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Synthesising organic and biochemical compounds - Preparation of Ethanol and Ethanoic Acid.

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� Unit 5: Synthesising organic and biochemical compounds Assignment 1 Preparation of Ethanol and Ethanoic Acid Prepared by: Tahir Sheikh-Noor Content TOC \O "1-3" \H \Z | HYPERLINK \L "_TOC58921020" INTRODUCTION (SECTION1) PAGEREF _TOC58921020 \H 2 HYPERLINK \L "_TOC58921021" INTRODUCTION TO REPORT PAGEREF _TOC58921021 \H 2 HYPERLINK \l "_Toc58921022" Practical one Equation PAGEREF _Toc58921022 \h 3 HYPERLINK \l "_Toc58921023" Practical three Equation PAGEREF _Tc58921023 \h |4 SECTION2 INTRODUCTION 4 ISOMERISM 4 STARCH & CELLULOSE STRUCTURE 6 OPTICAL ISOMERISM 7 INTRODUCTION (SECTION3) 9 CATALYTIC ACTION 9 CATALYST 10 ACTIVATION ENERGY 11 ENZYMES 12 The lock and key theory 14 ENZYMES: STRUCTURE AND FUNCTION 16 INTRODUCTION (SECTION4) BANNER 16 BIOTECHNOLOGY 16 DIFFERENTIATES BETWEEN TRADITIONAL AND MODERN BIOTECHNOLOGY 17 ENZYME TECHNOLOGY+19 METHOD 19 COMPARISON WITH INDUSTRIAL PROCESSES 20 Introduction (Section1) Introduction to report This report contains 5 practical experiments to produce ethanoic acid from ethanol. The first practical is the preparation of ethanol from glucose using yeast during the process of fermentation; this has been demonstrated in class. In this practical the glucose is converted into ethanol and carbon dioxide by respiratory enzymes from the yeast. The ethanol solution will be between 5-15% and the ethanol will be separated from the yeast by filtering. Then the ethanol will be divided. In the second experiment we are going to distillate ethanol solution, which involve measuring both the volume and the mass of the ethanol solution, we can work out the density from the volume and mass. We will then compare the density of the solution with that of pure water and pure ethanol; it is possible to calculate the percentage concentration of the solution. The third practical will be oxidising ethanol to ethanoic acid, in this experiment we will start with 96% ethanol. We can achieve a successful oxidation by boiling gently under reflux with acidified sodium dichromate. The fourth practical is to distillate ethanoic acid solution; this is the continuation of the third practical and involves distilling the mixture to obtain a reasonably pure sample of ethanoic acid. ...read more.


See the diagrams below on substrates and enzymes. Within the normal range, changes in temperature of substrate and enzyme affect the rate of reaction in accordance with predictable relations between enzyme and substrate molecules. The effects of temperature may be explained on the basis of kinetic theory - increased temperature increases the speed of molecular movement and thus the chances of molecular collisions. Enzymes have an optimum temperature for their action. Above normal temperatures say 60 �C, heat alters permanently the enzyme molecule. This denature is caused by heat. This change - especially in the region of the active site - mean that the enzyme is inactivated, even when returned to normal temperature. It would be wrong to say that an enzyme is KILLED by heat, since it is only a molecule, not an organism. The higher the temperature to which the enzyme is given and the longer the heating is continued, the more it becomes denatured and becomes less efficient. Below normal temperatures, enzymes become less active, due to reductions in speed of molecular movement, but this is reversible, so enzymes work effectively when returned to normal temperature. The lock and key theory The lock and key theory is simply a way of describing how specific an enzyme is for its substrate. Just like a lock requires a specifically shaped key for it to work so does an enzyme. Each enzyme is a protein which is a polypeptide chain folded into a complex 3 dimensional structure. Part of that structure contains the active site, which is where the enzyme can bind to the substrate on which it will perform some chemical reaction. Because each enzyme performs a specific task on a specific substrate the active centre of the enzyme can be considered to be the "lock" which requires the specific "key" or substrate to perform the function. (see below for diagram on the key and lock analogy) ...read more.


Practical 5: Evaluation In this section evaluate data; in particular consider its reliability. Must include the following to achieve the criteria: * Comparison of results with published data (c3) * Discussion of the accuracy and reliability of the various methods used for checking purity; do this by considering errors and comparing the results with partner and with the published data (A2) * Discussion of the accuracy of the percentage yield determination (A2) Comparison with industrial processes Romford Brewery is a very large company with 600 personal; they make 250 million pounds from beer each year. They replaced their old manual system by a high tech computerised automation system. The automation made the production of beer very easy and quicker because the computers controlled everything that would normally done by hand, like the mashing process is monitored by computer which controls the temperature; the adding of the hobs which once again are computer controlled so that the beer has the right bitter favour and checked the temperature was right before adding of the hobs; the fermentation process is Romford produces 750 thousand barrels of beer a year, a barrel is equivalent 288 pints, and works out 1250 barrels per employee. All the beer made is supplied to 100s of pubs. Advantages of automation * Made the process more efficient. * Saved more money and time in the long run. * Reduced labours costs by employing less personal. * Allows them to produce economy of scale: a continuous. process same as mass production which is cheaper than batch production that Ridley use. * Heat exchanges save them money because the heat produce from fermentation can be used for another process. Disadvantages of automation * The automation cost 13 1/2 million * Romford has to still employ a lot of personal * The system will consume large a amount electricity Comparison of practical one with brewing The starting material 2 Tahir Sheikh-Noor AVCE Science 28/10/03 ...read more.

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