out the stereochemistry of the product, which could either be syn-addition, anti-addition, or syn + anti-addition. 2.
Nevertheless, the latter is not used in this experiment since it is very reactive and extremely flammable. On the contrary, NaBH4 is relatively mild and it can be used with protic solvents. In this manner, 1.507 grs of the ketone 9-fluorenone were mixed with 30.0 ml of 95% ethanol in a 125 ml Erlenmeyer flask. The bright yellow mixture was stirred during 7 minutes until all the components were dissolved.
Next, the oxygen is protonated from the 3-nitrobenzaldehyde, which is then followed by an elimination reaction where this acts as a leaving group. The product is the trans-alkene present in the product. After the reaction was completed, purification of the product was conducted using semi-microscale recrystallization.
Lab Report Experiment 6 Rates of Chemical Reactions By Nikhola Mirashirova Lab Partner: Dina Abetova Section 3, Saturday October 31, 2015 Introduction Rate reaction is the measure of the change in concentration of the reactants or the change in concentration of the products per unit time.1,2 Rate law for this experiment: Rate = k(I-)m(BrO3-)n(H+)p There are several factors which affect the rate of reaction: catalyst, reactant concentration, and temperature.1,2 A catalyst is a substance that changes, increases or decreases, the rate of a chemical reaction but is not being used up during the reaction.3 It provides an alternative way, so that the rate of reaction changes.4 Catalyst, which is used in this experiment, is (NH4)2MoO (0.5 M).
For the last 5 decades, electronics coupled with organic chemistry has been an area of great research interest, especially in physics and chemistry. Until a few years ago, this topic was thought to have no practical approach and was believed to be just research-oriented. Modification of chemical structures so that they can in a way enhance the properties of these when used for electronic applications- especially as a thin film has gained major impetus. It was always thought that organics would soon replace the semiconductors in the near future; given that they could perform the same functions and applications as the semiconductors. However, their stability and efficiency posed a great problem then.
In nucleophilic substitution reactions, there are two possibilities, either Sn1 or Sn2. In this particular experiment, an Sn2 reaction
It is understood the mechanism is acid-catalyzed where protons coordinate with the carbonyl oxygen to make the carbonyl carbon more electropositive for nucleophilic attack (Scheme 1). In the experimental procedure all reactants were added together, this is inefficient as the protons can coordinate with either trans-cinnamic acid or methanol. Coordination with methanol is unnecessary as it reduces its nucleophilicity and makes less protons available to coordinate with the carboxylic acid. To improve
Hypothesis: To determine whether to use organic or inorganic food and textiles based on their quality, price, effect on yourself and the environment. When our parents were younger, there was no choice when it came to buying organic food and textiles as food was produced with pesticides to increase the quantity and availability of agriculture. Nowadays, we do have a choice as more supermarkets, clothing stores and greengrocers stock organic food and textiles.
Bromination is a type of electrophilic aromatic substitution reaction where one hydrogen atom of benzene or benzene derivative is replaced by bromine due to an electrophilic attack on the benzene ring. The purpose of this experiment is to undergo bromination reaction of acetanilide and aniline to form 4-bromoacetanilide and 2,4,6-tribromoaniline respectively. Since -NHCOCH3 of acetanilide and -NH2 of aniline are electron donating groups, they are ortho/para directors due to resonance stabilized structure. Even though the electron donating groups activate the benzene ring, their reactivities are different and result in the formation of different products during bromination.