Laboratory Report on Esterification Essay
Laboratory Report on Stratification Ramshackle Ramona Mae S. Restaurant BBS Chem.
.-2 Abstract: This report presents the process of producing an ester, specifically isopleths acetate. Esters are derivatives of carboxylic acids in which the call carbon bears an alkyl substitutes (-OR) instead of the hydroxyl substitutes (-OH) of the acid. Esters tend to have pleasant, fruity odors.
Isopleths acetate is known for its banana-like scent. Isopleths acetate is produced via Fischer Stratification from isopleths alcohol and acetic acid.
Fischer Stratification is carried out in a reflux set up which allows heating the reaction mixture at Its boiling temperature to form products without losing any of Its components. This was followed by distillation to Isolate isopleths acetate.
Next Is the addition of sodium carbonate to neutralize any acid which has been distilled which was later tested using litmus paper, washing with Ice water, washing with calcium chloride and Dalton of anhydrous calcium chloride. This was followed by another distillation process.
The result of the experiment is approximately pure isopleths acetate of probable yield. Introduction: This experiment focuses on the process of producing an ester, isopleths acetate. Learning the synthesis of isopleths acetate is important since isopleths acetate is used as flavors, fragrances and components of other commercial products in the industry. This experiment aims to synthesize an ester using the Fischer Stratification process which involves an alcohol and a carboxylic acid, in this case, isopleths alcohol and acetic acid respectively.
This experiment also Intends to calculate the % yield of the synthetic process. Experimental Details: The following apparatus were used in the experiment: Distilling flask Condenser Rubber tube Spring clip Iron stand Thermometer Bunsen burner Wire gauze Iron ring Separators funnel seekers Calibrated test tube Graduated cylinder Funnel Pipette separator Container (for finished product) rest Tube brush Ruler- Meyer flask Safety goggles rhea following materials were used in the experiment: Isopleths alcohol (at least 70. 2 ml) Acetic acid ( at least 28. 58 ml) 3 g concentrated sulfuric acid Neater (at least 11 ml) 2 g Sodium Carbonate 15 ml of ice water Two separate 10-ml portions of fresh 50% calcium chloride Granules of anhydrous calcium chloride Litmus paper Cotton Clay chips rhea following procedures were carried out in the experiment: a. In a 125 ml distilling flask, 0. 65 mol (70.
62 ml) of isopleths alcohol, 0. 50 mol (28. 58 ml) of acetic acid and 8 g of concentrated sulfuric acid were carefully mixed. B.
The flask was attached to a reflux condenser.
The side arm of the flask was closed with a short piece of rubber tube and spring clip. C. Clay chips were added.
D. Mixture was refluxed for 30 minutes. E. After reflux, the flask and condenser were arranged for distillation.
Distillation was carried out slowly, not exceeding 100 0 C. F. Ten drops of the distillate was collected and poured into about 1 ml of water. The odor was observed and noted. G. The distillation was continued until the entire ester product was collected.
H. Two grams of powdered sodium carbonate was added to neutralize the acid which has been distilled.
The flask was not corked while shaking the flask. I. Ten ml of water was added if a separate layer does not appear when the carbonate was added.
J. Carbonate was added until the ester was neutral to litmus. Afterwards, the ester was separated from the water layer. K.
The ester was washed with about 15 ml of ice Neater. Then, the water layer was rejected. L. It was mixed with two separate 10-ml portions of fresh 50% calcium chloride solution. The washings were discarded. M.
Rhea ester was transferred to a dry flask and was dried by adding anhydrous calcium chloride. N.
The flask was covered well with a cork and was reserved for the next Neater layer and unused calcium chloride and was filtered through cotton into a dry distilling flask. P. The mixture was distilled, allowing a 30 boiling range. Q.
The finished product was weighed and the % yield was calculated. Results and Discussion: Esters are derivatives of carboxylic acids in which the call carbon bears an alkyl group (-OR) rather than the hydroxyl group (-OH) of the Figure 1: General structure of ester and an example Most esters have pleasant, fruity odors and are widely used as fragrances, flavors and components of other commercial products.
Figure 2: Table of esters and their corresponding scents In this experiment, we synthesize amyl acetate which is known for its banana scent. Figure 3: Structure of Somali acetate Amyl acetate is produced via Fisher Stratification from an alcohol, isopleths alcohol and a carboxylic acid, acetic acid with an acid catalyst, preferably a strong acid like sulfuric acid.
The reaction proceeds by way of necrophilia substitution at the call carbon of the carboxylic acid. The reaction mechanism starts with the preparation of the call oxygen of the carboxylic acid, which is acetic acid.
The preparation activates the call carbon for necrophilia attack. Figure 5: Preparation in Fischer stratification Next is the necrophilia attack at the call carbon by the oxygen atom of the alcohol to form a tetrahedral intermediate. The alcohol in this case is isopleths alcohol.
Figure 6: Necrophilia attack in Fischer stratification Next is the proton transfer to the hydroxyl oxygen of the carbonyl group. This preparation converts the hydroxyl group into a good leaving group, water. Figure 7: Proton transfer in Fischer stratification Next is the loss of water forming the propionate ester.
Figure 8: Dehydration in Fischer And lastly is the proton transfer to a base, resulting in the formation of the ester.
Figure 9: Dehydrogenation in Fischer stratification Fischer stratification is an equilibrium reaction which tells us that the reaction mechanism is reversible. For the forward reaction to be favored, one of the reactants must be in excess, in this case, it was isopleths alcohol which was in excess and acetic acid was the limiting reactant. The experiment requires 0. 65 mol alcohol, 0. 50 mol acetic acid and 8 g of sulfuric acid.
From these given information we were able to compute for the needed volume for both acetic acid and isopleths alcohol, reaction.
This was done through following conversions and geochemistry: Illume used: Isopleths alcohol Illume used: Acetic acid Verifying the limiting reactant and the reactant in excess he amount with lesser number of moles is the limiting reactant while the one with the larger amount is in excess. This proves that acetic acid is the limiting reactant and isopleths alcohol is the one in excess. Theoretical yield: rhea theoretical yield of the experiment is 74. 2 ml of the ester, isopleths acetate.
Fischer stratification is conducted at reflux. The purpose of reflux is to heat a reaction mixture at its boiling temperature to form products, without losing any of the compounds in the reaction flask. In a reflux setup, a condenser is set vertically to the top of the reaction flask. Any compound that vaporizes will condense when it enters the cool environment of the reflux condenser and then will drain back into the reaction flask. Figure 10: Reflux setup increase the amount of ester product.
This was done at 100 0 C since the boiling point of water is at this point.
Since acetic acid has already been consumed and Neater has distilled off first because it has the lowest boiling point, what is left after distillation is the sixpenny acetate (149 0 C), unrelated isopleths alcohol (117 0 C) and the catalyst sulfuric acid (337 0 C). The catalyst affects only the rate of reaction, not the extent of the equilibrium reaction. Next is the addition of powdered sodium carbonate to neutralize the acid in the reaction mixture. The reason for adding sodium carbonate’s to remove the sulfuric acid by turning it into a salt, sodium sulfate.
HOSTS + Angina 0 Nassau H2O + CO The flask was not corked to allow carbon dioxide gas to escape.
A separate Neater layer forms because one of the by products is water and the salt migrates to the aqueous layer, leaving the organic layer( isopleths alcohol and isopleths acetate). Almost no more acid is present if the litmus test gives a neutral result, blue litmus paper remains blue and red litmus paper remains red. Afterwards, the water layer is rejected, leaving only isopleths alcohol and isopleths acetate.
Afterwards, the ester was washed with ice water which was done for two reasons: first, is to remove some acids which may not have not turned into salt when added with sodium carbonate.
Acids are water soluble and isopleths acetate and isopleths alcohol are not, thus, washing the mixture with water removed most of the acid. Second, some of the salts which were formed earlier upon addition of sodium reprobate may not be washed away, washing with ice water removes them further. Ice water was used because isopleths acetate may be soluble in hot water and slightly soluble in water at room temperature.
The ester may move to the aqueous layer and be washed away when the water layer is rejected resulting to a lower yield. Next is washing the ester with 50% calcium chloride solution. Calcium chloride is a drying agent which removes further traces of water.
These washings Newer discarded. Next, anhydrous calcium chloride was added which still removes Neater until the next laboratory period. The water layer and the hydrated calcium Chloride were decanted leaving only isopleths alcohol and isopleths acetate. To separate isopleths acetate and isopleths alcohol, distillation was done.
Isopleths alcohol (117 0 C) is distilled out first because it has a lower boiling point relative to isopleths acetate, separating both. From the distillation process, we are able to note the boiling point range: 146 0 C – 149 0 C.
The receiving flask weighed 118. 29 g and the mass of the receiving flask with the isopleths acetate was 136. 76. Therefore, the weight of the collected isopleths acetate is 18.
47 g. Calculating the % yield: loss of liquid by surface adsorption on the glassware especially firing distillation and mechanical loss( transfer of liquid from one container to another).
Conclusion: Therefore, isopleths acetate can be produced via Fischer stratification from acetic acid and isopleths alcohol with sulfuric acid as catalyst. Following the Fischer stratification process which was done in reflux, several extraction and purification processes were applied such as distillation to separate water from the reaction mixture, addition of sodium carbonate to transform sulfuric acid into sodium sulfate alt, making it Join the aqueous layer; washing with ice water to remove unwashed acid; washing with calcium chloride and anhydrous calcium chloride to remove water from the reaction mixture.
After the following extraction and purification processes, only isopleths alcohol and isopleths acetate is left in the mixture.
These two are separated via another distillation process due to differences in boiling points, Isopleths alcohol having a lower boiling point. The yield of the resulting ester product Nas lower than expected due to several reasons including surface adsorption of glassware and mechanical loss.
Supporting information: Aside from Fischer stratification, another way of producing an ester is by converting it directly from a carboxylic acid directly via SIN reaction of a carboxylic ion with a primary alkyl halide or by converting the carboxylic acid into an acid Chloride and then converting it into an ester.