“…The speed at which cellulose dissolved was relatively fast in room-temperature SILs with low viscosity due to the high mobility of ions. Furthermore, the room-temperature SILs including [DBNH][CH 3 CH 2 OCH 2 COO] and [DBNH][CH 3 OCH 2 COO] displayed particularly lower viscosity values of 0.008 and 0.381 Pa·s at 20 °C, respectively, as compared to other imidazolium-based ILs (AmimCl: 0.790 Pa·s at 34 °C; BmimCl: 0.750 Pa·s at 25 °C) reported in previous publications. , The viscosity values of [DBNH][CH 3 CH 2 OCH 2 COO] and [DBNH][CH 3 OCH 2 COO] were almost as low as that of 1-ethyl-3-methylimidazolium acetate (EmimAc) . Although EmimAc possessed a little higher cellulose solubility than the above proposed SILs, the synthesis of SILs involved simpler procedures and milder conditions.…”
Twenty-two
superbase-derived ionic liquids (SILs) (16 novel) including
16 1,8-diazabicyclo[5.4.0]undec-7-enium carboxylate (DBU-SILs) and
6 1,5-diazabicyclo[4.3.0]non-5-enium carboxylate (DBN-SILs) were facilely
synthesized by coupling superbase cations with different carboxylic
anions for cellulose dissolution. Systematic investigations revealed
that the combination of the electron-donating groups, small steric
hindrance groups, and short-chain groups in carboxylate anions with
a larger ring in superbase cations facilitated cellulose dissolution.
The regenerated cellulose films produced from seven SILs ([DBUH][CH3CH2OCH2COO], [DBUH][CH3OCH2COO], [DBUH][CH2CHCOO], [DBUH][CH3COO], [DBUH][CH3CH2COO], [DBNH][CH3CH2OCH2COO], and [DBNH][CH3OCH2COO]) with excellent cellulose solubility exhibited similar
chemical structures, a high degree of polymerization, sufficient thermostability,
smooth morphology, and high mechanical strength. Moreover, room-temperature
SILs with low viscosity displayed a promising opportunity for large-scale
production of renewable packaging. Particularly, in addition to hydrogen
bond destruction by the joint action of anions and cations, the interactions
on (200) and (110) crystal planes of cellulose such as intermolecular
hydrogen bonds (O6–H···O3, O6–H···O2, and O2–H···O6) and van der Waals
forces were destroyed preferentially and violently by the SILs. This
work presented an available protocol in designing novel ILs for commercial
processing of cellulose.
“…The speed at which cellulose dissolved was relatively fast in room-temperature SILs with low viscosity due to the high mobility of ions. Furthermore, the room-temperature SILs including [DBNH][CH 3 CH 2 OCH 2 COO] and [DBNH][CH 3 OCH 2 COO] displayed particularly lower viscosity values of 0.008 and 0.381 Pa·s at 20 °C, respectively, as compared to other imidazolium-based ILs (AmimCl: 0.790 Pa·s at 34 °C; BmimCl: 0.750 Pa·s at 25 °C) reported in previous publications. , The viscosity values of [DBNH][CH 3 CH 2 OCH 2 COO] and [DBNH][CH 3 OCH 2 COO] were almost as low as that of 1-ethyl-3-methylimidazolium acetate (EmimAc) . Although EmimAc possessed a little higher cellulose solubility than the above proposed SILs, the synthesis of SILs involved simpler procedures and milder conditions.…”
Twenty-two
superbase-derived ionic liquids (SILs) (16 novel) including
16 1,8-diazabicyclo[5.4.0]undec-7-enium carboxylate (DBU-SILs) and
6 1,5-diazabicyclo[4.3.0]non-5-enium carboxylate (DBN-SILs) were facilely
synthesized by coupling superbase cations with different carboxylic
anions for cellulose dissolution. Systematic investigations revealed
that the combination of the electron-donating groups, small steric
hindrance groups, and short-chain groups in carboxylate anions with
a larger ring in superbase cations facilitated cellulose dissolution.
The regenerated cellulose films produced from seven SILs ([DBUH][CH3CH2OCH2COO], [DBUH][CH3OCH2COO], [DBUH][CH2CHCOO], [DBUH][CH3COO], [DBUH][CH3CH2COO], [DBNH][CH3CH2OCH2COO], and [DBNH][CH3OCH2COO]) with excellent cellulose solubility exhibited similar
chemical structures, a high degree of polymerization, sufficient thermostability,
smooth morphology, and high mechanical strength. Moreover, room-temperature
SILs with low viscosity displayed a promising opportunity for large-scale
production of renewable packaging. Particularly, in addition to hydrogen
bond destruction by the joint action of anions and cations, the interactions
on (200) and (110) crystal planes of cellulose such as intermolecular
hydrogen bonds (O6–H···O3, O6–H···O2, and O2–H···O6) and van der Waals
forces were destroyed preferentially and violently by the SILs. This
work presented an available protocol in designing novel ILs for commercial
processing of cellulose.
“…The activation energy ( E a (kJ/mol)) of the diamine aromatic epoxy pre-polymers were calculated by Eq. (3) 38–40 .where Viscosity ( η ) (Pa.s), η 0 is a constant, R the gas constant (8.314 j/mol.K) and T is temperature in K.Figure 2Viscosity measured as a function of shear for diamine aromatic epoxy pre-polymers DAEP1 and DAEP2 at different temperature.…”
Present study is designed for the synthesis, characterization and corrosion inhibition behavior of two diamine aromatic epoxy pre-polymers (DAEPs) namely, N
1
,N
1
,N
2
,N
2
-tetrakis (oxiran-2-ylmethyl) benzene-1,2-diamine (DAEP1) and 4-methyl-N
1
,N
1
,N
2
,N
2
-tetrakis (oxiran-2-ylmethyl) benzene-1,2-diamine (DAEP2) for carbon steel corrosion in acidic medium. Synthesized DAEPs were characterized using spectral (Nuclear magnetic resonance (
1
H NMR) and Fourier transform infrared-attenuated total reflection (FTIR-ATR)) techniques. Viscosity studies carried out at four different temperatures (20–80 °C) increase in temperature causes significant reduction in their viscosities. The anticorrosive properties of DAEPs differing in the nature of substituents, for carbon steel corrosion in 1 M HCl solution was evaluated using several experimental and computational techniques. Both experimental and computational studies showed that inhibitor (DAEP2) that contains electron releasing methyl (-CH
3
) showed higher protectiveness as compared to the inhibitor (DAEP1) without substituent (-H). Electrochemical results demonstrate that DAEPs act as reasonably good inhibitors for carbon steel in 1 M HCl medium and their effectiveness followed the sequence: DAEP2 (92.9%) > DAEP1 (91.7%). The PDP results show that the diamine aromatic epoxy pre-polymers molecules (DAEPs) act as mixed type inhibitors. Electrochemical study was also supported using scanning electron microscopy (SEM) method were significant improvement in the surface morphology of inhibited (by DAEPs) metallic specimens was obtained. Results derived from computational density functional theory (DFT) and molecular dynamics (MD) simulationsand studies were consistent with the experimental results derived from SEM, EIS and PDP electrochemical studies. Adsorption of the DAEPs obeyed the Langmuir adsorption isotherm model.
“…A decrease in viscosity with a corresponding increase in the shear rate was observed, suggestive of the fact that the epoxy monomer ER/ethanol showed a non-Newtonian rheological behavior of pseudo-plastic type. 42 The viscosity behaviors of epoxy monomer ER/ethanol as a function of shear rate depends on temperature and concentration, respectively. As anticipated, the viscosity of ER increases with increase in ER concentration, primarily resulting from the increase in the molecular interactions between the epoxy monomers (entanglements, see…”
Section: Mechanism Of Epoxide Ring Openingmentioning
confidence: 99%
“…The effect of molecular structure on the value of E a has been reported by many authors. 42 3.3. Electrochemical measurements 3.3.1.…”
Section: Mechanism Of Epoxide Ring Openingmentioning
A new epoxy monomer, namely, tetraglycidyl-1,2-aminobenzamide (ER), was synthesized by condensation of the amines with epichlorohydrin in a basic medium.
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