Công nghệ tổng hợp glycerol carbonat góp phần làm tăng hiệu quả sản xuất nhiên liệu diesel sinh học

CBESBB& CONG NGHE TONG HOP GLYCEROL CARBONAT GOP PHAN LAM TANG HIEU QUA SAN XUAT NHIEN LIEU DIESEL SINH HOC TECHNOLOGIES FOR GLYCEROL CARBONATE SYNTHESIS, CONTRIBUTING TO EFFICIENCY ENHANCEMENT OF BIODIESEL PRODUCTION Bin Tda soan 10-06- 2014 GS TSKH Mai Tuyen Hgl Xuc tac va Hap phu Vidt Nam ABSTRACT The extensible development of biodiesel based on transesterification of triglycerides from vegetable oils and animal fats with methanol surely remains considerable amounts of glycerol Transfonmation of glycerol into value-added compounds, such as glycenDl carbonate, can increase greatly economic effects of biodiesel production For the synthesis of glycerol carbonate from glycerol the catalytic processes play important role The catalytic reactions in the convereion of glycerol into glycerol carbonate are addressed in this review Tif khoa: diesel sinh hpe, glycerol, glycerol carbonat, qua trinh xde tac, dimethyl carbonat urS, carbon dioxide, glycerol hda, qua trinh chuyin ddi este hda MO D A U Nhien lieu diesel sinh hpe (biodiesel) dang la mdt hudng phat t r i l n thdi s y va hdp dan, thu hdt s y quan tam sau sac tren the gidi va b nudc ta Tuy nhien, cho den nay, biodiesel van chua duoc phat trien dd manh, de ed kha nang giai dap mdi lo lang ve s y thieu hut dau mo va tinh trang d nhiem mdi trUdng NguySn nhan ehinh la gia cda biodiesel van cdn eao hon kha nhieu so vdi nhien lieu diesel tUdau md Gia cda biodiesel phu thupe nhieu vao viec tan dung ngudn nguyen lieu dua vao san xudL Biodiesel hay methyl este eda acid beo (fatty acid methyl ester hay FAME) la san pham cda qua trinh chuyen doi este hoa (transesterification) cae triglyceride dau thuc vat hay m d dpng vat bang methanol cac dieu kien xue tae axit bay baza KS't qua cda qua trinh dd la, e d ba phan td methanol cd t h i chuyen hod dupc mpt phan t d triglyceride thdnh ba phan t d FAME va mdt CIVHC - SO / phan td glycerol NhU vay, qua trinh sdn xuat biodiesel di lai mpt lupng Idn glycerol, nhu mpt san pham phu Lupng glycerol dd tUong duong vdi 10% lUpng biodiesel duoc san x u l t S y d u t h U a s a n lupng glycerol mdi chi dupe dung de san xuat nang lupng b i n g cdch dot chay Ve tiem nang s d dyng, glycerol carbonat (4-hydroxymethyl-1,3-dioxolan-2-one) la mdt nhdng dan xuat eua glycerol hien gianh dupe s y ehd y manh me ca ve khoa hpc vd cdng nghiep Glycerol carbonat la c h i t thay the xanh eho eae hpp chat quan trpng thu dtigc tti dau mo, nhu etyien carbonat hay propylen carbonat Sy phPt trien cdng cac phuong phap san xudt glycerol carbonat tu nlidng nguyen lieu tai tao chae c h i n la npi dung quan trpng ddi vdi cae ngPnh cdng nghiSp khae nhau, vi mpt san p h l m ed gia trj cd the thu dupe vdi khoi lupng Idn vd gia ha, ed t h i eanh tranh dupc vdi eae hpp c h i t di td dau md NhU vay, san xuat glycerol carbonat cd ddng gdp Idn vao giam gia eda biodiesel thdc day phat t r i l n manh me hdn ngudn nhidn lieu hap dan Dudl day, ehdng tdi gidi thieu ba hudng cong nghS chd yeu tdng hpp glycerol carbonat, dd Id phan Ung gida glycerol vd carbon dioxide, phan Ung eda glycerol vdl urS va phan dng ehuyen ddi este hPa glycerol bang dimethyl carbonat (DMC) PHAN LTNG GIUTA GLYCEROL VA CARBON DIOXIDE Day Id hudng nghiSn cijru h i p d i n , vi ea glycerol va carbon dioxide deu Id nhdng nguySn lieu re tien COz cdn Id khf nhP kfnh, mpt hop chat cd hai ddn mdi trudng, neu c h u y i n hoa dupe COz mdt san pham ed lpi, thi dd la mdt mui ten ban trdng hai dich Phan Ung gida glycerol vd COz xay theo phuong trinh: CHiOH ••• Ct^ CHiOH Michele Aresta va dong tac gia da tien hanh phan dng s d dung chat xuc tac thile, dibutyl - thiec - oxide (n-BuzSnO) va dibutyl-thiee-dimethoxide (n-Bu2Sn(OCH3)2) [1] Phan dng dupc t i l n hdnh autoclave b ap suat MPa COz, nhiet lOO-ISO^C thdi gian 15 gid o a t ludi phPn t d hon hpp phan dng di loai nude tao qua trinh phan dng Trong hai c h i t xdc tac thi chat xdc tae thU hai n-Bu2Sn(OCH3)2 boat dpng hon Tuy nhiSn, mdc dd ehuyen HOH^ hoa glycerol thPnh glycerol carbonat dat thap, chi la 6,86% Khi tien hanh phan Ung giUa glycerol va COz cd mat methanol va s d dung c h i t xdc tae n-BuzSnO cd the dat hieu sua't glycerol carbonat 35% thdi gian gid, d nhiSt dp 120''C va ap s u i t 13,8 MPa, nhu da dUpe Jimil George va ddng tae gia bao cao [2] Vai trd eda methanol dupc xem IP tac nhan hoat hoa chat xue tac, nhU so dd tren hinh sau day: Hinh Sa d6 minh hoa vai trd cda methanol tong hgp glycerol carbonat C^dHC - s d 7/2014 illHIIIil'illil TUso tren day, ed the nhan t h I y , qua trinh tdng hpp glycerol carbonat tU glycerol va carbon dioxide bang xue tae nBuzSnO, methanol da tham gia vao mdt sd giai doan trung gian, tU dd thdc day phan Ung chung dat hieu qua cao hon Trude h i t , hai phan t d methanol phan Ung vdi chat xdc tac de dUa chat xde tae ve dang hoat dpng dibutyl - t h i l c - dimethoxide (2) Tiep theo, phan Ung vdi glycerol tao thdnh dibutyl thiec - glyeerat (4) va tach trd lai hai phan t d methanol Ddn day, phan t d COz chdn vao tao dibutyl-thilc-glyeerat-carbonat (5) Vai trd cda methanol d i n giai doan la tham gia phye hdi chat xue tac b dang va tao glycerol carbonat, sau tach mdt phan t d nUde Cung nghiSn cUu anh hudng eda methanol den phan Ung gida glycerol va COz, edng trinh eda S.Podila va ddng tac gia [3] nhan t h I y phan Ung xay pha long, d dd methanol hda tan dagc ca glycerol, COz vd phUe xdc tac cda thiec Tuy nhien, d ndng dd COz cao hon 0,6 phan mol thi lai xay phan dng phu gida methanol va COz de tao dimethyl carbonat (DMC), nhu mpt san pham phu cda qua trinh Hudng edng nghe tdng hpp glycerol carbonat bang phan Ung giUa glycerol va COz ed the sd dyng nhung chat phan Ung re va chat xue tae IP san pham thuong mai Tuy nhiSn, theo hudng cdng nghS nay, mUe dp ehuyen hoa glycerol chl dat dUpc 35% va phai t i l n hanh phan Ung d ap s u i t cao Mac du vay, theo Nghi T.Nguyen va Yasar Demirel [4], neu k i t hop san x u l t biodiesel vdi san xuat glycerol carbonat edng mpt nhP may, thi du hieu s u i t phan dng eaeboxyl hoa glycerol bang COz bang c h i t xdc tae n-Bu2Sn(0Me)z van edn tha'p, nhUng hidu qua kinh te chung cua nha may van cd the tang PHAN LTNG GlOfA GLYCEROL V A URE Phan L^g gida glycerol va ure hy vong cd the eho hieu qua tdng hpp glycerol carbonat cao hon, vi urS \a san pham thuong mai, re va la dang boat dpng cda COz Phan Ung xay theo phuong trinh sau: NH3 NHjCONHj Hj H = NH3 tach sau phan (>ng CO the (Jiroc thu hoi de tai tao trd lai ure bang phan Crng v6i HjN OH —OH OH Glycerol CNHC - SO / J "~~NH2-• COi Co the hinh dung qua trinh nhu sau: — COj + NH3 \ sL "'^'''"^VXA P\ H2N-^^ N H j Urea Glycerol carb NGHIEN Clin - UNG DUNG Trong thuc te, cae tae gia Dubois JeanLuc va Aresta Michele nhan t h I y qua trinh phan dng gida glycerol va ure xay theo hai giai doan [5] n h u s a u : CH2OH HOH + NH2CNH2 ;HOOH :HOH -NH3 (1) CH2O-CO-NH2 CtLjOH H2 HOH ~/^—d CH2O-CO-NH2 Glycerol Carbamate Trong giai doan 1, phan dng giUa glycerol va ure tao glycerol carbamat, ePn den giai doan thd hai, carbamat chuyen hda glycerol carbonat Ca hai giai doan deu la nhdng phan Ung can bang Mudn c h u y i n can b i n g ve phfa tao san pham, can loai mdt hai san p h l m khol hdn hop phan Ung, hoae la Idi cudn hoi NHs khdi ^=0 + N H (2; Y"2 OH Glycerol cartxjnate khu vuc phan Ung bang cdch tien hdnh phan dng b ap sua't t h I p , hay dung ddng day NHa khdi mdl trUdng phan dng, hoae sd dung dung mdl hoa tan lua ehpn glycerol carbonat Nghien cUu ehi tidt hon, Michele aresta vd ddng tae gia [6] nhan t h I y giai doan ndi trSn lai ed the xay theo hai budc: iipaOOf Ni% -OH -OH I -OH Budc phan td ure phan ly acid isocyanic vp amoniac, cdn d budc 2, acid isocyanlc cong hpp vdi glycerol tao glyceryl carbamat Ca hai boPc d I u xay eo mpt chat xOc tac Phan Ung dupc tien hanh sd dung eha't xuc tae la ZnO, nhu da dupe M.Lelovsky va A.Kaszonyi bao eao [7] Phan dng duoc tien hanh d 100-140'C ap s u i t kPa, khoang ^ 4-6 gid Ty sd khdi lupng giUa glycerol: urS: c h i t xuc tae la 110:71:3 Hieu suat glycerol carbonat dat dupe % Tang ap suat cao hon, hieu suat giam NHa tao sau phan Ung cd tiie thu hdi va ehuyin hda trd lai thdnh urS Trong [8] cd dUa mpt so dd thidt bj tdng hpp glycerol carbonat tU phan dng gida glycerol va urS nhusau (hinh 2): CIVHC - S 7/2014 NGHIEN CUU - iniG DUNG H2P Hinh So thiet bi tong hgp glycerol carijonate tiJ glycerol va urd Binh phin ting; Diiu chinh ap suat; 3: diiu chinh nhiet do; May khuiy ca hgc; Binh ehOa dau dS dun ndng va Tach amoniac d6 ehlnh ap sud't ve gia tri ap sua't khoing 40 mbar Da tien hanh phan dng gida glycerol vd urS thidt bj tren day (hinh 2) d nhiSt dd 150°C, ty IS mol urS/ glycerol = 1, va ty le trpng lupng chat xde tae/ glycerol = 0,086 Trong nhdng dieu kien dd, da s d dyng c h i t xdc tac la nhdng mudi sulfat kim loai khao Hidu suat san p h l m thay ddi theo ban chat cae chat xdc tac: MnS04: 73%; MgS04: % ; ZnS04: 83%; dung c h i t xdc tae IP mudi kem cda acid p-toluen sulfuric, thi thu dupe hieu sua't glycerol carbonat Id 85% Khi chat xde tae la nhya Bayer Lewatit VP OC da trao ddi vdi ion Zn^*, thi hidu s u i t glycerol carbonat dat dupe % Cung s d d u n g so dd thldt bj nhutrSn (hinh 2), nhUng EP 0955298 A l [9] lai cho biet r i n g dung c h i t xdc tae la MnS04 da nung b 450°C cho phdn Ung glda glycerol va urS d 150''C, thi hieu sua't glycerol carbonat dat dupe 73%, cdn klii ddng chat xde tae IP p-toluen SOs- Zn(OH) cho phan Ung tren b 145°C, thi hieu suat glycerol carbonate ed t h i dat 85% Chat xde tac y-Zr-phosphat dUpe ap dung cho phan dng gida glycerol va urd [10] C h i t xdc tac ndy dupc che tao b i n g phuong phap kS't tda qua phan dng giiJa dung djch nude eda CNHC - S 7/2014 ZrOClz.SHzO va NaH2P04.H20 K i t tda k i t tinh dupe rda b i n g HCI de loai Na' va b i n g nude c i t de loai Cl" Sau dd, k i t tda duoc ldm khd d 25°C khdng khf cd mat PzOs DS sd dyng e h l t xde tac cho phan dng gida glycerol va ure vdi ty Id mol glycerol/ urS = 1,72, d 145''C va ap s u i t kPa ed ket hpp sd dyng dung mdi hda tan lua ehpn glycerol carbonat, vf du acetonitril de c h i l t san p h l m Sau tien hanh phan dng nhdng dieu kien tren day, hon hpp phan dng dupe de ngudi xudng nhiet dp phdng va chiet glycerol carbonat bang dung mdi acetonitril Dung dieh acetonitril dupc tdeh vd lai bd sung them ure vao pha glycerol edn lai d l tien hPnh p h i n dng tiep thdm gid b 145''C, rot lai chiet glycerol carbonat b i n g acetonitril Tap hpp dieh chiet vd cho dung mdi bay hoi ^ong e h l n khdng b nhiet dp phong (27°C) K i t qua thu duoc hieu suat glycerol carbonat t i n g ePng la 90-96%' Vai trd cda ehat xuc tae ZrP eung dUpc nghien cdu edng trinh eda Michele Aresta va ddng tae gia [11] Theo cac tde gia nay, c h i t xdc tac ran cd cau true nhu sau (hinh 3): NGHIEN CUU - UNG DUNG Os^: Hinh Cau trde cda y-ZrP Cd the t h I y e l u tnie Idp cda vat lieu y-ZrP tinh the Khoang each glda hai Idp dtigc xae djnh bang cac nhdm OH phosphat va cae phan td nude va vao khoang 12.25 doi vdi y-ZrP va 9,8 ddi vdi Y-ZrP Trong khoang each gida cac ldp cda y-ZrP ed t h i chdn vao eac cation hdu eo, ion kim loai va eae phde cda kim loai va chdng tUOng tae bang lien ke't hydrogen vdi cac nhdm P-O hay P-OH Khi sddung c h i t xdc tae y-ZrP da nung trUde d 773 K gid de tidn hanh phan Ung giUa glycerol va urS vdi ty IS mol 1/1 va ty IS trpng lupng glycerol/ c h i t xilc tac b i n g khoang 17, d ap suat 20 Pa va nhiet dp 418 K gid da nhan dupe hlSu sudt glycerol carbonate IP 76% Trong [12,13] eung da t i l n hanh phan dng tao glycerol carbonate tU glycerol va ure Phan Ung dUpe thye hien b 120''C, ed mat chat xue tae ia MgS04 khan Ty IS trpng lupng glycerol/ c h i t xde tae = 9,2 Trong nhdng dieu kien nhu vdy, mUc chuyin hPa glycerol la 72% vd dp lua chpn ddi vdi glycerol carbonat IP 92% Chat xde tae C0304/ZnO dupe tao tU eae hat CO3O4 kieh thude nano (40-50 nm) phdn tan tren cac vl hat ZnO (0,2-1 |im) da dagc F.Rubio-Mareos va ddng tae gia sddung eho phan Ung giij'a glycerol va ure de tao thdnh glycerol carbonat [14] Khi t i l n hanh phan Ung b nhdng lupng tuong duong mol cda glycerol va ure, d nhiet dp 140-145°C cd khuay 300 vdng/ phdt, d ap sua't thudng, khdng ddng dung mdl va dung ddng khdng d l d l y NHa khoi vdng phan Ung da thu dagc mUc dp ehuyen hda glycerol la 69% va dp lya ehpn eda glycerol carbonat la 97% Nhu vay, hieu suat glycerol carbonat ed giam mdt chdt so vdi dung ehat xde tae khae De giai thieh dieu dd, eac tae gia dtia sd p h i n Ung gdm bdn giai doan nhU sau (so tren hinh 4): MO J' Hinh So cd ehe phin Ong giiJa glycerol va ure tren ch^t xOe tac COsO^/ZnO: (A) Glycerol uretan; (B) glycerol carbonat; (C) 5-(hydroxymethyl)oxazolidin-2-on; (D) (2-0X0-1,3-dioxolan-4-yl)methyl-earbamat CNHC - S 7/2014 I'l^illJ'l^™""'''! Theo so dd trSn dPy (hinh 4), truPe h i t urS phan Ung vdi glycerol qua phan Ung carbamyl hda (carbamylation) tao thdnh glycerol uretan (A) Giai doan thU hai, c h u y i n hda glycerol uretan glycerol carbonat (4-hydroxymethyl-1,3-dioxolan-2-one) (B) cd tach mpt phan t d NHa, Giai doan thd ba, cijng tu glycerol uretan ed t h i ehuyen hda thPnh 5-(hydroxymethyl)oxazolidin-2-on (C) khPng tach NH3 Glal doan thU tU, glycerol carbonat ed the phan Ung vdi mpt phan td ure khae di tao thPnh (2-oxo-1,3-dloxolan-4yl)-methyl carbamat (D), vd giai doan cd the lam giam hidu suat va dp lua chpn ddi vdi glycerol carbonat lanthan LazOs da dupe dng dung lam chat xde tac eho phan Ung gida glycerol va ure [17] C h i t xue tac dupe dieu ehe b i n g phUPng phap ket tda tU lanthan nitrat b i n g NazCOa vd nung k i t tda La(0H)3 d 600''C Tinh c h i t bazo eda chat xdc tac dupc xae djnh bang phuong giai hap phu theo chuong trinh nhiet dd ddi vdi CO2 (TPD-COz) K i t qua cho thay chat xdc tac LazOa nung d OOO'C cd 74% sd tam bazo manh Chat xdc tac dupe s d dung eho phan dng giUa glycerol va ure vdi ty sd mol glycerol/ urS = b nhiSt dp 140°C va ap s u i t kPa K i t qua eho thay hieu s u i t glycerol carbonat dat , % va dp lya chpn dat 98,6% Phan dng cda glycerol vdi urea cd the xay dung chdt xue tPe titan-silieallt-1 (TS1) [15] Chat xuc tac TS-1 trUdc het dtigc nung gid b 773 K Ty IS mol gida glycerol va ure bdt bang vP ehdt xue tac dUpc dat binh phan Ung He thdng chan khPng (20 Pa) de Ioal va bat gid amoniac thdi gian phan dng dagc ndi vdi dau binh phan Ung Phan Ung dagc t i l n hPnh gid d 418 K k h u l y , sau binh phan Ung dupe IPm ngupi xudng nhiet dp phdng Glycerol carbonat dagc chiet bang CHaCN, ed glycerol vd ure deu khdng tan Dp ehuyen hda glycerol glycerol carbonat b i n g 58% Cdn phan dng ndy dupc thuc hien dung ty le mol glycerol/ urea 1/1, vdi 3% trpng luong chat xde tae, thi dp ehuyen hda glycerol la 36% N l u xuat phat tUty IS mol glycerol/urea : , urS dtigc daa cham gid eho den dat dagc ty le 1/1 M, hiSu sua't c h u y i n hda glycerol dupe dieu k h i l n den gan b i n g % vdi iga ehpn 100% C h i t xde tac ed eau trde hydrotaleit eung da dtigc nghiSn cUu s d dung eho phan dng gida glycerol vPurS [18], Chat xdc tae hydrotaleit kem - nhom ed ty IS mol Zn/AI bang cd ehUa anion sulfat gida cac ldp Chat xde tae dupe tdng hpp bang ddng k i t tda d nhiet dp phdng Chat xdc tPc dtigc xae djnh tinh acid bang phUOng phap phPn tich nhiet trpng lUPng (TGA) dol vdi n-butylamin hap phy hoa hpe va k i t qua cho t h I y vat lieu eo dp acid trung binh Phan dng gida glycerol va urS d nhiet dp UO-C, ty le mol glycerol/ urS = 1:1,05 va lUpng xdc tae la 5% trpng lupng K i t qua thu dupe chuyen hoa glycerol la 93,48% va dp lya ehpn dol vdi glycerol carbonat dat 98,50% Khi s d dung ehdt xue tPe Au mang trSn MgO (2,5% A u / MgO) ed thd thu dUpc hiSu suat glycerol carbonat % gid phan dng vd c h i t xdc tac khdng mat hoat tfnh sau 10 vdng tai s d d u n g [16] C h i t xdc tae bazo ran dudi dang oxide CNHC - s d 7/2014 Gan day nhat, eae nhP nghlSn edu Nhat Ban- Shin-Ichiro Fujita va ddng tac gia [19] da nghiSn cUu eae chat xdc tac ran ehda Zn cho phan dng tdng hpp glycerol carbonat tU glycerol va ure va da chdng minh rang phan dng xay theo eon dUdng ddng the Cac chat xdc tde n h u Z n O , oxide hon hpp SiOz.ZnO hay Alz03.ZnO dieu kien phan Ung ed mpt ea glycerol va ure d 130''C, thi mpt s d Zn^* tan vao hon hpp phan dng va chfnh dang kem ndy ddng vai trd la nhdng tam xue tae theo so dd sau day (so dd trSn hinh 5): 'J!IIJ!iai,IMi„l|J,IIHIA Hinh Sa ca che phin dng giiJa glycerol va ure cd mdt chat xue tac ehda Zn Theo so dd tren (hinh 5), tnrde h i t ZnO phan Ung vpi acid isocyanlc dUpc phat sinh tU urS, di tao phde 1, phde hai phan td NHa phd'i trf yeu Mpt phPn td NH3 phdi tri ed t h i trao ddi vdi mdt phan td glycerol de tao thdnh phde 2, phde nay, phan td glycerol tuong tac vdi tam Zn qua nguySn td oxygen eda nd NhUng roi nhdm hydroxyl tuong tae lai b i t giu" nhdm isocyanate lan can de tao phUe carbamat Nhdm carbamat phdi tri ve sau ehuyen hda thPnh glycerol carbonat qua ddng vdng, cd tach mdt phan td NH3 va tai sinh phde Cung ed the la, sU phdi tri yeu cua glycerol (phde 2) va nhdm carbamat (phde 3) vdi tam Zn qua eac nguyen td oxygen cda eae nhdm hydroxyl lam eho chdng boat ddng hon va dUa den tao kem glyeerolat (C3HB03Zn) qua viec tao phUe Dang hop e h l t eua Zn cd the lang dpng ISn be mat chat xuc tae ban dau va qua trinh xdc tPc lai dupe tiep dien.Trong thuc nghiSm da theo doi dupe lUpng nhd ion Zn tan (C X, X H , hon hpp phan dng, nhimg cho mdc dp ehuyen hda glycerol eao (81-88%) vP dd lya chpn ddi vdi glycerol carbonat cao (74-86%) Nhuvay, hudng tong hop glycerol carbonat qua phan Ung gida glycerol vp ure thu hdt nhieu s u quan tam, kha nang s d dung nhdng nguySn lieu cd san va re tien Tuy nhiSn, phan Ung xay d i i u kiSn ap s u i t thap, van eon la mpt dieu can can nhac hoan thiSn them trien khai d quy md ldn PHAN CfNG GlCfA GLYCEROL VA DIMETHYL CARBONAT Glycerol cd t h i ehuyin hoa thdnh glycerol carbonat bang phan Cmg chuyen ddi este hoa bang dimethyl carbonat Dimethyl carbonat (DMC) Id mpt san p h l m thuong mai, hay ed the tdng hpp dupe t d methanol vd COz Phan dng gida glycerol va dimethyl carbonat (DMC) ed the trien khai san xuat b quy md edng nghiep Phan Ung xay theo phuong trinh sau: on -CHjOH dimethyl carbonate glycerol °Cl^.O glycerol carbonate CNHC - SO 7/2014 EBMBSB Day la mpt qua trinh ed y nghTa cPng nghiep, nen da dupe nghien edu ehi t e t Sau dSy tap tmng khao sat hai loai chat xue tPe cd triln vpng dhg dung cho qua trinh tdng hpp glycerol cartwnat tU glycerol vP DMC cP the triln khai san xuat quy md ldn, la xdc tae bazo va xue tac sinh hpc 4.1 XOc tde bazd Cdc c h i t xdc tae bazo da dade JosP R.Ochoa-GPmez vp dong tac gia nghiSn cdu ehi tilt [20], bao gdm cac oxid klm loai kiem thd (CaO, MgO) Qua trinh phan Ung gida DMC (tinh khilt) va glycerol (tinh khilt) dUOc trdn binh thuy tinh ba cd day trdn cd lap may khuay tU, sinh han hdi luu, cda lay mau vp nhiet ke Hon hpp dUpc dun ndng khuay (1000 vPng/ phdt) d i n nhiet dp mong mud'n vP sau dd chift xdc tac dupc dua vPo de b i t dau phan dng Sau thPI gian phan dng 90 phdt, c h i t xuc tac dupe Ipc va njfa bang methanol lan moi lan 100 mL Dich Ipc dupe tap hpp lai va cho bay hoi tren may eP quay de tach DMC vP methanol khoi san p h l m P h i n dUdupc ed lai de phan tich mUc dp chuyin hoa glycerol vp hiSu s u i t glycerol cartsonaL Theo quy trinh do, ed t h i t i l n hanh thue nghiSm b nhiet (90°C dudi ap suit ty sinh, sd dyng binh phan dng Pan ap suit cao bang thpp klidng gi t h i tfch 300 mL, cd l i p mPy khuly cO hpc, bp phan gia nhiSt bing dien vP bd phan kiem tra nhiet dd tti dpng Nhu eP the nhan thIy tU thyc nghiem tde dp phan Ung chju tac dpng nhieu tU nhiSt dp ddi vdi ca hai loai chat xuc tac Nhiet dp cang cao thi dp chuyen hop va hieu suit eang cao, vp thu dupc dp chuyen hoa 100% va hiSu suit 100% d 75=C ddi vdi xuc tae dong t h i eung nhu eac gia tri cao hon 90% ddi vdi nhdng chat xuc tae di thi Chuyin hoa thap hdn 10% thu dupc d nhiSt dp phdng nhiet dp 75''C dp chuyen hoa va hieu suit dat gia trj cao: tren 90% ddi vdi mdt s i chat xde tae dj the (Cao nung) va tren 98% ddi vdi cac d i l t xuc tac ddng the Dieu cho thIy phan dng ehuyen ddi este hoa xdc tac bazo khong phdi IP phan dng can bing va eo che phan Cihg xay qua anion aleoxid nhutren so tren hinh HO'^Y^S + SH (1) ,pcH3 HO'"Y^§ CH3O" (OCH3 (2) dimethyl carbonate CHjOH CHjOH Hinh Ca chS phin dng chuyin Giai doan dau tien Id phan dng giu^ proton acid y l u eda mdt hai nhdm hydroxyl bac nhat eda glycerol vd chat xde tae bazd de tao anion glyceroxid, vd acid liSn hpp (BH) eda bazo Khi ehd y den dp acid thIp eda nhdm hydroxyl, thi can cd mpt bazo manh giai CNHC - SO 7^2014 doi este hda xuc tac baza B: la baza doan Trong giai doan thd hai, anion glyceroxid tan edng cacbon carbonyl eua phPn td DMC dan den tao hop chat tmng gian methyl glyceryl carbonat cdng vdi anion methoxiL no phan dng vdi acid lien hpp baza (BH) da tao thdnh d giai doan dau tidn, tao '!IIJ"^"W"'I'''III'I'^ methanol vd tal sinh bazo (giai doan 3) Cudi cung, b giai doan bdn, methyl glyceryl carbonat chiu phan dhg vdng hoa qua t i n cdng nhan eda oxygen tU nhdm hydroxyl thU hal vPo cartoon carbonyl de tao thPnh glycerol carisonat vd methanol Cac chat xde tae baza ddng t h i (KOH, NaOH) dan den dp chuyen hop vP hiSu s u i t g i n 100% d 75°C eho thay rang vdi nhdng ehlt xdc tae dd thdi gian phan Ung ngan la dd ma khong lam giam dp ehuyen hoa va hieu s u i t IP thieh hpp theo quan diem cdng nghlSp Tuy nhien, cac chat xde tPc dong the k i l m hydroxid dan den nhdng van de quy trinh tach c h i t xdc tac hoa tan khoi san p h l m Trong trudng hpp san xuat biodiesel, phai dung lupng Idn nude de njfa hydroxid kiem hoa tan khdi san phlm Trong trUdng hpp tdng hpp glycerol carbonat, khong phai sd dyng nude, vi ca hai hpp c h i t deu trpn lan, cdng khd khPn hon viSc tach eha't xue tac hoP tan Theo quan diem dd, eae chat xue tac ddng the trd ndn nPng ne va ehdng can tranh, neu ed the Dd'i vdi cac e h l t xde tac di the, dp chuyen hoa va hieu s u i t thay ddi rdng b JS'C td 95% cung vdi quy trinh tach vP t'nh c h l glycerol carbonat don gian va re tien da dupe nhan dang, eho thay tinh kha thi edng nghiSp eda quy trinh tdng hpp Hon nda, nghiSn eUu tdi Uu hoa ed ehd y den quay vdng chat xde tae s d dyng cac ehlt xde tPc khae va tach MeOH va DMC cho viSc quay vdng d giai doan sau Mpt kha nang d l tranh nhdng van de ddi vdi viec quay vPng CaO phan dng IP thay the ealei dlglyeeroxld eho CaO Phd hpp vdl nhung ket qua trSn dPy, bao eao eda Jose R.Oehoa-Gdmez va ddng tac gia [21] da xem viec dng dyng chat xde tae CaO cho phan Ung giOa glycerol va dimethyl carbonat la phuong an kha thi ve mpt cOng nghiep de san xuat glycerol cariDonat Co the tang hoat dp xdc tac CaO doi vdi qua trinh tdng hpp glycerol carbonat tU glycerol vP DMC mang len CaO mpt lUpng nhd LiOH hay LiCI Khi dd, hieu s u i t glycerol cariDonat cd the dat den 95-97%, dieu kien dun hdi lull d ap sua't thudngfe-ong9 gid [22] Khi nghien eUu kha nang xdc tac eda CaO ddi vdi phan Ung gida glycerol va DMC, F.S Hubertson Simanjuntak vp ddng tae gia [23] da phan lap dupe hpp chat ed dang Ca(C3H763)(Oc62CHa) va dUpc xem la mdt hpp chat tmng gian boat ddng eda phan dng ehuyen ddi este hda eda DMC vdi glycerol TU dd, eac tac gia de nghj so co che phan Ung tao glycerol carbonat nhusau (hinh 7): »(KJK^- »o^J^i^,.,ji>-c»-cr\ir'''y^