Oxidising Ethanol TO Ethanal PDF

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NAME: SANNAH HANIF

UNIT 22

GROUP: NDS1D

OXIDISING ETHANOL TO ETHANAL

RISK ASSESSMENT/ HEALTH AND SAFETY:

When doing any experiment, it is very important to ensure that a lab coat is worn. This is because it is a piece of clothing that protects the body in case of a spillage of a liquid that is hazardous or if there is an accident. Making an aldehyde, there’s a lot of apparatus that could be hot, which means there is a higher chance of dropping the glassware and spilling the liquid, the lab coat therefore protects the body from being harmed. Before starting the experiment, you should make sure that you are wearing protective eyewear, for example goggles, this is because similar to a lab coat, the goggles are also used as a protective shield which protects anything going into the eyes. When liquids are being heated or boiled, there can be a lot of spillages therefore wearing goggles ensures that nothing goes into the eyes. Another protective piece of clothing is gloves, this covers the hands and makes sure that when dealing with a toxic substance that nothing will harm the hands, as if the hands were not covered and you spilt concentrated sulfuric acid on your hand, that would be very dangerous as it is a corrosive acid. When handling ethanol into ethanal, a heating mantle is more useful and more appropriate to use than a Bunsen burner, flammable substances are easier to experiment using a heating mantle which prevents a fire, a Bunsen burner compared to a heating mantle is very different because the heating mantle is able to change the temperature and is more secure rather than a Bunsen burner that could cause a fire. To avoid getting fumes, a water bath can be used to cool down. Due to the position of the apparatus when connected together, it can be easier to grease the equipment, which allows the equipment to come apart quickly and easily at the end of the experiment. When wanting to weigh the sodium dichromate, make sure that the right amount is weighed. If the weighing is done inaccurately then this could make the apparatus hot a lot, which can lead to breakage of glass, and can be very dangerous.

The functional group that is reacting is an alcohol. The functional group that has been formed is an aldehyde, the type of reaction is distillation. The reason why the sulphuric acid was added slowly is because to ensure that the temperature didn’t rise up so frantically and that drop by drop the temperature should gradually rise up. If the temperature rises up quickly, then this could result in shattering of the glassware as the glassware would be really hot, this is why the flask is kept in a ice bath in order to cool down and avoid breakages.

NAME: SANNAH HANIF

UNIT 22

GROUP: NDS1D

Also because of the fact that we were trying to make an aldehyde, the distillation was set up so that the aldehyde wouldn’t oxidise further with the acidified potassium dichromate and the distillation method helps to extract and remove the aldehyde once its produced.

http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel_pre_2011/oneearth/fuelsrev1.sht ml a carboxylic acid is produced by oxidising the alcohol in order to make an aldehyde. The aldehyde is then oxidised further to form a carboxylic acid. To get the aldehyde to return back into the reaction flask, a reflux will need to be set up to allow this to happen, this will then let the aldehyde be oxidised to the carboxylic acid. Its important to dissolve it using distilled water because the solid might get stuck or left in the beaker and therefore by using a pure substance such as water it allows the remaining solid to be swirled up in the water and be put in the flask. If solid is left behind, this could affect the whole experiment, because the aldehyde has a low boiling part it could turn into a gas, ice is used in order to make sure the aldehyde isn’t evaporated away and remains a liquid. Mass = 8 x 0.79 = 6.32g 6.32/Mr 6.23/46.07=0.137mol 0.137 x 44.05 = 6.03 Expected yield – 6.03 % yield = actual /theoretical x 100 Actual = 6.6 x 0.78 = 5.148

NAME: SANNAH HANIF

UNIT 22

GROUP: NDS1D

Theoretical = 6.03 % yield = 5.148/6.03 x 100 = 85.37% Atom economy = desired product/all products 44.05/62.05 = 0.71 x 100 = 71% The refractive index of my sample is 0.74 The purity of my sample is not very pure but a bit pure as the reactive index of a clear solution would be 0.85. One factor that could affect the purity of the sample is filtering, this is due to the fact that not all of the sample is obtained, a bit can be left behind. A clear and thorough analysis of this cannot be made as he complete sample is not present. A second factor would be the equipment and starting materials, this is due to the fact that there could be contaminated equipment or dirty starting materials which could affect the whole experiment. An example of impure factors could be deionised water for example. If the starting materials are contaminated then the end product will also be contaminated. A change to the method would have to be to have more substance because ethne this would allow us to have a fair amount of product that is made at the end. More of the desired would be a massive change. This would increase the purity of the sample, as well as the atom economy which means that the percentage yield would be high too. Another change to the method is using less equipment as possible, this could prevent breakages and spillages. For example, using a funnel and pouring the solution into the funnel. Less equipment would mean less contamination of the equipment so the purity would increase and there would be less of the substance and more solution would successfully be moved. Therefore, having more sample and an increase in purity. The final change would be ensuring that the equipment is sterilized and contamination free. This can be done by asking the technician before hand whether the equipment is clean and if the sample is less contaminated then there will be an increase in purity. Difficulty Step 3 products need to be mixed well

Transferring substances

Maintain the temp in an ice bath

Why it affects purity and yield This will affect the yield and purity because if the products are not mixed together then the reactions won’t be clear or side reactions could occur. Some products can be left behind when transferring the proper reactions cannot take place as there could be contaminated apparatus causing cross contamination. If temp goes too high, the aldehyde could turn into vapour and could lose the percentage yield or could

Improvements To improve this, we could use a magnetic stirrer to make sure that the products are properly mixed.

To get rid of cross contamination, the apparatus should be washed out before the experiment is carried out.

Make sure it is observed carefully so ensure the temperature isn’t boiling.

NAME: SANNAH HANIF

Liquid from a separating funnel added at some rate as the liquid is distilled

UNIT 22 become flammable. If we didn’t do this, a carboxylic acid would be formed and not an aldehyde which we don’t want.

GROUP: NDS1D

Ensure we are adding the liquid at the same rate each time and really focus and concentrate when ding this....