Tutorial 3 solutions Lecturer: Miss Anis Atikah Ahmad Tel: +604 976 3245 Email: anisatikah@unimap.edu.my

Questions Write the rate laws for the following reactions assuming each reaction follows an elementary rate laws. C2H6 → C2H4 + H2 (CH3)3COOC(CH3)3 ⇌ C2H6 + 2CH3COCH3 Write the rate law for the reaction: 2A + B → C if the reaction is second order in B and overall third order, is zero order in A and first order in B is zero order in both A and B is first order in A and overall zero order

The formation of ortho-nitroaniline is formed from the reaction of ortho-nitrochlorobenzene (ONCB) and aqueous ammonia. The liquid-phase reaction is first order in both ONCB and ammonia with k= 0.0017 m3/kmol-min at 188°C with E = 11,273 cal/mol. The initial entering concentration of ONCB and ammonia are 1.8 kmol/m3 and 6.6 kmol/m3 respectively. Write the rate law for the rate of disappearance of ONCB in terms of concentration. Set up stoichiometric table for this reaction for a flow system. Explain how part (a) and (b) would be different for a batch system. Write –rA solely as a function of conversion. What is the initial rate of reaction (X=0) at 188°C and at 25°C? What is the rate of reaction when X = 0.9 at 188°C and at 25°C? What would be the corresponding CSTR volume at 25°C to achieve 90% conversion at 188°C for a feed rate of 2 dm3/min

Question (1) Write the rate laws for the following reactions assuming each reaction follows an elementary rate laws. C2H6 → C2H4 + H2 (CH3)3COOC(CH3)3 ⇌ C2H6 + 2CH3COCH3 (a) (b) C2H6 → C2H4 + H2 A → B + C (CH3)3COOC(CH3)3 ⇌ C2H6 + 2CH3COCH3 A ⇌ B + 2C

Question (2) (a) (b) (c) (d) Write the rate law for the reaction: if the reaction is second order in B and overall third order is zero order in A and first order in B is zero order in both A and B is first order in A and overall zero order (a) (b) (c) (d)

Question (3)(a) Let A = ONCB, B = NH3, C = Nitroaniline , D = NH4Cl The formation of ortho-nitroaniline is formed from the reaction of ortho-nitrochlorobenzene (ONCB) and aqueous ammonia. The liquid-phase reaction is first order in both ONCB and ammonia with k= 0.0017 m3/kmol-min at 188°C with E = 11,273 cal/mol. The initial entering concentration of ONCB and ammonia are 1.8 kmol/m3 and 6.6 kmol/m3 respectively. Write the rate law for the rate of disappearance of ONCB in terms of concentration. Let A = ONCB, B = NH3, C = Nitroaniline , D = NH4Cl

Question (3)(b) Species Entering Change Leaving A B C D A + 2B → C + D Set up stoichiometric table for this reaction for a flow system Species Entering Change Leaving A B C D

Question (3)(c) Explain how part (a) and (b) would be different for a batch system For batch system,

Question (3)(d) Write –rA solely as a function of conversion. For liquid phase rxn, υ = υ0

Question (3)(d) Substituting the concentration of A & B;

Question (3)(e) What is the initial rate of reaction (X=0) at 188°C and at 25°C i) At T= 188°C, k =0.017m3/kmol-min Substituting X=0 and k =0.017m3/kmol-min into (1); ---(1)

Question (3)(e) What is the initial rate of reaction (X=0) at 188°C and at 25°C ii) At T= 25°C (298.15 K), k =? m3/kmol-min Find k at T =25°C first k at initial T is k at any temperature is Taking the ratio; ---(1)

Question (3)(e) What is the initial rate of reaction (X=0) at 188°C and at 25°C ii) Now we know that, at T= 25°C (298.15 K), k = 2.039 x 10-6 m3/kmol-min Therefore, we can calculate –rA at 25° by susbtituting k= 2.039 x 10-6 m3/kmol-min, and X = 0 in eq (1). ---(1)

Question (3)(f) (i) At T= 188°C, k =0.0017m3/kmol-min What is the rate of reaction when X = 0.9 at 188°C and at 25°C? (i) At T= 188°C, k =0.0017m3/kmol-min Substituting X=0.9 and k =0.017m3/kmol-min into (1); ---(1)

Question (3)(f) What is the rate of reaction when X = 0.9 at 188°C and at 25°C? (ii) From part (e) when T= 25°C, k = 2.039 x 10-6 m3/kmol-min Substituting X=0.9 and k = k = 2.039 x 10-6 m3/kmol-min into (1); ---(1)

Question (3)(g) What would be the corresponding CSTR volume at 25°C to achieve 90% conversion at 188°C for a feed rate of 2 dm3/min? Substituting the value of CA0, υ0 and –rA(at 288°C & X=0.9);