1075-38-3Relevant articles and documents
Influence of n Si/n Al ratio of HY zeolite catalysts on alkylation of toluene with tert-butanol
Wang, Yuanyuan,Song, Hua,Sun, Xinglong,Song, Hua Lin
, p. 2503 - 2507 (2016)
The highly selective synthesis of 4-tert-butyltoluene from toluene and tert-butanol over HY zeolites was performed in liquid phase. The effect of Si/Al ratio (6.3, 7.5, 11, 12) of HY zeolites on the alkylation performance was studied. The catalysts were characterized by SEM, XRD, FT-IR, and NH3-TPD methods. With increase of Si/Al ratio, the conversion of toluene and the selectivity towards 4-tert-butyltoluene increased gradually. HY-12 was found to be more suitable for the tert-butylation of toluene. When the alkylation reaction was conducted at 180°C for 4 h using HY-12 catalyst, the conversion and the selectivity of 4-tertbutyltoluene reached 40.74 and 70.91%, respectively.
Tert-Butylation of toluene with tert-butyl alcohol over immobilized titanium species on the Al-MCM-48
Zhou, Zhiwei,Mao, Wei,Qin, Juan,Han, Tianpeng,Han, Chaofan,Wu, Wenliang
, p. 132 - 137 (2015)
A series of Ti-Al-M48 (M48 stand for MCM-48) samples with different titanium species loadings were prepared by immobilization method. Their physical chemical properties were characterized by XRD, liquid N2 adsorption-desorption, Py-IR, NH3-TPD and UV-vis DRS techniques, and their catalytic performances were investigated in the tert-butylation of toluene with tert-butyl alcohol in a 100 ml stainless steel autoclave equipped with a magnetically driven impeller. The Ti-Al-M48 samples have a large BET surface and ordered mesoporous structure. Although the titanium species loading is the same, the 4% Ti-Al-M48 sample has a larger acid amount than the 4% Ti/Al-M48 sample prepared by impregnation. The Py-IR and UV-vis DRS spectra revealed that the isolated TiO4 tetrahedra by isomorphous substitution into the Al-M48 network have Lewis acidity. The 4% Ti-Al-M48 has a higher catalytic performance than other samples and the influence of reaction conditions on the tert-butylation of toluene was discussed. The conversion of toluene is 47.5% and the selectivity of p-tert-butyltoluene is 77.2% at the molar ratio of tert-butyl alcohol to toluene 2, the weight ratio of toluene to catalyst 8, reaction temperature 453K and reaction time 4 h. The 4% Ti-Al-M48 sample shows high stability, and toluene conversion 43.7% and p-tert-butyltoluene selectivity 78.4% can be obtained even though after repeated reaction for 3 times.
Tert-butylation of toluene with tert-butanol over transition metal oxide-modified HBEA zeolite
Han, Yixian,Song, Hua,Wang, Yuanyuan,Sun, Xinglong,Sun, Zhigang
, p. 160 - 165 (2018)
A series of transition metal oxide-modified HBEA (MxOy/HBEA) zeolite catalysts were prepared by the wetness impregnation method, and investigated for the alkylation of toluene with tert-butanol to synthesise 4-tert-butyltoluene (4-TBT). Their physico-chemical properties were characterised by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller and NH3 temperature-programmed desorption methods. MxOy/HBEA zeolite showed higher para-selectivity than parent HBEA due to its improved structural and acidic properties. Though the toluene conversion of MxOy/HBEA catalyst decreased, the 4-TBT selectivity increased significantly at 190 °C after 4 h. The narrowed pores after loading the MxOy prompted an increase in selectivity for 4-TBT by increasing the shape selectivity. In addition, the decrease in strong acid sites increased selectivity for 4-TBT by suppressing further isomerisation of the 4-TBT formed on acid sites. Among all the modified HBEA zeolites, Fe2O3/HBEA exhibited the best catalytic activity and para-selectivity. The factors affecting the reaction over Fe2O3/HBEA have also been investigated extensively.
Alkylation of toluene with tert-butyl alcohol over HPW-modified HΒ zeolite
Wang, Yuanyuan,Song, Hua,Sun, Xinglong
, p. 2134 - 2141 (2016)
An Hβ-supported heteropoly acid (H3PW12O40(HPW)/Hβ) catalyst was successfully prepared by wetness impregnation, and investigated in the alkylation of toluene with tert-butyl alcohol for the synthesis of 4-tert-butyltoluene (PTBT). X-ray diffraction, scanning electron microscopy, transmission electron microscopy, fourier-transform infrared spectroscopy, inductively coupled plasma-optical emission spectrometry, the brunauer emmett teller (BET) method, temperature-programmed NH3desorption, and pyridine adsorption infrared spectroscopy were used to characterize the catalyst. The results showed that loading HPW on Hβ effectively increased the B acidity and decreased the pore size of Hβ. The B acidity of HPW/Hβ was 142.97 μmol/g, which is 69.74% higher than that of Hβ (84.23 μmol/g). The catalytic activity of the HPW/Hβ catalyst was much better than that of the parent Hβ zeolite because of its high B acidity. The toluene conversion over HPW/Hβ reached 73.1%, which is much higher than that achieved with Hβ (54.0%). When HPW was loaded on Hβ, the BET surface area of Hβ decreased from 492.5 to 379.6 m2/g, accompanied by a significant decrease in the pore size from 3.90 to 3.17 nm. Shape selectivity can therefore play an important role and increase the product selectivity of the HPW/Hβ catalyst compared with that of the parent Hβ. PTBT (kinetic diameter 0.58 nm) can easily diffuse through the narrowed pores of HPW/Hβ, but 3-tert-butyltoluene (kinetic diameter 0.65 nm) diffusion is restricted because of steric hindrance in these narrow pores. This results in high PTBT selectivity over HPW/Hβ (around 81%). The HPW/Hβ catalyst gave a stable catalytic performance in reusability tests.
A process scheme involving transalkylation reactions to prepare o-bromophenol from phenol
Trivedi, Nikhil R.,Chandalia, Sampatraj B.
, p. 5 - 9 (1999)
The bromination of phenol to o-bromophenol was carried out by protecting the para position with a tert-butyl group. The latter group was subsequently transferred to toluene using aluminum chloride as a catalyst. The resulting mixture of p-and m-tert-butyltoluene could be converted back to p-tert-butylphenol by transalkylation of the former with phenol in the presence of Engelhard, F-24. Thus, a process scheme based on transalkylation reactions as the intermediate steps has been proposed to synthesize o-bromophenol from phenol via p-tert-butylphenol. The effect of reaction parameters on overall conversion to and selectivity with respect to the desired product was studied for the transalkylation reactions involved in the process.
Electrophilic Aromatic Substitution. 10. A Kinetic Study of the Friedel-Crafts tert-Butylation Reaction in Nitromethane
DeHaan, Franklin P.,Chan,Wai H.,Chang, Jeffrey,Ferrara, Daro M.,Wainschel, Larry A.
, p. 1591 - 1593 (1986)
A kinetic study of the reaction between tert-butyl chloride and benzene or toluene using aluminum chloride as catalyst was made in solvent nitromethane over the temperature range -27 to 10 deg C.The rate law was found to be first order in aromatic hydrocarbon, in tert-butyl chloride and in initial catalyst concentration.At -15 deg C k3 for benzene = 6.7 (+/-1.0) * 10-2M-2s-1; for toluene k3 = 20 (+/-2)*10-1M-2s-1 with product isomer percentages meta 4.6 +/- 0.3 and para 95.4 +/- 0.3.Ea is 76 +/- 13 kJ/mol, ΔH = 74 +/- 13 kJ/mol, and ΔS = 16 +/- 46 J/deg mol.Competitive results were kT/kB = 25 +/- 1, 4.9 +/- 0.1percent meta, 95.1 +/- 0.1percent para.The results fit Brown's selectivity relationship.A mechanism involving a rate-determining attack by a tert-butyl cation-AlCl4- ion pair on the aromatic is proposed.
Alkylation of Toluene with tert-Butyl Alcohol over Different Zeolites with the Same Si/Al Ratio
Han, Yixian,Song, Hua,Sun, Xinglong,Wang, Wenyi,Wang, Xueqin,Wang, Yuanyuan,Zhang, Jiaojing
, p. 991 - 997 (2020)
Three zeolites (Beta, Mordenite and ZSM-5), with different pore channels but the same Si/Al ratio (25), were applied as catalysts to evaluate the effects of acidity and channel structure on the catalytic activity for toluene butylation at 180°C in an automated high-pressure stainless steel reactor. The same Si/Al ratio of the three zeolites resulted to different catalytic activity, since both acidity and channel structures of zeolites influenced catalytic activity. Zeolite Beta possessing a three-dimensional, 12-ring channel system, the smallest crystal size and larger amount of B acid sites demonstrated the highest toluene conversion (54percent). Mordenite, with 32.7percent toluene conversion, exhibited higher para-selectivity than Beta, which could be explained by the shape-selective catalysis. ZSM-5 with the largest amount of B acid sites presented the lowest catalytic activity, since alkylation can occur only on the surface active sites.
Preparation of H-mordenite/MCM-48 composite and its catalytic performance in the alkylation of toluene with tert-butanol
Zhou, Zhiwei,Cheng, Fuling,Qin, Juan,Yu, Pengcheng,Xu, Lin,Gu, Zhiqiang,Liu, Xiaoqin,Wu, Wenliang
, p. 1669 - 1675 (2017)
A series of HM/MCM-48 samples with different SiO2/Al2O3 molar ratio were prepared by sol-gel method. The prepared catalysts were characterized by XRD, N2 adsorption-desorption, NH3-TPD, FT-IR, SEM, and TEM techniques, and their catalytic performance was investigated in alkylation of toluene with tert-butanol. The adsorption capacity and the acid sites amount of HM/MCM-48-4 sample prepared by growing MCM-48 on the surface of HM zeolite are much higher than that of their mechanical mixture (HM/MCM-48(4) sample) due to its biporous structure; it shows higher catalytic performance than other HM/MCM-48 samples. The influence of reaction conditions on the catalytic performance of HM/MCM-48-4 zeolite was discussed. Toluene conversion of 41.4% and p-tert-butyltoluene selectivity of 73.5% were obtained at the weight ratio of toluene to HM/MCM-48-4 of 5, reaction temperature of 453 K, reaction time of 5 h and the molar ratio of toluene to tert-butanol of 0.5.
Thermochemical properties of branched alkylsubstituted benzenes
Verevkin, Sergey P.
, p. 1029 - 1040 (1998)
The standard (p○ = 0.1 MPa) molar enthalpies of formation ΔfH○m (1 or cr) at the temperature T = 298.15 K were measured using combustion calorimetry for tert-butylbenzene, 4-methyl-1-tert-butylbenzene, 3,5-dimethyl - tert-butylbenzene, 5-methyl-1,3-di-tert-butylbenzene, and 1,4-di-tert-butylbenzene. The standard molar enthalpies of vaporization Δg1H○m, or sublimation ΔgcrH○m, of these compounds, and also of 3-methyl-1-tert-butylbenzene, 1,3-di-tert-butylbenzene, and 1,3,5-tri-tert-butylbenzene were obtained from the temperature function of the vapour pressure measured in a flow system. Enthalpies of fusion Δ1crH○m of solid compounds were measured by d.s.c. Strain enthalpies of branched alkylbenzenes were derived from the measured enthalpies of formation of the gaseous compounds. These experimental results, together with the data available from the literature, provided a quantitative understanding of the interrelations of structure and energetics of alkylbenzenes, and a further improvement on the group-contribution methodologyfor estimation of thermodynamic properties of organic compounds.
Friedel-Crafts alkylation of toluene with tert-butyl alcohol over Fe2O3-modified Hβ
Wang, Yuanyuan,Song, Hua,Sun, Xinglong
, p. 107239 - 107245 (2016)
Fe2O3 (x)/Hβ catalysts with different Fe2O3 loadings (x) were successfully prepared and characterized by XRD, SEM, TEM, ICP, BET, NH3-TPD and Py-IR. With selective alkylation of toluene with tert-butyl alcohol to produce 4-tert-butyltoluene as a probe reaction, the effects of the different Fe2O3 loadings on channel structures, acidity and catalytic performance over Hβ were studied. The results showed that modification of Hβ with Fe2O3 could adjust pore structures and decrease the total acidity, especially the strong acidity of Hβ. The parent Hβ exhibited the highest toluene conversion of 58.4% with the lowest PTBT selectivity of 67.3%. The low para-selectivity over parent Hβ could be attributed to the low shape-selective action of 12-ring portals of Hβ and the isomerization of the formed PTBT to MTBT. Upon loading of Fe2O3, the toluene conversion of Fe2O3 (x)/Hβ catalysts decreased slightly, but the PTBT selectivity increased significantly. A toluene conversion of 54.7% with PTBT selectivity of 81.5% was observed over Fe2O3 (20%)/Hβ at 190 °C after 4 h. The narrowed pores after loading the Fe2O3 were beneficial to increasing the selectivity to PTBT, since PTBT with a lower kinetic diameter (0.58 nm) can diffuse through the narrowed pores of Fe2O3 (x)/Hβ more easily than MTBT (0.65 nm). In addition, the decrease in number of strong acid sites and deactivation of acid sites on the surface are beneficial to increasing the selectivity to PTBT by suppressing further isomerization of the formed PTBT on acid sites.
