1.0 ABSTRACT This main objectives of this experiment are to carry out a saponification reaction between NaOH and Et(Ac) in CSTR , to determine the effect of residence time onto the reaction extent of conversion and lastly to determine the reaction rate constant. The CSTR scale for this experiment is 40LSOLTEQ-QVF Continuous Stirred Tank Reactor (Model: BP 143) . Before the experiment was begun, the general start up was must be run first. The material used for this experiment is NaOh and Et(Ac) which produce Na(Ac) and EtOH. The first experiment, we used the volumetric flow rate of 0.1L/min. After 5 minutes, the sample was taken and back titration was done for the sample to find out the concentration NaOH at the exit of the CSTR. Then the experiment was repeated with different flow rate which are 0.15L/min, 0.20L/min, 0.25L/min and 0.30L/min. The calibration curve also being plotted to determine the conversion of the material. After all the data had been taken, the rate law value and rate constant were being calculated. Different flow rate give different rate constant and rate law. 2.0 INTRODUCTION Continuous stirred-tank reactors (CSTRs) are open systems, where material is free to enter or exit the system, that operate on a steady-state basis, where the conditions in the reactor don't change with time. Reactants are continuously introduced into the reactor, while products are continuously removed. Every instrument used in chemical analysis can be characterized by a specific calibration function. This response function may be linear, logarithmic, exponential, or any other appropriate mathematical form. The exact form of this response function depends on the system being measured and the measurement process itself. While the calibration function may be known theoretically, various factors (such as the specific analyze being measured, interference effects caused by other components of the sample matrix, or random experimental errors) require that we calibrate each instrument for the specific analyze and measurement conditions to be used in a particular experiment. Saponification is a process that produces soap, usually from fats and lye. For the reaction of NaOH and Et(Ac) will produce the Na(Ac) and also ethanol. The conversion are depends on the flow rate of the CSTR. The higher the flow rate, the higher the conversion. Since this is the second order of reaction. The reaction equation is : NaOH + Et(Ac) --> Na(Ac) + EtOH Or A + B --> C + D For a second order of reaction with the same initial concentration (Cao = Cbo) -ra = kCACB = kCA2 -rA = Vcstr /FaoX Thus the volume of reactor is : Vcstr = Fao/kCA2 = Fo(CAo . To determine the effect of residence time onto the reaction extent of conversion 3.3.CA) /τCA2 The residence time of a chemical reactor or vessel is a description of time that different fluid element spend inside the reactor given by : . To determine the reaction rate constant 4.CA) / kCA2 So the rate constant is: k= (CAo .0 OBJECTIVE: 1. The reaction will be carried out using equimolar feeds of both the reactants with same initial concentration. To carry out a saponification reaction between NaOH and Et(Ac) in a CSTR 2. the rate of reaction depends on both of these reactants.0 THEORY The reaction is to study saponification reaction of NaOH and Et(Ac). Therefore by differentiating above equation. providing the percent of material that has a RTD of time t or less F (t ) [ Ci . . The residence time distribution function E(t) is given E (t ) Ci (t ) Ci (t )dt By substituting this equation: Ci (t ) Co e t / Into above equation and solving.out Co ]step By definition. E (t ) e t / The ideal cumulative concentration distribution . E(t) = -dF (t)/dt for a negative step input. we obtain the following expression which describe the amount of a time tracer spends in the reactor. we can obtain the residence-time distribution function for a non-ideal CSTR.τ= Vcstr Fo This equation gives the concentration of species i in the outlet stream at any time.t. F(t) is also practical when evaluating the residence time distribution. 0 APPARATUS SOLTEQ-QVF Continuous Stirred Tank Reactor (Model: BP 143) .5. The steady state conductivity value was recorded and the concentration of NaOH in the reactor and extent of conversion from the calibration curve was find out using equation given. Both pumps P1 and P2 were opened simultaneously and valves V5 and V10 were opened to obtain the highest possible flow rate into the reactor. Reactor was filled up with both the solution until it is just about to overflow. 0.0 PROCEDURES: 1.20. Stirrer M1 was set the speed to about 200 rpm. 6.30 L/min. 5. . Experiment was repeated with flow rate of 0. Valve V12 was opened and collect a 50 mL sample was collected. Back titration was carried out to manually determine the concentration of NaOH in the reactor and extent of conversion. 3.25 and 0. 9.1 L/min. 4. 8.15.6. Valves V5 and V10 was adjusted to give a flow rate of about 0. 0. General start-up procedures was performed 2. 1 0.15 133 56 4.0 RESULT A) Sample Table for Calibration Curve Conversion (%) 0 25 50 75 100 Solution mixture 0.1M NaOH 0.30 0.0250 0.60 66 2.2 -9 57 4 28.394 0.38 3.15 0.20 200 2.04 8.0125 0.76^4 276 0.10 0.10 200 58 6.X (%) 1 27.71 3. τ (min) Conducti vity (mS/cm) Exit Concentra tion of NaOH CNaOH (M) Conversi on .20 0.35 2 -9 56 3 28.0375 0.1M Et(Ac) 100mL 75mL 50mL 25mL - 25mL 50mL 75mL 100mL Concentration of NaOH (M) H20 100mL 100mL 100mL 100mL 100mL Conductivity (mS/cm) 0.25 80 58 2.5 0. Fo (L/min) Residence Time.90^4 690 0.0500 0.76^4 476 0.30^4 230 .2-9 58 5 28.51^4 351 0.30 0.000 14.50 80 2.37 3.25 0.8 -9 58 No NaOH (L/min) Flow rate (L/min) τ (min) X k -rA (mol/L.9 0.20 0.20 100 57 3.15 0.38 2 -9 58 2 28.min) 0.40 100 2.7.5 0.04 1.38 2.3 0.25 0.115 B) Table for recorded data Temperature Flow Rate of (˚C) Flow Rate Of Et(Ac) (L/min) Total Flow Rate of Solutions.30 133 2.30 66 58 2.10 0. Graph conductivity versus conversion Conductivity (mS/min) X (%) Figure 1 . Graph residence time versus conversion X (%) Figure 2 8.25 mol/L Volume of titrated NaOH =24 ml Concentration of NaOH used for titration = 0.o = C NaOH .o=0.o / 2 = 0.05 M .1 mol/L CNaOH.1 mol/L Volume of HCl for quenching =10 ml Concentration of HCl in standard solution =0.CNaOH.1M/2 =0.1 L/min Volume of sample = 50 ml Concentration of NaOH in the feed vessel .0 CALCULATION * For flow rate 0. 1 24 0.25 =9.0004/ (50 x 1000) = 8-9 M * Other calculation are recorded in the table .s V1 0.V2 =10 .V2 = = C NaOH .s x V3)/1000 = (0.0004 mol n2 = 0.4mL n1 = (Chcl.9. s C HCL .25 x 0.6 =0.6 mL V3 = VHCL.4)/1000 =0.0004 mol CNaOH = n2/(Vs x 1000) = 0.s . . For this experiment. but it is also corrosive and can damage the eye. the reaction rate constant is decrease as the volumetric flow rate is increase. For the industrial scale. when the ‘k’ value is increase it means that more volume of NaOH requires to convert just a mole of NaOH in second. When both solutions mixed. The longer the time of the reactant spend. There is more moles of NaOH converted for a less volume of NaOH solution requires. glove must be wear. the rate of reaction is L/mol.0 DISCUSSION The calibration curve was plotted to determine the conversion of the reaction between NaOH and Et(Ac) at certain value of conductivity.9.s. . The conductivity increase when the concentrations decrease. It is found that the conversion increase when the flow rate decrease. There are also a few precaution that need to be taken during handling the experiment. we can see that the conductivity of the of NaOH varied linearly with the concentration of NaOH. From the graph. In other word. Fluid entering the reactor at time . it is very important to get high value of conversion. Both reactant give different value of conductivity when mixture of different moles was used. First of all. it means that less mole of NaOH converted for a big volume of NaOH solution. As the Et(Ac) is not an electric conductor. Relate to the reaction rate constant for this order of reaction. So it say that reaction rate increase when rate constant decrease. The reaction between equimolar of NaOH and Et(Ac) is the second order. t will exit the reactor at time t+ where is the residence time of the reactor. make sure before doing the experiment. the higher product concentration. Even the concentration low. This is because the substance used for titration is an acid solution. Volumetric flow rate is related to the residence time and that is the reason why flow rate of both solution were varies. the conductivity of the mixture measurement can be used to measure the concentration of unreacted NaOH that remains solution that relate to conversion. NaOH act as reactant and finally sodium acetate was produced. Residence time is the time that the fluid elements spend within reactor. we have learnt on how to carry out saponification reaction between NaOH and Et(Ac) in CSTR and we have determine the effect of residence time onto the reaction extent of conversion. So this experiment was succeeded. when handling the experiment .10. 11.0 RECOMMENDATION There a few recommendation that need to be considered during this experiment. we have determined the reaction rate constant. Lastly. Firstly. CONCLUSION As the conclusion.