Add deionized water to the volumetric flask to the 250ml mark on the volumetric flask. 13. Read the volume from the bottom of the meniscus. 14. Swirl the solution to ensure that the oxalic acid crystals are properly dissolved in the deionised water.
After the addition of nitrating mixture remove the flask from ice bath and allow to stand for 1 hour. Then transfer the reaction mixture in to 200 mL water containing a piece of crushed ice to get crude p-nitroacetanilide. Allow it to stand for 15 minutes ,filter on a Buchner funnel with suction ,wash with cold water and dry in an oven at 100 0C.o-nitroacetanilide is also formed together with p-isomer but being more soluble in water remains in the filtrate. Recrystallize a portion of crude product from rectified spirit when pale yellow crystals of pure p-nitroacetanilide are obtained. Mechanism: Reaction
32 100 μL of afore-prepared sample solution and the mixed reference standard were diluted 100 times with ethyl acetate. 50 μL of these dilution solutions were separated on the TLC plate coated with SNISG. The plate was developed with petroleum ether: ethyl acetate (4:1) and the movement of solvent was usually controlled at 1 cm from the upper edge. After completion, the plate was dried until no solvent smell remained. It was sprayed with an ethanol solution containing 10% sulfuric acid, and heated at an infra-red drier until obvious color came up, as shown in Fig.2 (B.ab).
A total of 30 g of seaweed Sargassum sp. washed and dried. The dried seaweed soaked in a solution of 0.4% formalin for 6 hours and 1% HCl solution for 1 hour and then washed with distilled water to pH neutral. Furthermore, seaweed cut added a solution of Na2CO32% with a ratio of 1:30 (w/v). Subsequently extracted by Microwave at power level 70 for 16 minutes and then filtered.
Firstly a 100 ml solution of AgNO3 (1mM) is prepared in a beaker. Then 10 ml of sodium borohydride (0.1M) is added drop wise to the beaker under continuous stirring for 6 hours. A change in the colour is observed and a solution of pale yellow is obtained. This mixture is allowed to rest for 8 hours before use. 2.3.2 Preparation of silver nanoparticles with citrate as capping agent Firstly a 10 ml solution of AgNO3 (0.01M) is prepared in a beaker.
Place the test tube of benzoic acid/lauric acid in the 60℃ water on the hot plate and when the solid solution begins to melt place the thermometer that was in the water into the test tube. Continue to heat the solution until it reaches about 55℃. Using the test tube holder, transfer the liquefied solution tube to the 25℃ water and record the temperature at 30-second intervals using a clock or stopwatch using a pencil until the solution reaches 35℃ or close to the temperature due to experimental error. While cooling, gently stir the solution using the thermometer until the solution begins to solidify. Once all the data is collected, reheat the solid solution tube in the warm water until it melts and remove the thermometer and wipe it off to avoid the solution adhering to the thermometer.
Preparation of Polyaniline Solution. To obtain polyaniline solution, prepare 0.12M aniline solution by adding 2 ml of aniline into 200 ml of 1 M sulfuric acid. Start with 98% purity sulfuric acid, 10.8784 ml of 98% sulfuric acid is added to 200 ml distilled water to obtain 1 M sulfuric acid. 0.12 M aniline solution can be created by adding 2 ml of aniline and 200 ml of 1 M sulfuric acid. Refrigerated the solution for a night to let the polyaniline solution form nanotube structure.
Now we place into the Erlenmeyer flask filled with Na2SO3 (aq), 30ml of 0.3 mol/L solution of HCl. 6. Right after mixing the two solutions, we quickly put the cap on the flask so that all of the gas produced is transferred through the glass tubes into the measuring cylinder. 7. After we see that the reaction is complete, we can read the measurements from the thermometer, pressure gauge and measuring cylinder to get the mass, temperature and pressure which we will need for later calculations.