Hoạt tính xúc tác của các chất lỏng ion trên cơ sở imidazolium trong phản ứng este hóa axit béo

TAP CHI HOA HOC

DOL 10.15625/0866-7144.2015-0089

T. 53(1)62-67 THANG 2 NAM 2015

HOAT TiNH XUC TAC CUA CAC CHAT L6N G ION TREN CO SCf

IMIDAZOLIUM TRONG PHAN U'NG ESTE HOA AXIT BEO

Pham Thi Nam Binh*, ©ang Thi Thiiy Hanh, Vu Thi Thu Ha, |Mai Tuyen|

Phdng TNTD Quoc gia vi Cong nghe Igc - hda ddu, Vien Hda hgc Cdng nghiep Viet Nam

Din Tda soan 10-10-2014; Chip nhin dang 13-2-2015

Abstract

Several imidazolium-based ionic liquids were prepared and screened as catalysts for the esterification of oleic acid

with methanol. The experimental results showed that both the type of anion and the length of alkyl chain in the cation

have effects on the catalytic activity of ILs. In all of the ILs investigated, l-decyl-3-methylimidazolium hydrogen

sulfate (CiomimHS04) performed the best activity.The esterification of PFAD in the precence of CiomimHS04 was

investigated. This catalyst showed good catalytic under mild conditions, the conversion of PFAD could reach 97.82 %

after the esterification was c'arried out at 65 "C for 4 h, Futhermore, the catalyst could be reused at least 5 times,

showing good operational stability. Thus, C]omimHS04 is a promising catalyst for conversion of high free fatty acid

(FFA) feeds to biodiesel.

Keywords. Ionic liquids, imidazolium, esterification, PFAD.

1. MO DAU

Trong nhihig nam gin diy, chit ldng ion

(IL)vdi vai trd xuc tac cho chuyen hda biodieselda

thu hiit dugc nhieu su quan tam chii y cua cic nha

nghien ciiu. Xuc tae IL cd rit nhieu uu diem vl ky

thuat, cdng nghe nhu hogt tinh cao d dilu kien nhiet

dg, ap suit thudng; thich hgp vdi hiu hit cac logi

nguyen lieu; de tach ra khdi sin pham [1-7]. Hien

nay,phan ldn cac xiic tic IL hogt ddng tot d khoang

nhi?t dg 130-170 °C vdi ham lugng xiic tac dudi 10

% hoac d khoang nhiet do dudi 100 "C vdi ham

lugng xiic tic 20-24% [1-6]. Dilu nay khiln cho gia

thanh cua sin phim blodlesel vin cao, chua dap iing

y8u cau cdng nghiep.

Vdi muc tieu tim ra mgt logi xiic tic cd hogt tinh

cao d khoing nhiet do va ham lugngthip hon, bai

bao nay di vao tdng hgp mdt sd IL va sang Igc hoat

tinh xiic tic cua chung ddi vdi phan iing este hda.

Xuc tic IL tdt nhit dugc sti dung dl tong hgp

biodiesel tir nguyen lieu hdn hgp axit beo phi thai

ciia qua trinh tinh luyen diu cg (PFAD).

2. THUC NGHIEM

budc tinh chi. PFAD (ngudn gdc Calofic, Viet Nam)

cd thanh phan hda hgc dugc trinh bay trong bang 1.

Bdng 1: Thanh phin hda hgc cua PFAD

2.1. Hoa chat va thiet bi

Cac hda chit cd ngudn gdc tii Sigma-Aldrich va

Spectrum China dugc sir dung true tilp, khdng qua

TT

1

2

3

4

5

Axit

Palmitic

Linoleic

Oleic

Stearic

Khac

Ham lirong, %

28,09

18,02

43,47

9,53

0,89

Pho H va "C NMR ciia IL duprc ghi tren may

Brulcer AVANCE-500 MHz va Brulcer AVANCE￾250 MHz. Tinh chat nhiet cua IL dugc nghien ciiu

tren may DTG-60H Shimadzu. ThiSt bj Hanna HI￾8314 pH meter dugc si dung da xac djnh gia tri pH

Clia cac dung dich IL voi n6ng do 0,1M a nhiet do

20 °C.

2.2. Tong hop IL

2.2.1. TdnghcrplL 1-metylimidazolium (HmimX)

Nho gigt dung dich nuoc chua 0,2 moi HX (vdi

X la CI, BF,, CH3SO3 va HSO,) vao 0,2 moi N￾metylimidazol (mim) da dugc lam lanh sin v8 0 "C

trong dieu kien co khuay. Sau do khuSy h6n hgp