Hydrolysis of an ester Essay
Hydrolysis of an ester
For the hydrolysis of methyl benzoate, care must be taken throughout the procedure as a number of dangerous substances are being used. During the procedure a labcoat, goggles, and gloves must be worn throughout. Specific safety instructions for chemicals or procedures are explained in the step that they are introduced. Observations, readings, and necessary safety precautions are discussed in the same order as the procedure was carried out in. 1. Safety: Methyl benzoate is harmful is inhaled or is it gets into contact with the skin or eyes or if swallowed.
So it is necessary to carry out the entire procedure in a well-ventilated area and gloves and goggles must be worn. Sodium hydroxide is a caustic soda and so is not very dangerous however regular safety precautions (goggles, labcoats and gloves) and care is still carried out to prevent spillages. Ethanol is highly flammable and dangerous substance as it contains methanol. Therefore, it should not come into direct contact with any flame. It is harmful it swallowed, inhaled or comes into contact with skin. Observations:
Methyl benzoate is originally a transparent liquid however the addition of the sodium hydroxide, ethanol and anti bumping granules turns the liquid cloudy. 2. Safety: As a Bunsen burner is being used a heat mat should be placed underneath and there should be careful control of the flame. Before heating the flask the condenser should be turned on to ensure that the liquid does not boil rapidly and shoot out through the other end of the condenser. Observations: The liquid turned from cloudy to clear upon heating. 3. Safety:
Hydrochloric acid is a corrosive substance but at 2mol dm-3 it is an irritant to the skin, so there must be extra care throughout to ensure that no spillages occur and goggles must be worn. Observations: Before the addition of methyl orange indicator the liquid was transparent and appeared to have an oily texture. The methyl orange indicator turned the liquid bright orange, and then with the addition of hydrochloric acid the solution turned a bright pink colour. After filtering the solution, a light/pale pink precipitate was formed.
Readings: The mass of the solution before addition of the acid was 22.1g (solution only-excluding conical flask mass.) 20cm3 of acid was required to turn the solution completely pink, increasing the mass of the solution to 31. 81g. 4. Safety: As boiling water is being used care must be used to ensure that it is not spilt accidentally. Observations: After the addition of boiling water the light/pale pink precipitate slowly crystallised into transparent crystals that were settled at the bottom of the flask in which pink liquid had formed. After allowing the crystals to dry on filter paper, they had turned white from transparent.
Readings: The precipitate obtained weighed 8. 11g and required 50cm3 of boiling water to crystallise. 5. Safety: To determine the melting point of the sample an aluminium block, Bunsen burner and thermometer are used. As the objects are being heated and are very hot they should be not touched and should be allowed to cool after. Observations: The samples melted into a white liquid, which evaporated upon more heating. Reading: The samples placed on the aluminium block begun to melt at 119oC and had completely melted when the temperature was122oC.
University/College: University of California
Type of paper: Thesis/Dissertation Chapter
Date: 6 July 2017
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