Elementary Reactions

Transcription

1 Updted: 6 Mrh 08 Print versin Leture #5 Kinetis nd Thermdynmis: Fundmentls Kinetis nd Anlysis Kineti Dt (Benjmin,.6) (Stumm & Mrgn, Chpt. ) (pp.6 0; 69 8) Dvid Rehw CEE 680 #5 Elementry Retins When retnt mleules llide with the right rienttin nd energy level t rm new nds Mny servle retins re relly just mintins elementry retins Strting ut with sme A nd B, we serve tht E nd F re the end prduts A B C D C E A D C F A B E F slw st st Dvid Rehw CEE 680 #5

2 Cnt. S&M: Fig.. Pg. 7 Elementry retins A single step in retin sequene Invlves r retnts nd r prduts Cn e desried y lssil hemil inetis Dvid Rehw CEE 680 #5 3 Kinetis Exmples Fe + xidtin y O lmst instntneus t high ph quite slw t lw ph high D.O. my help Oxidtin rgni mteril Frmtin slid phses Aluminum hydrxide Qurtz snd Dvid Rehw CEE 680 #5 4

3 Kinetis Bse Hydrlysis dihlrmethne (DCM) Frms hlrmethnl (CM) nd hlride Clssi send rder retin (mleulrity ) Rte [ DCM ][ OH d[ DCM ] d[ OH ] First rder in eh retnt, send rder verll ] d[ CM ] d[ Cl ] Dvid Rehw CEE 680 #5 5 Retin Kinetis Irreversile retin is ne in whih the retnt(s) preed t prdut(s), ut there is n signiint wrd retin, In generlized r, irreversile retins n e represented s: A + B Prduts i.e., the prduts d nt remine r hnge t rm retnts in ny ppreile munt. An exmple n irreversile retin is hydrgen nd xygen mining t rm wter in mustin retin. We d nt serve wter spntneusly seprting int hydrgen nd xygen. Dvid Rehw CEE 680 #5 6 3

4 Retin Kinetis: Reversiility A reversile retin is ne in whih the retnt(s) preed t prdut(s), ut the prdut(s) ret t n ppreile rte t rerm retnt(s). A + B pp + qq Mst retins must e nsidered reversile An exmple reversile ilgil retin is the rmtin densine triphsphte (ATP) nd densine diphsphte (ADP). All living rgnisms use ATP (r similr mpund) t stre energy. As the ATP is used it is nverted t ADP, the rgnism then uses d t renvert the ADP t ATP. Dvid Rehw CEE 680 #5 7 Kineti priniples Lw Mss Atin Fr elementry retins A B rte C C A B prduts where, C A = nentrtin retnt speies A, [mles/liter] C B = nentrtin retnt speies B, [mles/liter] = stihimetri eiient speies A = stihimetri eiient speies B = rte nstnt, [units re dependent n nd ] Dvid Rehw CEE 680 #5 8 4

5 Retin Kinetis (nt.) Retins rder n in retnt When n=0, we hve simple zer rder retin Cnentrtin n Slpe Dvid Rehw CEE 680 #5 9 0 mg/ l/ min t 0 0 Time 40 (min) Retin Kinetis (nt.) When n=, we hve simple irst rder retin This results in n expnentil dey Cnentrtin Dvid Rehw CEE 680 # min e t Time (min) 5

6 Retin Kinetis (nt.) This equtin n e linerized gd r ssessment rm dt Cnentrtin (lg sle) 00 Slpe min ln ln t Time (min) Dvid Rehw CEE 680 #5 Retin Kinetis (nt.) When n=, we hve simple send-rder retin 90 This results in 80 n espeilly wide rnge in 50 rtes t 40 Mre typil t L/ mg/min hve nd rder 0 in eh tw 0 dierent 0 retnts Time (min) Cnentrtin Dvid Rehw CEE 680 #5 6

7 Retin Kinetis (nt.) Agin, the equtin n e linerized t estimte rm dt t /Cnentrtin Time (min) Dvid Rehw CEE 680 # Slpe L/ mg/min Cmprisn Retin Orders Curvture s rder hnges: nd > st >zer Cnentrtin Zer Order First Order Send Order Time (min) Dvid Rehw CEE 680 #5 4 7

8 Retin Kinetis (nt.) Fr mst retins, n= r eh tw dierent retnts, thus send rder verll retin 3.9x0 5 Lmg min Mny these will hve ne retnt in gret exess These eme pseud st rder in the limiting retnt, s the retnt in exess relly desn t hnge in nentrtin Dvid Rehw CEE 680 #5 5 Cnentrtin Retin Kinetis (nt.) s e s Time (min) t 3.9x min 5 Sine C hnges little rm its initil 80 mg/l, it is mre interesting t (80) us n C C exhiits simple st rder dey, lled pseud st rder The pseud st rder rte nstnt is just the served rte r s Dvid Rehw CEE 680 #5 6 8

9 Vrile Kineti Order Any retin rder, exept n= n n t n n n n n t Dvid Rehw CEE 680 #5 7 Hl lives Time required r initil nentrtin t drp t hl, i.e.., =0.5 Fr zer rder retin: t 0.5 t Fr irst rder retin: e t 0.5 t 0.5 Dvid Rehw CEE 680 #5 8 e t t ln()

10 Retins in Series A 3 B C D = = 3 =0. dy - Fig..9 Pg. 68 Dvid Rehw CEE 680 #5 9 Reversile retin inetis Fr generl reversile retin: A + B pp + qq And the rte lw must nsider th rwrd nd reverse retins: r A = C A C B - C p P CQ q where, = rwrd rte nstnt, [units depend n nd ] = wrd rte nstnt, [units depend n nd ] C P = nentrtin prdut speies P, [mles/liter] C Q = nentrtin prdut speies Q, [mles/liter] p = stihimetri eiient speies P q = stihimetri eiient speies Q Dvid Rehw CEE 680 #5 0 0

11 Reversile st rder retins Kineti lw db [ A] [ B] Eventully the retin slws nd, Retnt nentrtins pprh the equilirium vlues db 0 [ A] [ B] [ B] K eq [ A] Fig..0 Pg. 69 Dvid Rehw CEE 680 #5 Temperture Eets Temperture Dependene Chemist's Apprh: Arrhenius Equtin Ativtin energy d(ln ) E Pre-expnentil Ftr E / RT dt RT T Ae e T T 93 0 K E ( T 93)/ RT 93 Engineer's Apprh: C T0 C Or mre generlly where T is ny seline temperture T T Dvid Rehw R = universl gs nstnt =.987 l/ K/mle T = slute temp ( K) Typil vlues: =.0 t.5 T T

12 Determintin E nd A Use Arrhenius equtin Te nturl lg th sides Evlute slpe nd interept T Ae E / RT E ln T ln A R T Dvid Rehw CEE 680 #5 3 Ctlysis G A Ctlyst enhnes rtes retnts y prviding lterntive pthwys with lwer tivtin prduts energies Retin rdinte It is nt nsumed in the retin Hmgeneus Aid/se tlysis Tre metl tlysis Hetergeneus Retins n prtile sures Retins medited y mirrgnisms (enzymes) Engineered sure tlysis Ctlyti nverters, tivted rn G Dvid Rehw CEE 680 #5 4

13 Anlysis Rte Dt Integrl Methd Lest squres regressin linerized rm Dierentil Methd estimte instntneus rte t nwn time nd retnt nentrtin Initil rte Methd mre rigrus, ut slw Methd Exess nly when r mre retnts re invlved Dvid Rehw CEE 680 #5 5 Kineti mdel r equilirium Cnsider retin s llws: A + B = C + D Sine ll retins re reversile, we hve tw pssiilities A B C D A B C D r The rtes re: { A}{ B} { C}{ D} And t equilirium the tw re equl, r =r We then deine n equilirium nstnt (K eq ) K eq r { A}{ B} { C}{ D} { C}{ D} { A}{ B} Dvid Rehw CEE 680 #5 6 3

14 Kineti mdel with mles In terms mlr nentrtins, the rtes re: r A A B B r C C D D And t equilirium the tw re equl, r =r A A B B C C D D And slving r the equilirium nstnt (K eq ) K eq C C D A B A D B C D AB C D A B Dvid Rehw CEE 680 #5 7 T next leture Dvid Rehw CEE 680 #5 8 4