Densities and viscosities of aqueous ternary mixtures of 2-amino-2-methyl-1-propanol with ethylenediamine from to K

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1 Destes ad vscostes of aqueous terary mxtures of 2-amo-2-methyl-1-propaol wth ethyleedame from to K Rega V. trolzo R&D Ceter for Membrae Techology ad Departmet of Chemcal geerg Chug Yua Chrsta Uversty Chug L 32023, Tawa, ROC Meg-Hu L* R&D Ceter for Membrae Techology ad Departmet of Chemcal geerg Chug Yua Chrsta Uversty Chug L 32023, Tawa, ROC mhl@cycu.edu.tw (M.-H. L) Abstract Destes ad vscostes of aqueous terary solutos of 2-amo-2-methyl-1-propaol (AMP) wth ethyleedame (DA) were determed over a wde rage of temperatures ( to K) ad compostos. The obtaed expermetal data for desty ad vscosty were represeted as a fucto of temperature ad ame cocetrato usg a Redlch-Kster-type ad Vogel Tamma Fulcher equato, respectvely. The pre dcted data agree well wth the expermetal data suggestg that the appled models were satsfactory. Keywords 2-amo-2-methyl-1-propaol, desty, vscosty ethyleedame, I. INTRODUCTION Alkaolames ad ther bleds have bee the focus of may researches due to sgfcat applcatos the atural gas dustry, ol referes, petroleum chemcal plats, ad sythetc ammoa plats for the removal of acdc compoets such as CO 2 ad H 2 S from gas streams [1]. Aqueous solutos of ame bleds have demostrated hgh effcecy CO 2 absorpto tests as a result of combed stregths of each ame system whch lead to cosderable savgs eergy requremets ad cost [1]. A hghly relevat ame classfcato s the stercally hdered ames, such as 2-amo-2-methyl-1-propaol (AMP), whch possess a bulky group attached to the ame that allows more CO 2 to bd per molecule. Ths sterc hdrace s the key factor to acheve hgh thermodyamc capacty, fast absorpto rates at hgh CO 2 loadgs [2] ad lower regeerato eergy requremet [3]. I earler publcatos, ketc data of ethyleedame (DA) was superor tha the covetoal mooethaolame (MA) soluto ad suggests that t reacts wth CO 2 more rapdly [4, 5]. The study of Kemper et al. [3] shows that addto of DA to AMP results ehaced solvet performace durg absorpto of 100% CO 2. Dames are potetal alteratves CO 2 capture due to the added reactve ame fuctoalty that allows a hgher bdg capacty ad faster reacto ketcs [6]. The am of ths study s to provde desty ad vscosty data for the aqueous terary AMP/DA mxtures. The overall selecto of a good solvet requres kowledge of ts physcal propertes whch are appled the effcet desg, smulato, ad operato of acd gas treatmet equpmet [7]. Accordg to [8], soluto desty ad vscosty have sgfcat fluece the mass trasfer of CO 2 aqueous solutos ad thus are ma essetals the optmal desg of absorpto cotactors. The values of these physcal propertes are ofte tegrated to calculatos of dffuso parameters process models [9]. These reasos cosdered, determato of accurate physcal propertes that covers a wde rage of temperatures ad composto s mportat. A thorough revew of the lterature, however, shows lackg of thermodyamc property data for the system studed. I ths work, propertes are measured at 30 wt% total ame cocetrato the temperature rage ( to ) K. The depedece of temperature ad cocetrato of AMP ad DA to these physcal propertes are correlated based o the expermetal data. II. XPRIMNTAL A. Chemcals 2-Amo-2-methyl-1-propaol (AMP, Acros Orgacs, 99%) ad ethyleedame (DA, Alfa Aesar, 99%) was obtaed from Acros Orgacs ad Alfa Aesar, respectvely, ad used wthout further purfcato. A detaled descrpto of the chemcals used are preseted Table 1. All solutos were prepared by mass usg a aalytcal balace (Mettler Toledo, model AL204) havg a precso of ± g. Dstlled water of Type 1 reaget-grade (resstvty = 18.3 MΩ cm) was deozed usg a compact water purfcato system (Barstead Thermodye asy Pure LF) before all sample preparatos. The aqueous solutos were degassed va a ultrasoc cleaer (Braso, Model 3510) pror to property measuremets. 163

2 TABL I. DSCIRPTION OF CHMICALS USD Chemcal ame Abbrevato CAS o. Molar mass Chemcal formula Chemcal structure 2-Amo-2-methyl-1-propaol AMP C 4H 11NO thyleedame DA C 2H 8N 2 B. Desty Destes, ρ, were measured at 5 K tervals, at dfferet temperatures ( ad K), usg a SVM 3000 desty meter (Ato Paar GmbH) that operates through the prcple of a oscllatg U-tube as descrbed [10, 11]. The estmated ucertates for temperature ad desty measuremet were ±0.02 K ad ± g cm 3, respectvely. Pror to all desty measuremets, calbrato was performed usg degassed deosed water at the temperature rage cosdered ths study. Results are preseted Table 2 ad show a good agreemet (AAD = 0.003%) betwee the measured data ad the stadard referece values [12]. Ths suggests that future measuremets are of acceptable accuracy. C. Vscosty Vscosty (η) measuremets were doe usg a automated fallg ball mcrovscometer (Ato Paar GmbH, model AMV). The strumet has a bult- Pt-100 temperature sesor for temperature cotrol ad measuremets, ad operated based o the prcple of fallg ball vscometry accordace wth DIN ad ISO The sample was TABL II. T (K) COMPARISON OF THRMOPHYSICAL PROPRTIS OF WATR Desty, ρ (g cm 3 ) Vscosty, η (mpa s) Wager et al. a Ths work Wager et al. a Ths work AAD b b. AAD(%) (100 / ) - / 1 exp t, ref, exp t, a. Referece values take from [12]., where s the umber of data pots. flled to a dagoally mouted glass capllary (dameter d = 1.6 mm) where a sold steel ball was allowed to roll uder the fluece of gravty. At dfferet agles of clato ad set temperatures, the ball s rollg tme was cosdered for the vscosty determato. Before the seres of measuremets, calbrato usg water was doe to ascerta the accuracy of the method used. The calbrato s detaled further [10]. Table 2 shows that measured values agree well to referece values [12] wth a AAD of 0.606%. The estmated ucertates for the measuremets of tme, temperature, ad vscosty were ±0.002 s, ±0.05 K, ad ±1.0%, respectvely. All property determato were carred out three to fve replcate rus ad obtaed expermetal values represet the mea of three measuremets. III. RSULTS AND DISCUSSION A. Desty The destes of AMP + DA + water terary system were measured at temperature rage from ( to ) K ad the expermetal values are reported Table 3. A decreasg tred of destes s observed at the addto of DA as see Fgure 1. The lower desty values of DA cotrbuted to the TABL III. T (K) wt% AMP/ wt%da XPRIMNTAL DNSITIS OF AMP + DA + WATR AT TMPRATURS FROM TO K ρ (g cm 3 ) 0/30 5/25 10/20 15/15 20/10 25/5 30/

3 1.00 System Parameters AAD a (%) α,0 α,1 Desty (gcm -3 ) Cocetrato AMP (wt%) Fg. 1. xpermetal ad calculated desty results for the aqueous mass%amp + mass%da solutos as a fucto of AMP cocetrato at varous temperatures:, K;, K;, K;, K;, K;, K;, K;, K;, K. The les represet calculated values usg a Redlch-Kster-type equato. reduced values recorded for the mxtures. At the same cocetrato, the desty of the solutos decreased accompayg a crease temperature whch s deduced as a effect of thermal expaso of the lqud. A Redlch-Kster-type equato for the excess molar volume was appled to correlate the desty of lqud mxtures. For bary mxtures, the equato takes the form: V12 x1x2 A x1 x2 0 temperatures [13]. ( - ) where A are adjustable parameters, ad represets a teger varyg from 1 to a umber that s justfed by the data. The temperature depedece of A was assumed to follow the relato,0,1 A a a T T (K) η (mpa s) Here, a,0, a,1 are emprcal costats ad T s the absolute temperature K. The excess molar volume of the lqud mxture for terary systems was gve by the followg expresso V V V V The excess volume of the lqud mxtures was calculated by the expermetal desty data accordg to (4) TABL IV. V ( x M ) ( x M ) 1 1 PARAMTRS OF TH RDLICH-KISTR-TYP QUATION FOR TH DNSITY OF AQUOUS TRNARY MIXTURS AMP + DA + H 2 O a , where s the umber of data pots. Note that V s the excess molar volume cm 3 mol 1, x s the mole fracto of the compoet the mxture, ad M s ts molar mass. ρ ad ρ correspod to the measured destes g cm 3 of the mxture ad pure compoet, respectvely. I the equatos metoed above, the optmzed values of the emprcal parameters were obtaed by fttg (1), (2), (3) ad (4) to the expermetal data, usg the method of least squares. The coeffcets for use these equatos are preseted Table 4 ad shows a acceptable average absolute devato (AAD%) of about 0.006% for a total of 126 data pots. B. Vscosty Preseted Table 5 are the determed vscostes for the terary AMP/DA mxtures. The behavor of ths system s graphcally show Fgure 2 as a fucto of temperature. It s otced that added DA the system otceably mproves the vscosty. Low solvet vscosty s desred durg CO 2 removal sce t makes the lqud easer to hadle dustral applcatos. It ca allow good mass trasfer rates ad packg requremets ca be optmzed, especally at reduced Referece [14] metoed that vscosty-temperature depedece for dfferet mxtures ca be determed usg the Vogel Tamma Fulcher (VTF) type asymptotc expoetal fucto whch ca be expressed the followg geeral form: TABL V. XPRIMNTAL VISCOSITIS FOR TH AMP/ DA AQUOUS SOLUTIONS AT T MPRATURS FROM TO K wt%amp/ wt%da AAD(%) (100 / ) - / 1 exp t, pred, exp t, 0/30 5/25 10/20 15/15 20/10 25/5 30/

4 Vscosty (mpas) the expermetal data o (8) ad (9). Results are preseted l lc Table 6 whch show a good agreemet of predcted values ad R( T Tc ) the expermetal vscostes of the AMP/DA/H 2 O system as represeted by the low AAD of 0.152% for a total of 63 data pots. Predcted data are llustrated as smooth curves Fgure 2. The proposed modfed VTF equato ca be regarded as acceptable to model the vscosty data gathered ths study. I ths equato, η s the temperature-depedet vscosty mpa s, η c s a pre-expoetal coeffcet, T ad T c are the actual ad crtcal-lmt absolute temperatures of the system studed. Further, s the actvato eergy of the process cosdered ad R s defed as the uversal gas costat. For T c = 0 K, (5) reduces to a basc Arrheus equato of the expresso TABL VI. FITTING PARAMTRS OF (8) AND (9) FOR TH VISCOSITY OF AQUOUS AMP/DA TRNARY MIXTURS System l lc RT ( ) Parameters AAD a (%) b,0 b,1 b,2 AMP + DA + H 2 O I order to clude effects of both temperature ad composto o vscosty, a modfed form was proposed where a secod-order term was added to (6) ad expressed terms of B ( = 1 to 3): a AAD(%) (100 / ) - / 1 exp t, pred, exp t,, where s the umber of data pots. 2 3 l B B B 1 2 T T IV. CONCLUSION The destes ad vscostes of the aqueous mxtures of 2- I terms of vscosty, (7) ca be wrtte as amo-2-methyl-1-propaol (AMP) + ethyleedame (DA) + water were measured from to K wth the total ame mass fracto the soluto kept at 30 wt%. It was B2 B3 l expb1 2 observed that creasg the DA cocetrato leads to a T T decrease both the desty ad vscosty of the soluto. At the same cocetrato, a rase temperature decreases ther where T s K ad B s assumed to be parameters values. The proposed models used to predct data were the depedet o the ame mole fracto the mxture wth the Redlch-Kster-type ad Vogel Tamma Fulcher equato expresso for desty ad vscosty, respectvely. The results were satsfactory ad are geerally acceptable for use egeerg applcatos, especally for desg ad smulatos. B b b x b x 3.2 2,0,1 1,2 1 ACKNOWLDGMNT Ths research was supported by a grat (MOST MY3) from the Mstry of Scece ad Techology of the Republc of Cha Temperature (K) Fg. 2. Plot of vscosty of AMP + DA + H 2O solutos at 30wt% total ame as a fucto of temperature ad composto (wt% AMP/ wt% DA):, 0/30;, 5/25;, 10/20;, 15/15;, 20/10;, 25/5;, 30/0. Les are predcted values usg Vogel Tamma Fulcher equato. Mole fracto of the ame are deoted by x 1 whle b,0, b,1 ad b,2, are emprcal costats determed by a lear ft of RFRNCS [1] L.-F. Chu, ad M.-H. L, Heat Capacty of Alkaolame Aqueous Solutos, Joural of Chemcal & geerg Data, vol. 44, o. 6, pp , 1999/11/01, [2] T. Chakravarty, U. K. Phuka, ad R. H. Welud, Reacto of acd gases wth mxtures of ames, Joural Name: Chem. g. Prog.; (Uted States); Joural Volume: 81:4, pp. Medum: X; Sze: Pages: 32-36, [3] G. Sartor, ad D. W. Savage, Stercally hdered ames for carbo doxde removal from gases, Idustral & geerg Chemstry Fudametals, vol. 22, o. 2, pp , 1983/05/01, [4] J. Kemper, G. wert, ad M. Grüewald, Absorpto ad regeerato performace of ovel reactve ame solvets for post-combusto CO2 capture, ergy Proceda, vol. 4, o. 0, pp , [5] A. He, J. L, ad P. Totwachwuthkul, Reacto Ketcs of CO2 Aqueous 1-Amo-2-Propaol, 3-Amo-1-Propaol, ad Dmethylmooethaolame Solutos the Temperature Rage of K Usg the Stopped-Flow Techque, Idustral & 166

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