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Explain Le Chatelier’s principle
Explain Le Chatelier’s principle
Explain Le Chatelier’s principle
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Fischer Esterification is a unique type of esterification first discovered by Emil Fischer and A Speier in 1895. Fischer Esterification is a mechanism of which an ester is formed as a product when a carboxylic acid is treated with an alcohol and an acid catalyst. Together with ester, water is also liberated on this reaction. The key bonds formed in this reaction is C-OR, of which the oxygen bonded to carbon is the oxygen from the alcohol, not the oxygen originally bonded to it from the starting carboxylic acid. The key bonds broken is C-OH, the oxygen from the carboxylic acid bonds with the hydrogens that will then form water. So, the reaction does not simply just break the H and the R but rather -OH and -OR. This reaction is an equilibrium reaction. Applying Le Chatelier’s principle, if alcohol is used as a solvent to carboxylic acid and have a small amount of water (product), then the reaction would favor the product. On the other hand, if the reaction is to go backwards, whereas the reaction would start from an ester going to a carboxylic acid, then the water would be used as a solvent. Common acid catalyst are sulfuric acid, tosylic acid, and Lewis acids such that of scandium(III) triflate. Tertiary alcohols are prone to elimination whereas phenols Non-complicated acidic conditions can be utilized if acid-sensitive functional groups are not an issue; sulfuric acid can be used or even softer acids - for longer reaction tomes. There will be less environmental effect in terms of harmfulness and product wastes of the reagents used because these are straightforward. As per Wikipedia, alkyl halides are greenhouse gasses or ozone depletors, therefore will possibly poison to the atmosphere. Another point was made is that acid anhydrides are more reactive than ester because carboxylate anion is better leaving group than an alkoxide anion because the negative charge is more
The experimental Fischer esterification of 8.92g of acetic acid with 5.0g of isopentyl alcohol using concentrated sulfuric acid as a catalyst yielded 4.83g (65.3% yield) of isopentyl acetate. The product being isopentyl acetate was confirmed when the boiling point during distillation had similar characteristics to that of the literature boiling points2. Physical characteristics like color and smell also concluded a match of our product with what was intended. 1H-NMR spectroscopy analysis supported this claim due to the fact that the integration values and chemical shifts were comparable to isopentyl acetate. Lastly, infrared spectroscopy (IR) showed similar key characteristics of our product’s wavelengths to that of pure isopentyl acetate5.
The theoretical weight was 599.6 mg. This yields a percent yield of 3.7%. Table 1 also illustrates the experimental melting point of 99.3-102.1◦C. A melting point that has a range larger than 3◦C is indicative of impurities in the sample. A few possibilities of impurities could have been unreacted norbornene, and water. Evidence that supports that there was unreacted norbornene in the final sample was the fact that the product was a jelly-like structure. Norbornene by itself has a jelly-like structure. However, once norbornene reacted with the acid-catalyst (H2O2), then it should have changed the chemical structure of the molecule and once the solution was brought back down to room temperature, crystals should have formed. Since a jelly-like, or oil-like product was present at the end of the reaction, then this is indicative that there was unreacted norbornene in the sample. The second impurity that may have been present in the final product was water. Instead of adding 3 mL of sodium bicarbonate and then 3 mL of brine, 3 mL of brine was added first and then 3 mL of sodium bicarbonate was added. This experimental error caused excess aqueous solution to be added to the diethyl ether. Since excess water was added to the final product, about 4x the amount of anhydrous sodium sulfate was needed in order to remove the water from the product. This was another indication that there was too much water in
... which is catalyzed by b-ketoacyl CoA thiolase. The products are acetyl-CoA and a long chain fatty acyl CoA that is 2 carbons shorter than the original fatty acyl CoA. One complete round of β-oxidation cleaves 2 carbons from the fatty acid chain, and the process continues until the entire fatty acid chain is broken down into acetyl propinoyl CoA. For example, an 18 carbon chain fatty acid would need to go through 9 rounds of β-oxidation in order to be completely metabolized.
We are all aware of sugar, the sweet delicious substance commonly used in food and beverages, but table sugar is not the only sugar there is. There are many artificial sugars that many people now-a-days aren’t aware of. In this research paper I will be identifying four different types of synthetic sugars which are: Saccharin, Aspartame, Sucralose, and Sodium cyclamate. Synthetic sugars, or artificial sweeteners, have both positive and negative effects that can either make a big impact in our body or a small impact. Synthetic sugars can be used in many ways but are most commonly used in regular everyday foods and beverages or they can be mixed with other artificial sweeteners. Synthetic sugars tend to look very similar to real sugar so sometimes it may be hard to distinguish them with the naked eye.
Dehydration is defined as a process of removing water from a substance. The loss of water from a molecule is called dehydration which is exactly opposite with the process of hydrolysis. Dehydration is an elimination reaction of an alcohol involves the loss of an OH from one carbon and an H from an adjacent carbon. Overall, this amounts to the elimination of a molecule of water, resulting in a pi-bond formation of an alkene or alkyne. In most of the dehydration of alcohol, heat and catalyze are needed in the reaction. Sulphuric acid (H2SO4) and phosphoric acid (H3PO4) are the most commonly used acid catalysts.
The percentage yield gained was 70% from the Fischer Esterification reaction, which evaluates to be a good production of yield produced as the reaction is known to be reversible where conditions such as the concentration of the reactants, pressure and temperature could affect the extent of the reaction from performing. These white crystalline crystals were tested for impurity by conducting a melting point analysis and taking spectrospic data such as the IR spectra, HNMR and CNMR to confirm the identification of the product. These spectrospic methods and melting point analysis confirmed the white crystalline crystals were benzocaine.
The goal of this experiment is to determine which products are formed from elimination reactions that occur in the dehydration of an alcohol under acidic and basic conditions. The process utilized is the acid-catalyzed dehydration of a secondary and primary alcohol, 1-butanol and 2-butanol, and the base-induced dehydrobromination of a secondary and primary bromide, 1-bromobutane and 2-bromobutane. The different products formed form each of these reactions will be analyzed using gas chromatography, which helps understand stereochemistry and regioselectivity of each product formed.
As a final point, the unknown secondary alcohol α-methyl-2-naphthalenemethanol had the R-configuration since it reacted the fastest with S-HBTM and much slower with R-HBTM. TLC was a qualitative method and ImageJ served as a quantitative method for determining which reaction was the faster esterification. Finally, 1H NMR assisted in identifying the unknown from a finite list of possible alcohols by labeling the hydrogens to the corresponding peaks.
Alternative energy is the world’s race as of now. As the space race concluded and the nuclear arms race died down, alternative energy became the race of the ages. In today’s society, with today’s technology there are all sorts of forms of alternative energies. These energies include hydro power, geothermal, biomass, nuclear power, and so much more. With all of these variations of alternative energy the question now becomes, which form is the best to use? Are any of them safe? Which ones would effectively solve the world’s depleting energy crisis? Of course, the country that is able to produce clean efficient energy; that country would become the new world power virtually overnight. With today’s technology, should we resort to food/corn as our primary source of energy?
Alpha esterases (α-esterases) and beta esterases (β-esterases) were determined according to the methods of Van Asperen (1962) using α-naphthyl acetate and β-naphthyl acetate as substrates, respectively.
...ussion: Adsorption sites for salt as well as for alcohol are polar silanol groups (Fig 1c). As discussed earlier, alcohol is not adsorbed on all silanol groups (prefers isolated silanol group) and alcohol is more preferentially adsorbed than salt. So, anchorage of salt on the silica surface must be very distinct, reducing the possibility of irreducible mixed metal support formation. Also for substantial adsorption, silica gel has to be contacted with very concentrated salt-alcohol solution. In our opinion small amount of water cause ionization of alcohol which further induce ionization at silanol surface creating anionic sites suitable for esterification of ethoxy group. On the other hand, salt is mostly “associated” if the water is around 1-2% in the solution and the adsorbed salt will act as nucleation site for salt present mainly because of physical interaction.
HFCS is a popular sweetener used in processed foods. It is composed of approximately 50% fructose and 50% glucose. It is made from corn starch with the use of enzymes to convert glucose to fructose. It has many advantages over cheap sugar, including, but not limited to, lower price, longer shelf life, low freezing point, and enhanced taste and texture. Corn refinement was first discovered circa 1860, and was soon followed by the development of corn syrup. Important advantages took place in the 1920’s with the use of enzymes, but it was not until the mid-1900’s when the crucial glucose isomerase enzyme was discovered. Industrial production of HFCS began in the 1970’s and today the industry is huge.
The aim of this experiment was to investigate the affect of the use of a catalyst and temperature on the rate of reaction while keeping all the other factors that affect the reaction rate constant.
A condensation reaction is a reaction where two molecules react to form a larger and smaller molecule (Boundless 2016). A type of condensation reaction is an esterification reaction generally when an alcohol reacts with a carboxylic acid. However, esters can also be created from phenols but requires a vigorous ethanoylating agent such as an anhydride (York, 2000). In the synthesis of aspirin, the phenol mentioned is salicylic acid. The structure of a basic phenol is shown in figure 3 and figure 4 shows the structure of salicylic acid where the phenol group can easily be seen. The required anhydride for the reaction is acetic anhydride. Similarly, figure 6 shows the general structure of an anhydride and figure 5 shows the structure of acetic anhydride. It can be clearly seen that the basic structure of an anhydride is present in acetic anhydride. Therefore, the phenol molecule of the reaction is salicylic acid and the anhydride is acetic anhydride, reacting together to produce the ester of acetylsalicylic acid. The structure of acetylsalicylic acid is shown in figure 7, a combination of a phenol and one side of the anhydride. The other side of the anhydride is the second product which is acetic acid; a by-product of the
The production of synthetic detergents are an example of a standard chemical approach. If a useful substance has some undesirable properties an attempt is made to make a near copy synthetically which will perform better.