Quantity determination of Recorcinol compound by the Reaction with Ferric nitrate dissolved in nitric acid …………

By this paper we development of an analytical method to determine Recorcinol compound by coupling reaction for diazotized solution of Ferric nitrate dissolved in nitric acid in the presence of buffer solution Na2HPO 4 (PH= 10.8) to give a compound with a single azo dye salt having orange color soluble in water with high absortivity at a wave length 449 nm , an early study to have a perfect optimum condition was made for the determination. A calibration curve for a range of concentration (5-75)pm was taken and the value of molar absortivity was 1.5*10 3 L.mol -1 .cm -1 with a relative standard divation more than 1.26% and a recovery 98.77% . Also as we study the nature of the azo dye by mole fraction method, from the practical value we found that the mole fraction of the dye compound is 1:1(Recorcinol: Ferric nitrate dissolved in nitric acid) and the stability factor reach to 1.4*10 6 L.mol -1 .

absorbance at 425 nm. As there is a colorful method to determine phenols in drink water (4) which depend on the reaction of nitric acid with phenol to give nitrophenol , the last compound couples with phenol to give a colourred product. This method have a specific properties as its easy and fast also can be applicable in a substiuted phenol in p-position there for we can determine some of the pharmaceutical cosmetics which have a substuted phenols. An idometric method (5) was used for the determination also the optical phosphrylation and cerimetry method by dissolving the samples in ethanol and after acidation of the solution we added aditional of serem quntary solution (6) then we measure the external volume by titrating with sodium thio sulfate, this method have a high recovery also there is another method like ion-exchange, atomic adsorption and oxidation reaction with potassium dichromate compound (7) .There is another way to determine the phenol which depends on the appearance of colour, when phenol react with phosphat buffer solution with PH=4.5 after that we filter the solution to measure the intense of the final solution at a wave length 450 nm it will give a good recovery (7) Zhang develop a method for the determination which depends (8) on the reaction of phenol with 15% of potassium bromid solution (9) with little drops of sulfuric acid then the final compound which is succinimide titrate, the error percentage was less than 0.87 (10) . The science Norman shane developed an absorbance method to determine phenol depending on preparing of an extract then dilute it with standard amount of water then we measure the absorbance of the final solution to know the intensity of absorbance at a specific wave length and the resulting error was less than 0.82 (11) .
There is a an ion-exchang method which is used in some drugs compound (12) , after we extract phenol with dichloroforme then pass the product through an ion-exchanger also an oxidition method was used (13) by using dichromate solution and a catalysts with noticing the intensity of absorbance of the final solution , error percentage was less than 0.75.and nuclear magnetic resonance method was used to determine the phenol (14) .And the thin layer chromatography method was used by using silica jel product and the percentage error was less than 0.81.
Choir developed a determination method which depend on the analysis by using a high performance liquid chromatography method by taking a sample that we want to determine phenol (15) and mixe it with phosphoric acid separate it by using a centrifuge , this method was succeful and the error percentage was less th an (0.61) also a gel filtration was used to separate some of the drugs compound with Which prepare by weighting the compound from (BDH ANALAR) then dissolve it in 40 ml of distilled water, then heat the solution to increase the solubility then added 4 ml of 0.7 standard hydrochloric acid with cooling to zero degree by using an ice bath then added 0.0077 gm sodium nitrate with mixing. After 5 minute pour the dizonium final solution to 250 ml volumetric flask, and complete the volume by using cooling distil water to (4c) and keep the solution in the freezer. The final solution will be stable after 1 hr in room temperature which is (22 ). -hydrochloric acid (0.7 ) from (FLUKA A.G company).
We preper it with an approximate concentration by dilution of concentrated hydrochloric acid then titrate it with standard sodium carbonate to fix the concentration to (0.7 ). -sodium carbonate Na 2 CO 3 (0.7 ) from (BDH company) By dried sodium carbonate for an hour in (115 ) in watch glass then cool it and wieght 3.32449 gm from it then we dissolve it in distl water and complete to the final volume which is 250 ml in volumetric flask.
-solution 8 of sodium hydroxide (from Fluka A.G company) Prepared from standard amonia solution, to determine the exact molarity for amonia we prepare 8 of NH 4  10 ml 2 ml -to prepare phosphate buffer solution with PH=11.6 take 70 ml of (0.3 )of Na 2 HPO 4 solution and added to it 5.5 ml of (0.2 ) sodium hydroxid solution then dilute to 250ml by using distle water. C. experimental method 1. Determination of phenol by coupling reaction T he coupling operation done by using (500 ppm) of Recorcinol with (1000 ppm) of Ferric nitrate dissolved in nitric acid in present of phosphate buffer solution (PH=10.80) as we added 3ml of diazotized compound to 6ml of buffer solution then added different volume of phenol then added to it 500ml distle water after that measure the absortivity (A) for this solution against the blank solution at a wave length 449nm, as we draw calibration curve between the absorbance and the concentration we have a straight line.

Result and discussion: Primary test
We notice that in mixing of Ferric nitrate dissolved in nitric acid compound with phenol in basic media, a single azo dye with orange colour soluble in water formed, the reaction involve two step which is : a. Ferric nitrate dissolved in nitric acid compound react in acidic media in 0 with equal amount of sodium nitrate to give diazonium salt. b.when added phenol to the diazotizing compound in basic media a single azo dye with orange colour formed which give a high absortivity at a wave length 499nm.

The effect of PH
To reach to the optimum condition (high sensitivity, fast reaction and low absorbance) for the blank solution a study of Recorcinol with diazotizing compound 4-aminacet phenone in neutral, acidic and basic media was mad as we notice that no azo dye is formed in neutral and acidic media and the best media for the coupling reaction is the basic media which PH=10.80 as table (3)   The effect of the buffer solution on the intensity of absorbance After fixing the optimum condition for the reaction. an experiment was make to give the perfect volume for the buffer solution which give a high sensitivity as table (5) which shows that 4ml is the perfect volume of the buffer solution which give a high sensitivity as table (5).  As we consider I as number one because it a high sensitivity 6. Study the colour stability for the formed complex from the reaction An experiment to explain the stability of the colour of the complex formed due to the reaction between the Recorcinol and Ferric nitrate dissolved in nitric acid compound in present of phosphate buffer with optimum condition as shown in table (8) the stability time for the colour of the complex is hr  (1) show the standard curve. Figure (1

) the titration curve of Recorcinol
8. study of accuracy and compatibility of method A study for the accuracy and compatibility for the method was mad as we take a different concentration of Recorcinol (80-25-5)ppm by using an optimum condition, the table (9) represent the result.