Super-acids supported on ordered mesoporous stuffs, covalently anchored with benzenesulfonic acid, trifluoromethanesulfonic acid or tetrafluoroethanesulfonic acid groups were synthesized. Supported accelerators MCM-41 and SBA-15 were prepared by pore volume impregnation method, utilizing aqueous solutions incorporating 10 wt % benzenesulfonic acid ( BSA ) , 10 wt % trifluoromethanesulfonic acid ( TFA ) and 10 wt % 1,1,2,2-tetrafluoroethanesulfonic acid ( TFESA ) , ensuing six samples. Samples word picture were performed by physical ( X-ray pulverization diffraction, nitrogen adsorption/desorption isotherms and FT-IR spectrometries ) and chemical ( the responsiveness on the glycerin etherification ) methods. Spectroscopic techniques proved successful incorporation of the functional groups. On the same clip, the silicon oxide pure support MCM-41 and SBA-15 were characterized with the same methods, and utilize them like mentions for word picture of those six samples.
Two samples were used in the etherification of glycerin with isobutylene to give tert-butylated derivates. These extremely surface stuffs, with big interrelated mesopores and high handiness of strong acid sites might be suited accelerators for this etherification reaction.
Key-words: silicon oxide, impregnation, wetting agent, etherification.
Super-acids supported on ordered mesoporous stuffs ( OMMs ) or mesoporous molecular screens ( MMSs ) exhibit exceeding chemical and physical belongingss that have suggested a huge figure of applications, such as aromatic alkylation, isomerization, oligomerization, acylation of arenes [ 1, 9 ] . Here we investigate such a catalytic system for the etherification of glycerin with isobutene. Because of the support belongingss such as regular pore construction, high surface country, narrow pore size distribution, adjustable pore size, extremely dispersed active sites and unvarying distribution of these on silicon oxide pore these accelerators are similar to the sulfonic-acid groups incorporated in macroporous ion exchange resins that have been successfully used in such applications [ 2, 5, 9 ] . However, the pore sizes of these mesoporous SBA-15 silicon oxide stuffs are normally less than 10 nanometers, which represents a bound for the separation supermolecules such as proteins and polymers [ 2- 4 ] . MCM-41 has thin walls of formless silicon oxide leting the pore size to be varied from 2 to 10 nanometers, and chemical belongingss can be manipulated [ 3, 5 ] . This silicon oxide s are the ideal template stuff, which permit independent control of both composing and channel size [ 3 ] .
The wetting agent is the most of import on readying process because it defines the construction and porousness of silicon oxide, and the calcination process have the same consequence. The addition in the concatenation length of the wetting agent were found to be effectual in the pore size control in OMMs, including silicon oxide with planar hexangular arrays of cylindrical pores such as MCM-41 templet by alkyl-ammonium wetting agents ( C16 ) , and SBA-15 silicon oxide templet by tri-block copolymers wetting agents ( Pluronic P123 ) , or the usage of fresh wetting agents that form really big micelles [ 4 ] . The usage of wetting agent is one can continuously increase the pore diametre by increasing the sum of the turning agent used.
These silica stuffs functionalized with organosulfonic acid groups have demonstrated an first-class catalytic behavior on the etherification of glycerin with isobutene to give tert-butylated derivates. The usage of reasonably strong acid Centres, such as those located in arene-sulfonic acid modified mesostructured silicon oxide, provides improved consequences both in the glycerin transition and selectivity towards the coveted merchandises [ 6-9 ] .
2.1. Materials used for readying of MCM-41.
The silica synthesis beginnings used were Cab-O-Sil M5 from Sigma Aldrich, tetra-methyl-ammonium silicate ( 15-20 wt % silicon oxide, Sigma Aldrich ) . The CnH2n+1 ( CH3 ) 3NBr ( from Carl Roth ) were used to organize the templet with n=16. The surfactant solution were prepared by ion-exchanging the 20 wt % C16 aqueous solution with equal molar exchange capacity of Amberjet 4400 ( OH ) ion exchange rosin ( Sigma Aldrich ) by 24 Hs batch commixture. The antifoaming agent was Antifoam A Concentrate ( Sigma Aldrich ) , which is a silane polymer alkyl terminated by meth-oxy groups. Acid acetic ( Roth ) was used for pH accommodation of the synthesis solution.
2.2. Materials used for readying of SBA-15.
Poly ( ethyleneglycol ) -block-poly ( propyleneglycol ) -block-poly- ( ethyleneglycol ) ( EO20PO70EO20, Pluronic P123 ) , 1,3,5-trimethylbenzene ( TMB ) and tetraethyl ortho-silicate ( TEOS ) , all from Sigma Aldrich, hydrochloric acid ( HCl ) , potassium chloride ( KCl ) , both merchandises from Carl Roth.
2.3. Common stuffs.
The benzenesulfonic acid ( BSA ) , trifluoromethanesulfonic acid ( Triflic acid or TFA ) and tetrafluoroethanesulfonic acid ( TFESA ) was purchase from Sigma Aldrich. The H2O used in all experiments is de-ionized H2O.
2.4. Catalysts readying of MCM-41.
The surfactant solution was foremost prepared. The pulverization of cetyl-tri-methyl-ammonium bromide ( CTAB, 20.0 g ) was dissolved in de-ionized H2O ( 80.0 g ) to do a 20 wt % solution. These solution mixed by 2 h. Then Amberjet 4400 OH anion-exchange rosin was added into the solution to interchange Br ions with OH ions. The ion-exchange procedure was performed by 24 Hs under vigorous stirring. The ensuing solution was filtered and ready to utilize on the silica readying. The pore diametre fine-tuning is acquired through the alteration in the sum of the wetting agent, the alteration in the continuance of the hydrothermal intervention, the calcination flow type or its calcination temperature.
The fumed silica Cab-O-Sil M5 ( 2.5 g ) was added to the tetra-methyl-ammonium silicate aqueous solution ( 5 g ) and de-ionized H2O ( 55 g ) , so the mixture was stirred smartly for 1 h. Two beads of antifoam agent ( 0.2 wt % of wetting agent ) was added. After this, 28.79 g of the surfactant solution was added under stirring.
Then the pH was adjusted to 11.5 by adding acetic acid under agitation. If the pH of the solution is higher than 11.5, so acetic acid was added drop-wise, else maximal 5 beads of wetting agent was added to set the pH. After 1 H of commixture, the synthesis solution was take it into the polypropene bottle and placed into an sterilizer at 373 K for 6 yearss.
After the solution was cooled to room temperature, the ensuing solid was recovered by filtration ( the remainder over the bottle wall was washed with de-ionized H2O ) , washed in 50 ml de-ionized H2O, filtered once more and dried in an oven at 348 K under ambient air for 24 h. Then the solid was lb really thin, followed by take it in to the glass cell for calcination, with layer thicknesses of the accelerator at 1 centimeter. The pre-dried solid was heated at a changeless rate from room temperature to 813 K over 17 Hs under He flow and keep for 1 H under the same conditions, followed by the calcinations at 813 for 5 H with air to take the residuary wetting agent, so cooled at a changeless rate ( 4 degrees/min ) from 813 K to room temperature under air flow.
2.5. Catalysts readying of SBA-15
The mesoporous SBA-15 silicon oxide atoms were prepared utilizing the tri-block copolymer P123 as a structure-directing agent. In a typical synthesis process, the P123 ( 2.0 g ) and a given sum of the K chloride ( KCl, 1.54 g ) were dissolved in the de-ionized H2O ( 60.0 g ) and hydrochloric acid ( HCl conc.37 % , 11.8 g ) at ambient temperature until the solution became crystalline. Then the 1, 3, 5 trimethylbenzene ( TMB, 1.5 g ) was added to the above solution under stirring. After 10 H of stirring, the tetraethyl ortho-silicate ( TEOS, 4.3 g ) was added drop-wise, and stirred smartly for 30 proceedingss.
The molar ratio of mixture was 1TEOS:0.017P123:0.6TMB:1KCl:5.85HCl:165H2O. The obtained mixture was kept at 348 K in an oven for 24 H, so transferred to an sterilizer and heated under inactive status at 373 K for 24 h. The obtained solid merchandise was filtered ( the remainder over the bottle wall was washed with de-ionized H2O ) , washed in the de-ionized H2O ( 50 milliliter ) , filtered once more and dried at 333 K overnight in an oven.
Removal of organic templet was achieved by heated under air flow status from room temperature to 813 K, with a heating rate of 4 degrees/min, and calcined at 813 K for 10 H under the same conditions, followed by cooled the calcined SBA-15 silicon oxide domains at a changeless rate ( 4 degrees/min ) from 813 K to room temperature.
2.6. Impregnation of silica support with super-acids.
Supported accelerators were prepared by pore volume impregnation method utilizing aqueous solutions incorporating trifluoromethanesulfonic acid ( triflic acid or TFA ) , benzene-sulfonic acid ( BSA ) and 1,1,2,2-tetrafluoroethanesulfonic acid ( TFESA ) . Those silica domains MCM-41 and SBA-15 were impregnated with 10 wt % super-acids. Before impregnation, the surface assimilation capacity of the silica support was checked. Alternatively, the value of the surface assimilation volume from the adsorption-desorption isotherm calculated with BET method could be used. The surface assimilation capacity was checked by the difference between the initial sum of H2O and the sum of H2O staying after surface assimilation.
Adsorption Capacity = V adsorbed H2O = V initial H2O V non-adsorbed H2O.
The resulting mixture ( super-acid and H2O ) was added over silica under uninterrupted stirring for a good and unvarying distribution in the silicon oxide pores. The impregnated silicon oxide was dried nightlong at 373 K in an oven.
2.7. Word picture
Qualifying the pore construction of silica stuffs is of import to look into its physical and chemical belongingss. The liquid N isotherms provide the information to qualify the pore construction of silicon oxide. The typical adsorption/desorbtion isotherms of pure silicon oxide and impregnated silicon oxides follow the type IV isotherm. The surface country can be calculated from the N physic adsorption/desorbtion isotherms by Brunauer-Emmett-Teller ( BET ) methods. Pore volume and pore size distributions can be obtained by Barrett-Joyner-Halenda ( BJH ) methods.
The XRD measuring has an of import application in this article. Although pore walls of silicon oxide are formless, the mesoporous stuff has long-range order as shown in this article, established by the XRD measuring. The two dimensional hexangular construction can be characterized by XRD, demoing a crisp ( 100 ) plane diffraction extremum and besides higher Miller Index diffractions ( 110 ) , ( 200 ) and ( 210 ) . Many research workers have used XRD measurings to qualify nanocrystalline stuffs. The XRD measurings were carried out utilizing a D8 Advance, Bruker X-ray diffract metre ( Cu K? , ? Cu = 1.5406, 40 kilovolt, 40 ma ) .
The FT-IR measurings were done by utilizing a instrument Varian 3100 FT-IR Excalibur Series.
The reaction samples were analyzed by gas chromatography ( Agilent Tehnologies Network GC system ) utilizing a DB- WAX column ( 30 m *0,32 millimeter, DF = 0,32 millimeter ) and a FID sensor.
3. Consequences and treatment
Experience has shown that the equilibrium distribution of adsorbate molecules between the surface of the adsorbent and the gas stage is dependent upon force per unit area, temperature, the nature and country of the adsorbent, and the nature of the adsorbate. An surface assimilation isotherm shows how the sum adsorbed depends upon the equilibrium force per unit area of the gas at changeless temperature.
The silica MCM-41 was prepared utilizing two types of Cab-O-Sil M5, one from the UPG ( ROM ) and the other one from Yale University ( USA ) , utilizing the same method of readying, and the SBA-15 silicon oxide was prepared. The liquid N adsorption/desorption isotherms provide the information to qualify the pore construction of the silicon oxide and look into the pore size, the pore volume and the isotherm type.
The N adsorption/desorption isotherms for the SBA-15 silicon oxide and for the MCM-41 silicon oxide samples prepared with Cab-O-Sil M5 from the Yale University ( USA ) and with Cab-O-Sil M5 from the UPG ( ROM ) are presented in figure 1.
These isotherm are comparable and follow the type IV without hysteresis curves, characteristic for the mesostructured silicon oxide pores with ordinary construction.
The surface assimilation isotherms show four different parts. The first zone at low comparative force per unit area p/p0 ( gaps 0-0.3 for the silica MCM-41 and 0-0.18 for the silica SBA-15 ) is specific to highest nitrogen physical surface assimilation output, associated with a thin-layer adsorbed over silica surface ( at external surface and in mesoporous country ) . The 2nd zone ( gaps 0.3-0.38 for the silica MCM-41 and 0.18-0.2 for the silica SBA-15 ) describe an addition of force per unit area matching to a multi-layer surface assimilation given by the part of the external surface and mesoporous country.
The 3rd zone ( gaps 0.38-0.93 for the silica MCM-41 and 0.2-0.85 for the silica SBA-15 ) reflects the adsorbed nitrogen output turning significantly, that suggest a N cappilar condensation on the mesoporous country. The lowest difference between surface assimilation and desorption curves for pure silica MCM-41 gives an indicant of the pore diametre uniformity, without obstructors. But for pure silica SBA-15 the largest difference between these curves suggest a non-uniformity of the pore diametre.
The 4th zone, at rellative force per unit area near to 1, suggests an addition of the volume of adsorbed N associated with nitrogen condensation in the interparticular infinites.
The pore volume and pore size distributions can be obtained by Barrett-Joyner-Halenda ( BJH ) methods. The pore size distributions for the pure silica SBA-15 and for the pure silicon oxide s MCM-41 prepared with Cab-O-Sil M5 from the Yale University ( USA ) and Cab-O-Sil M5 from the UPG ( ROM ) are shown in figure 2.
The two prepared silicon oxides MCM-41 have about the same dimensions of the porousness ( 27 for the silica MCM-41 ROM and 28 for the silica MCM-41 USA ) , besides for the silica SBA-15, the pore size is about 39.
The X-ray diffraction is the best suited for finding of the majority composing. From the symmetricalness and the strengths of the forms we discover whether the stuff is extremely crystalline or non-crystalline ( with formless construction ) .
The X-ray diffraction exhibit several of import belongingss. The first belongings, they signify whether the accelerator, or a constituent of it, is crystalline or non-crystalline. The 2nd belongings, they yield an estimation of the size of the micro-crystallites that may be present on the samples. The 3rd belongings, gives information about the crystalline construction and the unit cell dimensions, penetration into the atomic components of the unit cell.
The XRD measurings for silica MCM-41 prepared with both type of Cab-O-Sil M5 are shown in figure 3. We observe the silicon oxide prepared with Cab-O-Sil M5 from the Yale ( USA ) present a higher strength for the extremums so for the silicon oxide prepared with Cab-O-Sil M5 from the UPG ( ROM ) , that suggest a really good shaping of the construction for the first silicon oxide.
The D100, D110 si D200 extremums coresponding 2? angle 2.5, 4.4 and 4.8 confirm the formless hexangular construction of the support silica MCM-41 as honeycomb type.
The impregnation was done utilizing the silica MCM-41 prepared with Cab-O-Sil M5 from the Yale ( USA ) and the silica SBA-15.
The N adsorption/desorption isotherms for the impregnated silicon oxide SBA-15 samples prepared are shown in figure 4. This three isotherms are symmetrical and folowing the IV type isotherm with a largest hysteresis curve feature for the mesostructured silicon oxide pore dimension with ordinary construction and with lowest obstructor at the pore degree.
The N adsorption/desorption isotherms for the impregnated silicon oxide MCM-41 samples prepared are shown in figure 5. These isotherm are comparable and follow the type IV without hysteresis curves, the lowest difference between surface assimilation and desorption curves for the impregnated silica MCM-41 gives an indicant of the pore diametre uniformity, without obstructors.
The pore size for the impregnated silicon oxide SBA-15 samples are shown in figure 6 and for the impregnated silicon oxide MCM-41 samples are presented in figure 7.
The pore size for those three impregnated silica SBA-15 samples are the same and equal to 38, on the same clip for those three impregnated silica MCM-41 samples are equal to 26, but for pure silica the pore size is biggest. These suggests the impregnation procedure has partly affected the construction of the pure silicon oxide, likely with increasing of walls thickness because of the super-acids grafted on the surface taking to a lessening of the pore size.
The XRD measurings for the impregnated silicon oxide MCM-41 samples and for the impregnated silicon oxide SBA-15 samples are shown in figure 8.
A little displacement of the first diffraction extremum to take down 2? and the lower strength of impregnated silicon oxide compared to the pure silicon oxide is declarative of a lessening in the pore diametre values. The flattening of the extremums coresponding to 2? angle equal to 4.4 and 4.8 confirm some obstructor of the cannular chanels of the pure silicon oxide caused by the impregnation procedure.
The FT-IR spectrometry for the silicon oxide impregnated with super-acids were done to look into if the average chemical bonds bing at the surface of the pure silica support with super-acids. The vibrational spectra of different groups in a molecule give rise to soaking ups at characteristic frequences, because a normal manner of even a really big molecule is frequently dominated by the gesture of a little group of atoms. The strengths of the vibrational sets that can be associated with the gestures of little groups are besides movable between molecules.
Consequently, the molecules in a sample can frequently be identified by analyzing its infrared spectrum and mentioning to a tabular array of characteristic frequences and strengths or to values of chief compounds.
The FT-IR spectra for the impregnated silicon oxide MCM-41 and for the impregnated silicon oxide SBA-15 samples are shown in figure 9.
We see that FT-IR spectra for pure silicon oxide SBA-15 doesn T present sygnificants extremums, merely a simple quiver characteristic to silica at 950 cm-1. The quiver at 1500 cm-1 observed in sample BSA/SBA-15 is characteristic of the phenyl ring and the quiver at 1760 cm-1 is attribute of the phenyl pealing straight bonded to silica. The intense set at 1205-1230 cm-1 is characteristic of the strong bond C-F ( tri-fluoro-methyl ) , whereas the big set at 1023-1075 cm-1 belongs to C-F bonds, besides is present the specific quiver of the Si-F bond at 1340-1380 cm-1, those quivers are present on the FT-IR spectra for TFA/SBA-15 and TFESA/SBA-15 silicon oxide. The sets at 1740 cm-1 found in those three spectra of the impregnated silicon oxide samples are typical of the asymmetric stretching of SO2 medieties and confirm the presence of the sulfonic acid species.
The FT-IR spectra for pure silicon oxide MCM-41 present sygnificants extremums, whereas a simple quiver characteristic to silica at 1059 cm-1. The quiver at 1400 cm-1 observed in sample BSA/MCM-41 is characteristic of the phenyl ring. The FT-IR spectra for TFA/SBA-15 and TFESA/SBA-15 silicon oxide present intense set at 1205-1230 cm-1 is characteristic of the strong bond C-F ( tri-fluoro-methyl ) , whereas the big set at 1023-1058 cm-1 belongs to C-F bonds, besides the presence of the specific quiver of the Si-F bond at 1355-1363 cm-1. The sets at 1735-1740 cm-1 found for those three impregnated silicon oxide samples are typical of the asymmetric stretching of SO2 medieties and confirm the presence of the sulfonic acid species.
The glycerin etherification with isobutene in presence of acerb accelerator to give a mixture of mono- , di- , and tri-tert-butyl glycerin quintessences ( MTBG, DTBG, and TTBG, severally ) was tested with the 10 wt % TFESA/MCM-41 and with the 10 wt % TFESA/SBA-15. This reaction has been normally performed over accelerator surface besides inside of the pore accelerator.
The output on coveted etherification merchandises depends by size of the accessible surface country for the reactants, by pore size, by figure of acerb active site and on the same clip by mass transportation. The porousness of the accelerator must be adequate to let the reactants theodolite to acid active site ( internal diffusion ) , besides the merchandises off the active site to catalyst surface ( external diffusion ) , hence she doesn t affect mass transportation.
These extremely surface stuffs with big interrelated mesopores and high handiness of strong acid sites might be suitable/eligible accelerators for this etherification reaction.
The 1, 1, 2, 2-tetrafluoroethanesulfonic acid ( TFESA ) impregnated over mesoporous silica MCM-41 and SBA-15 are non tested on this reaction of glycerin with isobutene until now. The mesoporous silicon oxide was impregnated with 10 wt % TFESA and I test it in glycerin etherification with isobutene.
This reaction has been performed in a 600 milliliter chromium steel steel Berghoff sterilizer equipped with mechanical stirring. The sterilizer is electrically heated, with automatic temperature control. For all experiments performed the concentration of the accelerator respect the sum of glycerin loaded in the reactor was 4 wt % , the sum of glycerin is 130 g, running for 5 H at 353 K, at isobutene/glycerol molar ratio of 3/1 and without the pH rectification of the glycerin stage. The concentration of the emulsifier in the both reaction mixture was of 0.1 wt % .
The ammonium quaternate salt ( N-Benzyl-N, N di-methyl-N- [ 4- ( 1, 1, 3, 3 tetra-methyl-butyl ) phenoxy-ethoxy-ethyl ] -ammonium chloride or C27H42ClNO2 was added to the reaction mixture as emulsifier. The stirring rate was enhance and maintained at 1200 rot/min and the force per unit area in the reactor was monitored continuously during the whole continuance of each experiment.
The analyses of the reaction merchandises were performed by gas-chromatography, utilizing an instrument from Agilent Technologies with FID sensor, equipped with DB-WAX polar column of 30 m length and 0.32 millimeter inner diameter. The chromatographic column was operated between 40-220 C, with N as bearer gas.
Figure 10 show the glycerin and the isobutene transitions, the outputs to quintessences of the glycerin and the selectivity to quintessences of the isobutene obtained in the presence of the emulsifier over the TFESA/MCM-41 and the TFESA/SBA-15 as accelerators.
The glycerin transitions are about the same for the two instances, but higher with 1 % when the reaction is performed in presence of the TFESA/MCM-41 as accelerator, around 95 % , and the isobutene transition are the same for the utilizing both accelerators, approximately 100 % , because both accelerators present about the same porousness and the pore construction.
The outputs in mono- and di-ethers are 3 % higher for each merchandise, but the output in tri-ether is approximately 4 % smaller when the reaction is performed in presence of the TFESA/MCM-41 accelerator so the instance were is utilizing the TFESA/SBA-15 accelerator ( around18,6 % for the MTBG, 55,5 % for the DTBG and 20 % for the TTBG ) .
A posible account for these consequences is the difference between the pore size for both silicon oxide, that suggest the silica TFESA/SBA-15 with big interrelated mesopores and high handiness who permit a rapid mass transportation of the isobutene to the glycerin stage and doing the isobutene molecules ready to finishing the glycerin transition to tri-ether.
We observe the same distribution of the selectivity for the isobutene to quintessences such we see in the instance of the outputs to quintessences, a 2 % extremely selectivity to the mono- and di-ethers and a smaller selectivity, approximately 2 % , to the tri-ether when is utilizing TFESA/MCM-41 silicon oxide so the selectivity for each merchandises when the reaction is performed in presence of the TFESA/SBA-15 silicon oxide ( about 9 % for the MTBG, 27,5 % for the DTBG and 10 % for the TTBG ) , because of his smaller pore size enchantress non allow a totaly transition to tri-ether, a steric job.
However, the two reagents are really different in nature. The glycerin is the uninterrupted stage, extremely polar and hydrophilic merchandise. But the isobutene is the spread stage, nonionic and hydrophobic compound. So they show low mutual solubility and signifier two liquid stages while in contact.
Hence, the public presentation of the etherification procedure has been proven to be strongly dependent on the mass transportation between the two liquid stages.
These oxygenated compounds or tert-butylated derivates, when incorporated into the standard Diesel fuel, aid to diminishing the sum of the emanations in atoms, hydrocarbons, C monoxide and unregulated aldehydes, cut downing its viscousness, bettering the flash point.
Typical adsorption/desorbtion isotherms of the pure silicon oxide and the impregnated silicon oxide follow the IV type isotherm and feature for the mesostructured silicon oxide pore dimension with ordinary construction. Both silica s are shown, about, the same uniformity of the pore size distribution.
The pore diametre fine-tuning is acquired through the alteration in the sum of the wetting agent, the alteration in the continuance of the hydrothermal intervention, the calcination flow type or its calcination temperature.
The pore size for the pure silicon oxide is bigger so for the impregnated silicon oxide and these suggests, the impregnation procedure has partly affected the construction of the pure silicon oxide, likely with increasing of walls thickness because of the super-acids grafted on the surface taking to a lessening of the pore size.
The MCM-41 silicon oxide prepared with Cab-O-Sil M5 from the Yale ( USA ) present a higher strength for the XRD extremums so silica prepared with Cab-O-Sil M5 from the UPG ( ROM ) , and suggest a really good defining of construction for the first silicon oxide.
The FT-IR spectra show the characteristic quivers of the phenil ring, of the strong bond C-F and of the asymmetric stretching of the SO2 medieties, who confirm the presence of the acid/sulfonic acid species.
The accelerator TFESA/SBA-15 silicon oxide with big interrelated mesopores and high handiness permit a rapid mass transportation of the isobutene to the glycerin stage and doing the isobutene molecules ready to finishing the glycerin transition to tri-ether.
The public presentation of the etherification procedure has been proven to be strongly dependent on the mass transportation between the two liquid stages.
1. Mark A. Harmer, Christopher Junk, Vsevolod Rostovtsev, Liane G. Carcani, Jemma Vickery, Zoe Schnepp, Synthesis and applications of superacids. 1, 1, 2, 2-Tetrafluoroethenesulfonic acid, supported on silicon oxide, Green Chem. , 9, 2007, 30.
2. Antonio S. Araujo, Solange A. Quintella, Ana Carla S.L.S Coutinho, Synthesis monitoring of SBA-15 nanostructured stuffs, Springer Science+Business Media, Adsorption, 15, 2009, p.306.
3. B. Rac, A. Molnar, P. Forgo, M. Mohai, I. Bertoti, A comparative survey of solid sulfonic acid accelerators based on assorted ordered mesoporous silicon oxide stuffs, Journal of Molecular Catalysis A: Chemical, 244, 2006, p.46.
4. Liang Cao, Tiffany Man, Michal Kruk, Synthesis of ultra-large-pore SBA-15 silicon oxide with 2-D hexangular construction utilizing TIMB as micelle expander, Chem. Mater. , Vol. 21, No. 6, 2009, p.1144.
5. Akira Taguchi, Ferdi Sch Thursday, Ordered mesoporous stuffs in contact action, Microporous and mesoporous stuffs, 77, 2005, p.1.
6. J. A. Melero, G. Vicente, G. Morales, M. Paniagua, J.M. Moreno, R. Roldan, A. Ezquerro, C. Perez Acid-catalyzed etherification of bio-glycerol and isobutylene over sulfonic mesostructured silicon oxide, Applied Catalysis A: General, 346, 2008, p.44.
7. V. Mangurilos, D. Bombos, T.Juganaru, I. Bolocan, M. Bombos, D. Ciuparu, Etherification of Glycerol with Isobutene on Amberlyst 35 Ion Exchange Resin Catalyst in Presence of a Cationic Emulsifier, Rev. Chim. ( Bucuresti ) , 60, No. 12, 2009, p. 1338.
8. Peter Atkins, Juan de Paula, Atkins Physical Chemistry 8th edition, 2006.
9. J.M. Thomas, W.J. Thomas, Principles and pattern of Heterogeneous Catalysis, 1996.