CATIONIC POLYMERIZATION OF ISOBUTYLENE COINITIATED BY AICI_3 IN THE PRESENCE OF ETHYL BENZOATE

The cationic polymerizations of isobutylene （IB） coinitiated by AlCl3 were carried out in solvent mixture of nhexane/methylene dichloride （n-hex/CH2Cl2） of 60/40 V/V in the presence of ethyl benzoate （EB） at various temperatures range from -80℃ to -30℃. The effects of EB concentration （[EB]） and polymerization temperature on monomer conversion, weight-average molecular weight （Mw） and molecular weight distribution （MWD, Mw/Mn） of polyisobutylene （PIB） products were investigated. The rate of polymerization decreased while Mw of PIB products increased with increasing [EB]. The polymers with high molecular weight could be prepared in the presence of a suitable amount of EB. Significantly, the polymers with high Mw of 80.2 × 10^4 and 65.4 × 10^4 could be produced at -80℃ and -70℃ at [EB] = 0.24 × 10^3 mol/L respectively, which were much higher than that （Mw = 57.9 × 10^4） of PIB prepared at -100℃ in the absence ofEB. A simple but effective method for preparing the high molecular weight polyisobutylenes was developed in this work. It has been also found that the activation energy for propagation （Ep） depended on the polymerization temperature range in the presence of EB. An obvious inflection of the linear plots of lnXn versus 1/Tp occurred at the temperature range from -60℃ to -50℃ at four different concentrations of EB from 0.19 × 10^3 mol/L to 0.33× 10^3 tool/L, and thus the inflection temperature （Tinf） was in the range of -60℃ to -50℃. When [EB] was in the range of 0.24 × 10^3 mol/L to 0.33× 10^3 mol/L, Ep was determined to be around -12 kJ/mol when the polymerization was carried out at temperatures from -80℃ to Tinf and to be around -28 kJ/mol at temperatures from Tinf to -15℃ respectively.

Selective Oxidation of Isobutylene over Cs-promoted Mo-Bi-Co-Fe-Ce-O Catalyst

Cs-promoted Mo-Bi-Co-Fe-Ce-O catalyst for the selective oxidation of isobutylene to methacrolein had been studied in a fixed bed micro-reactor. The selectivity to methacrolein was significantly improved by the addition of Cs, which could probably enhance the dehydrogenation ability and weaken the oxygenation ability of the catalyst based on temperature programmed reduction （TPR） analysis investigation. The kinetic studies indicated that the oxidation of isobutylene to methacrolein followed the first-order kinetic behavior.

Thermodynamic study of direct amination of isobutylene to tert-butylamine

On basis of thermodynamic empirical equations, the thermodynamic parameters for the direct amination of isobutylene to tert‐butylamine, an atomically economic and green chemical reaction,were calculated. In particular, the equilibrium conversion of isobutylene under various reactionconditions close to those used in industry was calculated and discussed. Isobutylene amination is atemperature sensitive reaction due to its exothermic nature and isobutylene equilibrium conversiondecreases with temperature. However, kinetically, the amination reaction will be faster at ahigher temperature. Thus, there must be an optimum temperature for the reaction. A high pressureand n(NH3)/n(i‐C4H8) molar ratio promote the transformation of isobutylene to tert‐butylamine.Developing a highly efficient catalyst under mild reaction conditions is preferred for the aminationprocess. The reaction was investigated over a series of acidic zeolites. ZSM‐11 zeolite exhibited thebest performance with 14.2% isobutylene conversion (52.2% of the equilibrium conversion) and >99.0% tert‐butylamine selectivity. The effect of reaction conditions on the performance of the ZSM‐11 catalyst agreed with the thermodynamic results, which provides guidance for further catalyst development and reaction condition optimization.

SYNTHESIS OF GRAFT COPOLYMERS WITH POLYISOBUTYLENE BRANCH CHAINS

The copolymerization of 4-vinylbenzyl chloride （VBC） and vinyl acetate （VAC） was carried out in toluene at 75℃ via radical polymerization using 2,2＇-azo-bis-（isobutyronitrile） （AIBN） as an initiator. The random copolymers of poly（4-vinylbenzyl chloride-co-vinyl acetate） （P（VBC-co-VAC）） with number average molecular weight （Mn） from 2000 to 6900, relatively narrow molecular weight distribution （MWD, Mw/Mn ca. 2.0） and with different copolymer composition of 4-vinylbenzyl chloride （VBC） from 17 mol% to 62 mol% could be obtained. The P（VBC-co-VAC） copolymers with an average number of 7 to 13 initiating sites of benzyl chloride per macromolecule could be used for the cationic polymerization of isobutylene （IB）. The cationic polymerizations of IB were further conducted by using P（VBC-co-VAC） copolymers as macroinitiators in conjunction with TICl4 at -40℃ in CH2Cl2. The effects of VBC/TiCl4 （molar ratio） on monomer conversion, Mn and MWD of the resultant copolymers were investigated under 3 sets of conditions. It is found that P（VBC-co-VAC）-g-PIB copolymers with relatively narrow MWD （Mw/Mn ca. 2.0） and with terminal tert-chlorine functional groups in branched PIB chains could be successfully synthesized when VBC/TiCl4 （molar ratio） was set in the range from 0.10 to 1.12. The unimodal GPC curve of the P（VBC-co-VAC）-g-PIB copolymers by RI detector was almost in harmony with the GPC curve by UV detector. The TEM image of the P（VBC-co-VAC）-g-PIB copolymer stained by RuO indicated that the copolymer formed a two-phase morphology with P（VBC-co-VAC）-rich domains of 20-100 um in size tethered by PIB branch segments.

Direct amination of isobutylene over zeolite catalysts with various topologies and acidities

The atomically economic and green chemical reaction of direct amination of isobutylene to tertbutylamine, particularly under the relative mild reaction conditions available for future industrial use,was carried out over zeolite catalysts possessing different topological structures, from one dimensional to three dimensional pore system, and from small 8-member ring pore（MRP） to medium 10 MRP and further to large 12 MRP zeolites, to disclose the relationship between the zeolite properties/topologies and their amination performance systematically under the mild reaction conditions. It was discovered that the pore structure and the acidities of zeolite catalysts played crucial roles in the isobutylene amination process, and suitable pore diameter（larger than 0.5 nm or with large side pockets/cups in the outside surface） and a certain number of mid-strong acid sites are indispensable to catalyze the amination reaction,while too strong acid strength was not conducive to the process of isobutylene amination. Among them,zeolites with topologies of BEA, MFI, MEL, MWW and EUO exhibited good amination performance, with which the isobutylene conversion was higher than 12.61%（>46.42% of the equilibrium conversion） under the studied mild reaction conditions. Due to the good amination performance and the large adjustable Si/Al;ratio range, ZSM-5 was selected to further study the effect of acidity on the amination performance systematically under the mild reaction conditions, and the activity-acidity relationship in the amination process was disclosed: the amination activity（isobutylene conversion） had a linear correlation with the amount of mid-strong B acidity under the studied conditions over ZSM-5 catalyst, which can provide guidance for further developing high-efficient amination catalyst under mild reaction conditions available for future industrial use.

Preparation and Action Mechanism of Inclusion Complex of β-cyclodextrin and Sulfurized Isobutylene as Additives in Solution of Polyethylene Glycol-600

The inclusion complex of β-cyclodextrin (β-CD) and sulfurized isobutylene (T321) was prepared with a co-precipitation method. The tribological properties of the complex with different concentrations were investigated by a four-ball tester in the solution of polyethylene glycol-600 (PEG-600). The experimental results suggest that the complex exhibits better anti-friction and anti-wear properties than β-CD under different load conditions. The tribo-system shows the least friction coefficient when the concentration of the complex is 0.8%. During the friction process, the complex was decomposed into various molecular fragments and the T321 molecules were released onto the friction interface to provide effective lubrication. The XPS analytical results on the worn surfaces reveal that sulfide film formed by the released T321 plays a major role, and the iron alkoxide and carbon deposition films formed by the β-CD fragments have better anti-friction effect on the sulfide film surface. The interactions of different films result in the formation of a mixed boundary lubrication film.

Preparation and Action Mechanism of Inclusion Complex of/%cyelodextrin and Sulfurized Isobutylene as Additives in Solution of Polyethylene Glycol-600

The inclusion complex of fl-cyclodextrin （β-CD） and sulfurized isobutylene （T321） was prepared with a co-precipitation method. The tribological properties of the complex with different concentrations were investigated by a four-ball tester in the solution of polyethylene glycol-600 （PEG-600）. The experimental results suggest that the complex exhibits better anti-friction and anti-wear properties than fl-CD under different load conditions. The tribo-system shows the least friction coefficient when the concentration of the complex is 0.8%. During the friction process, the complex was decomposed into various molecular fragments and the T321 molecules were released onto the friction interface to provide effective lubrication. The XPS analytical results on the worn surfaces reveal that sulfide film formed by the released T321 plays a major role, and the iron alkoxide and carbon deposition films formed by the β-CD fragments have better anti-friction effect on the sulfide film surface. The interactions of different films result in the formation of a mixed boundary lubrication film.

The Project “Development and Application of FCC Additive for Maximization of Propylene and Isobutylene” Passed SINOPEC's Appraisal

The research project'Development and application of FCC additive for maximization of propylene and isobutylene'jointly undertaken by RIPP,the Baling Petrochemical Company(BPC)and the SINOPEC

SYNTHESIS OF HIGH MOLECULAR WEIGHT POLYISOBUTYLENE VIA CATIONIC POLYMERIZATION AT ELEVATED TEMPERATURES

A novel simple but effective initiating system of H2O/AlCl3/veratrole （VE） has been developed to synthesize high molecular weight polyisobutylene （PIB） at elevated temperatures via cationic polymerization of isobutylene （IB） in solvent mixture of hexane/methylene dichloride （n-Hex/CH2Cl2 = 2/1, V/V）. VE played very important roles in decreasing cationicity of the growing chain ends, suppressing side reactions of chain transfer and termination during polymerization, leading to production of high molecular weight PIBs. PIBs with high yields, having very high weight-average molecular weight （Mw） of 1117000 and 370000 g/tool could be synthesized with H2O/AICl3/VE initiating system at VE concentration of 5.4 mmol/L at -80 and -60 ℃ respectively. Molecular weight of PIB increased remarkably with increasing VE concentration. The reaction order with respect to VE concentration was determined to be -3.52 via FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance （ATR） immersion probe. The negative reaction order of VE was consistent with its retarding effect on IB polymerization by interacting with the propagating species. Molecular weight of PIB decreased with increasing polymerization temperature. The activation energy for polymerization degree （Eop） could be determined to be around -23 kJ/mol when VE concentration was 5.4 mmol/L or 6.4 mmol/L.

Functionalized Copolymers of Isobutylene with Vinyl Phenol: Synthesis,Characterization, and Property

The random copolymers of isobutylene (IB) with polar comonomers of 4-acetoxystyrene (ACS) or 4-tert-butoxystyrene (TBO), P(IB-co-ACS) and P(IB-co-TBO), could be successfully synthesized via cationic copolymerization with FeCh-based initiating system. The kinetics of the cationic copolymerization process was in situ investigated by inserting a diamond probe into the reaction system by ATR-FTIR spectroscopy. The chemical structure and incorporation content of polar comonomers in the copolymers were characterized by GPC with RI/UV dual detectors and 1H-NMR spectroscopy. The corresponding functionalized random copolymers of IB with vinyl phenol P(IB-co-POH) carrying phenolic hydroxyl side groups could be further prepared via the complete hydrolysis of acetoxyl side groups in P(IB-co-ACS) or tert-butoxyl side groups in P(IB-co-TBO) copolymers. The functionalized P(IB-co-POH) copolymers became hydrophilic with water contact angle (WCA) of ca. 80° for the self-assembly in hot water, compared to the hydrophobic polyisobutylene with WCA of ca. 110°. The functionalized P(IB-co-POH) copolymers also displayed an excellent self-healing property due to the interaction of intermolecular hydrogen bonding and formation of three dimentional supramolecular networks from phenolic hydroxyl side groups. Furthermore, P(IB-co-POH) copolymers also provided a good matrix for the homogeneous dispersion for silica nanoparticles due to the formation of hydrogen bonding between copolymer chains and silica nanoparticles.

Cationic Polymerization of Isobutylene and C4 Mixed Feed Using Complexes of Lewis Acids with Ethers: A Comparative Study

The cationic polymerization of C4 mixed feed and isobutylene co-initiated by AlCl3xOiPr2,iBuAlC12xnOiPr2, and [emim]Cl- FeCl3xnOiPr2 ([emim]Cl: 1 -ethyl-3-methylimidazolium chloride) has been investigated. AlCl3xOiPr2 co-initiated cationic polymerization of C4 mixed feed proceeds at a lower rate than polymerization of isobutylene affording polymers with higher molecular weight. Complexes of iBuAlCh with di isopropyl ether of different compositions are more suitable co-initiators than AlCl3xOiPr2 for the synthesis of highly reactive polyisobutylene (HR PIB) from C4 mixed feed due to their higher activity in the polymerization as well as possibility to prepare polyisobutylenes with lower molecular weight and higher content of exo-olefin end groups. However, iBuA1C12 needs activating via addition of external water (initiator) and/or interaction with salts hydrates in order to increase the reaction rate and the saturated monomer conversion.[Emim]Cl-FeC13/iPr2O is a quite promising catalyst for the preparation of HR PIB with high exo-olefin end group content (> 80%) and relatively low polydispersity (Mw/Mn < 2.8) via cationic polymerization of C4 mixed feed. The sonication of reaction mixture in case of using [emim]Cl-FeCh allowed increasing the reaction rate and decreasing the molecular weight.

Effect of Phosphoric Acid on HZSM-5 Catalysts for Prins Condensation to Isoprene from Isobutylene and Formaldehyde

A series of HZSM-5 zeolites modified with different amounts of phosphoric acid（P/HZSM-5） was prepared. The physicochemical features of the P/HZSM-5 catalysts were characterized via X-ray diffraction（XRD）, N2 adsorption-desorption, NH3-temperatttre programmed desorption（NH3-TPD） and Fourier tranform infrared（FTIR） spectra of the adsorbed pyridine, and the performances of the catalysts for Prins condensation to isoprene from isobutylene and formaldehyde were investigated. The maximum isobutene conversion and isoprene selectivity were 10.3% and 94.6% on the HZSM-5 catalyst with a Si/A1 molar ratio of 600 using 5%（mass fraction） phosphoric acid. The phosphoric acid modification not only modulated the amount of acidic sites but also regulated the acid type. An appropriate amount of weak Lewis and Bronsted acid sites served as the active sites for the condensation of isobutene with formaldehyde, and the strong acid sites could cause side reactions and coke deposition.

Simulation of Tert-Butyl Alcohol Forming Process by Slurry Catalytic Distillation with Custom Kinetic Program

Producing tert-butyl alcohol (TBA) by slurry catalytic distillation is a green new technology. In order to provide reference data for this production process, this paper applied advanced simulation software Aspen to simulate and optimize the slurry catalytic distillation process of producing TBA. And the kinetics equation of isobutylene hydration which is catalyzed by cation exchange resin in continuous stirred tank reactor (CSTR) is used to display the reaction process. Appropriate theoretical plate number of rectifying section, reaction section and stripping section, reflux ratio and liquid hold-up are obtained by the analog computation. Under this process condition, the conversion rate of isobutylene is 82.53%;the mole fraction of TBA in the bottom discharging is 82.5%.