10- Transfer the ester layer to a small dry test tube and dry the ester with anhydrous CaCl2 and stir for 10 min. 11- put it in a preweighed dry round bottom flask . 14- Determine the yield, refractive index, and % yield of ester. Conditions :- 1) This reaction is catalyzed by acid, Like Fischer esterification. 2) Usage of water in step (5):So that after Estrification is completed , any excess unreacted acetic anhydride is hydrolyzed.
Use the wash bottle with deionised water to transfer all the oxalic acid crystals from the glass beaker to the funnel. 11. Rinse out all the oxalic acid crystals with the wash bottle from the funnel in the volumetric flask. 12. Add deionized water to the volumetric flask to the 250ml mark on the volumetric flask.
In the round-bottom flask (100 mL), we placed p-aminobenzoic acid (1.2 g) and ethanol (12 mL). We swirled the mixture until the solid dissolved completely. We used Pasteur pipet to add concentrated sulfuric acid (1.0 mL) to the flask. We added boiling stone and assembled the reflux. Then, we did reflux for 75 minutes.
The mixture was finally made upto 5 mL with distilled water and placed in hot water bath at 95ºC for 1 h. After cooling, 1 mL of distilled water and 5 mL of the mixture of n-butanol and pyridine (15:1, v/v) was added. The mixture was vortexed and after centrifugation at 4000 rpm for 10 minutes, the absorbance of the organic layer (upper layer) was measured in UV-Vis spectrophotometer (Shimatzu) at 532 nm against blank using distilled water. TBA when allowed to react with MDA aerobically formed a colored complex [MDA-(TBA) 2 complex] which was measured with spectrophotometer. MDA concentration (measured as TBARS) was calculated as
4) Use a 25 cm3 graduated cylinder for the initial measurements of each solution. Pour 20 cm3 of 0.5M FeCl3 and 20 cm3 of 0.5M KSCN in separate graduated cylinders. 5) Using a 10 cm3 graduated cylinder, pour the necessary volume of distilled water, in this case 5 cm3. After pouring the distilled water to the graduated cylinder containing the FeCl3. 6) Next, prepare a 50 cm3 beaker, and pour both reactants into it.
1 ml = 1 µg CN (x) Chloramine –T: Dissolve 1 gm chloramine – T in 100 ml distilled water. Prepare fresh solution daily. (xi) Pyridine (xii) 1-phenyl–3-methyl– 5-pyrazolone solution: Prepare a saturated aqueous solution (approximately 0.5 gm / 100 ml) by adding the pyrazolone to water at 75 0 C. Agitate occasionally as the solution cools to room temperature. (xiii) Bis–Pyrazolone (3,3-dimethyl-1-diphenyl) (4,4’-bis-2-pyrazolone)-(5,5’
To this, 80ml of cold water and 15ml of 2M HCl was added to the conical flask. Afterwards, 0.1ml of ferroin solution (as an indicator) was added. Next, titration was performed. The contents in the conical flask was titrated with 0.1M ammonia cerium (IV) sulphate until a yellow solution was produced. The experiment was then repeated without sample B (only the H2SO4 and water in the proportion 3:7, 6ml acid 14ml
This will make the limestone lose the carbon dioxide and increase the purity of the calcium carbonate. Secondly, filter this mixture to remove the remaining silica and other insoluble materials. Next, add oxalic acid (H2C204), to the limestone powered. This mixture will create a calcium oxalate ( CaC2O4), and aqueous carbonic acid ( H2C03), according to this formula: CaC03 + H2C2O4 -> CaC2O4 + H2CO3. The next step is to rinse the calcium oxalate and sprinkle some deionized water and pour it into a beaker.
Experimental Methods: 1. SYNTHESIS OF 4-BENZOYL BUTYRIC ACID METHYL ESTER Materials required * 5 oxopentanoic acid : 2 gm (Aldrich) * Methanol : 50 ml * Acetic Acid (Rankem) Procedure: * 2 grams of 5 oxopentanoic acid was weighed and placed in a round bottom flask and then to it 50 ml of methanol was added. It was placed on a hot plate and the temperature was increased to 50 degrees under ambient air conditions. * To the RB, 2 ml of acetic acid was added and then by attaching a condenser the entire reaction was put on refluxing at 70 degrees Celsius in an oil bath. * For work up: * The reaction media was concentrated till about 10 ml and then dry silica gel was added.
MATERIALS AND METHODS Bacterial strains and culture conditions Two S. aureus strains were used in the present study; S. aureus 8325-4 (SigB-) and SH1000 representing a SigB+.strain. Overnight cultures were grown in Luria Broth (LB) at 37°Cwith shaking at 150 rpm. Exposure to antibiotics was carried out as detailed below. Antibiotics Ciprofloxacin were purchased from Sigma-Aldrich CO. 10 mg/ml stock solution of antibiotic were prepared freshly with 0.1N HCl and stored at -20°C. During the experiment we diluted with sterile water 1:10 and 1:100 depending on the different drug concentration.