3. Results and discussion 4-Chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) is an activated aryl halide that has been used as a chromogenic and fluorogenic reagent for the determination of many drugs with primary and secondary amino groups [22-24]. The reaction of NBD-Cl with LBT has not been investigated yet. LBT contain secondary amino group which can react with NBD-Cl in alkaline medium to form a yellowish green colored product. This derivative exhibited maximum fluorescence intensity at 540 nm after excitation at 476 nm (Figure 2), the maximum absorbance of the reaction product was measured at 480 nm (Figure 3). 3.1. Optimization of the reaction conditions The experimental parameters affecting the development and stability of the reaction product between the drug and the reagent were investigated and optimized. Each parameter was changed individually while the others were kept constant. These parameters include; pH, buffer (type & volume), concentration of NBD-Cl, reaction and stability time, temperature, acidification and diluting solvent. 3.1.1. Effect of pH The effect of the solution pH on the reaction product formation was studied in the pH range of 6.5– 9.5 using Clark …show more content…
Equimolar solutions of both the drug and NBD-Cl reagent (1×10-3 M) and (1×10-2 M) were prepared for method I and method II respectively. Then portions of mixture of master solutions of the drug and reagent were mixed comprising different complementary proportions. Either the relative fluorescence intensity or the absorbance were measured. A blank experiment was carried out simultaneously. The stoichiometry between the drug and NBD-Cl reagent by both methods as shown in Figure 8, it is clear that the ratio is 1:1. Based on this ratio the suggested mechanism of the condensation reaction with NBD-Cl was presented in Scheme
The reaction was repeated 3 times and average rate noted. From these rates a graph was plotted which describes the relationship of the pressure produced and number of drops added. The reaction rates were measured by Kpa/min and were written to 4 figures for precise results. Time was measured by stop watch. Table 4 shows a summary of all the groups which participated in the lab session.
The test tube was quickly inverted once or twice and then poured into the cuvette and placed into the calorimeter. The absorbency readings were recorded every fifteen seconds for about five minutes, or until the reaction was complete. The same steps were followed for each of the test tubes. We then calculated the initial reaction velocity for each of the different pHs using the following equation (absorbency as y and time as
A: The compound that is being oxidized in the luminol synthesis reaction is Na2S2O4, (Sodium Hydrosulfite. Since sodium hydrosulfite is acting as the reducing agent, in this experiment. 2. What is the purpose of acetic acid in the luminol synthesis reaction? How would the amount of the luminol product obtained at the end of the reaction be affected if the number of moles of NaOH added at the beginning of the reaction and the acetic acid added at the end of the reaction added were reversed?
In addition, phenolphthalein was added as an indicator. The aliquots were titrated against sodium hydroxide (NaOH) solution until end point was reached, after which volume of NaOH consumed was recorded. The value of the rate constant, k, obtained was 0.0002 s-1. The experiment was then repeated with 40/60 V/V isopropanol/water mixture and a larger value of k = 0.0007 s-1 was obtained. We concluded that the rate of hydrolysis of (CH3)3CCl is directly proportional to water content in the solvent mixture.
In a two-day experiment, an SN2 reaction was conducted and benzyl bromide, sodium hydroxide, and an unknown were used. In a nucleophilic substitution reaction, the nucleophile and the alkyl carbon determine if the reaction is an SN2 or SN1 reaction. In an SN2 reaction, the process occurs in one step and works best with a primary carbon along with a strong nucleophile. During the experiment, recrystallization was used to purified the product; meanwhile, the melting point range and thin layer chromatography (TLC) data were used to identify the product of the reaction. After the completion, the unknown chemical was determined as 4-chlorobenzyl phenyl ether.
A spin vane was added and a water-jacked condenser was attached. Isopentyl nitrite (0.06ml, 0.045 mmol) was dissolved in 1,2-dimethoxyethane (0.50 ml) in a 3-ml conical vial and caped to prevent loss by evaporation. Running the reaction. The mixture in the 5-ml conical vial containing the tetraphenylcyclopentadienone and anthranilic acid was heated on an aluminum block to 140° C. Once the mixture started to boil the prepared mixture of isopentyl nitrite was added to the 5-ml conical vial through the top of the condenser using a pasture pipette.
Lecturer Date Introduction Theoretical Background Procedure The procedure was segmented into two categories, the reaction set up and the crude product isolation. Reaction set up The magnetic stirrer was prepared through placing it in the fume cupboard. 1 mmol of L-Phenylalanine was placed and weighed in a 5 mL conical vial.
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 purpose of this experiment is to perform a two step reductive amination using o-vanillin with p-toluidine to synthesize an imine derivative. In this experiment, 0.386 g of o-vanillin and 0.276 g of p-toluidine were mixed into an Erlenmeyer flask. The o-vanillin turned from a green powder to orange layer as it mixed with p-toludine, which was originally a white solid. Ethanol was added as a solvent for this reaction. Sodium borohydride was added in slow portion as the reducing agent, dissolving the precipitate into a yellowish lime solution.
Nevertheless, the latter is not used in this experiment since it is very reactive and extremely flammable. On the contrary, NaBH4 is relatively mild and it can be used with protic solvents. In this manner, 1.507 grs of the ketone 9-fluorenone were mixed with 30.0 ml of 95% ethanol in a 125 ml Erlenmeyer flask. The bright yellow mixture was stirred during 7 minutes until all the components were dissolved.
Stoichiometry The stoichiometry for oxidation of p-Aminobenzhydrazide / p-Chlorobenzhydrazide by Fe(III) in the presence of PPDTS have been studied. A known excess of Fe(III) was added to a solution containing known amounts of p-Aminobenzhydrazide / p-Chlorobenzhydrazide and PPDTS. The reaction was allowed to go to completion, which is indicated by the constancy of absorbance of the reaction mixture.
The objective of this experiment was to use an aldol condensation reaction to synthesize 3-nitrochalcone from 3- nitrobenzaldehyde. This was accomplished with a Diels-Alder reaction that utilized 3-nitrobenzaldehyde, acetophenone, ethanol, and sodium hydroxide. The mechanism for the synthesis of 3-nitrochalcone is presented in Figures 1 and 2. The alpha carbon on the acetophenone is deprotonated. This is followed by the attack of the alpha carbon anion on the carbonyl carbon on the 3-nitrobenzaldehyde.
They function by binding to the enzyme-substrate complex and are used to make drugs. There are reversible and irreversible inhibitors. The three types of reversible inhibitors include competitive, noncompetitive and uncompetitive. The type of inhibitor can be identified by the reaction Vmax, Km and Ki. In this experiment, the inhibitor used was 75 mM phenylalanine.
1.1Liquisolid Systems Technology Many recently developed drugs are poorly water soluble compounds, which cause difficulties in the development of solid dosage forms with good bioavailability(1). The therapeutic effect of the drug is reliant on the bioavailability which in turn relies on the solubility and dissolution rate of the drug, therefore; solubility is the most important factor to get the required concentration of drug in the systemic circulation for therapeutic response to be attained(2). For different poorly soluble medications, bioavailability is limit via the dissolution rate.
Introduction The goal of the experiment is to examine how the rate of reaction between Hydrochloric acid and Sodium thiosulphate is affected by altering the concentrations. The concentration of Sodium thiosulfate will be altered by adding deionised water and decreasing the amount of Sodium thiosulphate. Once the Sodium thiosulphate has been tested several times. The effect of concentration on the rate of reaction can be examined in this experiment.