Moreover, it acts as dehydrating agent, forcing the equilibrium to the products and lead to a greater yield of ester. After the addition of trace amount of concentrated sulfuric acid, the reactant flask is heated so that the reaction can be speeded up and ester can be obtained faster. The reason of adding concentrated drops-by-drops into the reactant flask and swirl the flask while adding the acid is to prevent any part of the mixture getting too hot and reacting to form unwanted darkly coloured by-product. Before the heating of the liquid, boiling chips is added inside the reactant flask to allow a nucleation site for gradual boiling and avoid a sudden boiling surge where may cause the liquids inside the reactant flask to overflow or spill out as it has
Saponification is important to the industrial user for it helps to know the amount of free fatty acid that is present in a food material. The quantity of free fatty acid can be distinguished by determining the quantity of alkali that must be added to the fat or oil to make it neutral. This test is done by warming a known amount of oil or fat with alcoholic KOH, which will convert the free fatty acid into soap. This soap is removed and the amount of fat remaining is then determined by subtracting the amount of obtained soap from the amount of fat originally taken before the test. The saponification number or “sap” measures the present bonded or unbonded acids in oil or fats.
Analytical indices related to fats and oils can be distinguished as structure or quality indices. Structure indices are the iodine value (IV), a measure of total unsaturation of an oil or fat; the saponification value (SV), an indicator of average M.W. ; and the hydroxyl value (HV), which is applicable to fatty compounds (or their mixtures) containing (Knothe, 2002). Saponification is the hydrolysis of fats or oils under basic conditions to afford glycerol and the salt of the corresponding fatty acid (Chalmers and Bathe, 1978). The saponification number is the number of milligrams of potassium hydroxide required to neutralize the fatty acids resulting from the complete hydrolysis of 1g of fat.
Throughout the mixing process, the clear red solution slowly changes to a denser red solution (Appendix figure 23). A thermometer was used for temperature checking. The beaker was removed from the hot plate when the temperature was found to be higher than 50 ℃. This was done to prevent a sudden gelation happen before all the active dissolved in the ethylene glycol. Moderate heating of the solution for a period of time is allowed to obtain a wet gel (Appendix figure 24).
Purification of brine The first step in the Solvay process is brine purification. This step is done to produce a pure sodium chloride solution. Brine contains impurities namely calcium and magnesium salts. Sulfates also can be found in some brines. These impurities have to be eliminated because they will produce unwanted insoluble salts by reacting with alkali and carbon dioxide, thus affecting the quality of the soda ash.
Ensure that solid is completely dissolved using a stirring rod. Next, a 10 mL beaker is filled with 3 mL of HCl and measure 10 mL of ionized water into a 140 mL beaker. Carefully turn on laboratory burner and start cleaning the Nichrome wire by dipping it into concentrated HCl acid. Hold the Nichrome wire on top of the flame and repeat the step until the wire doesn 't show any color. When the wire is clean, dip the wire again with some of the acid and dip it into the solution with the unknown compound in it.
Observations Step Observation Adding sulfuric acid into the alcohol and carboxylic acid solution Surface of the round bottom flask is warm Poring the ester solution in the bottle after reflux Dense gas can be seen Washing the ester with distilled water The ester layer is immiscible with distilled water. Washing the ester with sodium carbonate solution Effervescence -bubbles of gas produced -a ‘pop’ sound could be heard when the separating funnel is closed and opened again. The ester layer is immiscible with the sodium carbonate solution Adding anhydrous calcium chloride into the ester solution Heat would be produced as the surface of the conical flask feels warm. Anhydrous calcium chloride crystals would clump up after swirling. Distillation of ester solution after the washings At first the solution slowly condenses out but as the temperature increases, the solution condenses very fast.
3.5 SOLVENT EXTRACTION PROCESS First, 10g of the RSS were transferred into a thimble. At the same time, 150mL of solvent was poured into the round bottomed flask. Then, Soxhlet were heated using heating mantle. The oil was recovered from the solvent by evaporation of the solvent in a rotary vacuum evaporator under reduced pressure. The mixture of the oil and excess solvent was poured into a weighed round bottomed flask.
Stage 1: Sampling The samples are cycled over the MEPS Barrel insert and needle (BINS) so as to transfer the interested compound into the sorbent. Stage 2: Washing 20 µL to 50 µL of washing fluids are cycling over the BINS in order to withdrawn the non-specific binding compounds. Stage 3: Elution The interested compounds are desorbed by introducing the elution solvent into the BINS. Stage 4: Injection Finally, the samples are injected into the liquid or gas chromatograpy. Advantages of MEPS 1) Little amount of sample volumes is required up to 10
During physical exercises, muscles may produce lactic acid if the work is intensive. The lactic acid thereafter donates a hydrogen ion to the water in the blood to create hydronium. As the system is at inbalance,the equation will be shifted to the left do decrease the concentration of hydronium. Furthermore, if one has an excess of carbon dioxide in the blood, more hydrogen ions will be produced and an increased concentration of hydrogen ions will cause the pH to lower, a change in pH will have to occur. With taking Le Chatelier’s Principle in consideration, “the position of the equilibrium of a system changes to minimise the effect of any imposed change in conditions”.