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《分子催化》2010,(6)
碳酸二苯酯(DPC)是非光气法生产聚碳酸酯(PCs)的重要原料,具有多种酯交换法合成路线,如碳酸二甲酯(DMC)与苯酚酯交换法、DMC与苯基乙酸酯(PA)酯交换法、草酸二甲酯(DMO)与苯酚酯交换法等.本文对比测定了几种金属乙酰丙酮配合物和有机钛化合物对碳酸二甲酯(DMC)与苯基乙酸酯(PA)酯交换合成DPC反应的催化性能,结果表明,乙酰丙酮氧钛[TiO(acac)2]是一种良好的酯交换催化剂,具有优良的催化性能.在反应条件θ=180℃,n(PA)=0.8 mol,n(DMC)/n(PA)=1/2,n(TiO(acac)2)/n(PA)=0.006,t=4 h下,DMC转化率可达74.9%,甲基苯基碳酸酯(MPC)和DPC的选择性分别可达56.9%和38.9%.探索并提出了TiO(acac)2催化DMC与PA酯交换合成DPC反应的机理. 相似文献
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有机钛化合物催化碳酸二甲酯与乙酸苯酯合成碳酸二苯酯 总被引:6,自引:0,他引:6
对比测定了几种有机钛化合物对碳酸二甲酯(DMC)与乙酸苯酯(PA)酯交换合成碳酸二苯酯(DPC)反应的催化性能. 结果表明,乙酰丙酮氧钛(TiO(acac)2)是一种有效的酯交换用催化剂,具有良好的催化性能. 在优化的条件(n(PA)=0.8 mol, n(DMC)/n(PA)=1/2, n(TiO(acac)2)/n(PA)=0.006, θ=180 ℃, t=4 h)下, DMC转化率可达74.9%, DPC和甲基苯基碳酸酯(MPC)的选择性分别可达38.9%和56.9%. 相似文献
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采用分步等体积浸渍法制备了催化剂r%TiO2-q%MoO3/SiO2(1q-r)。以碳酸二甲酯(DMC)与乙酸苯酯(PA)酯交换合成碳酸二苯酯(DPC)为探针反应,考察了1的催化活性。优化反应条件为:PA 290 mmol,n(PA):n(DMC)=2:1,18-4 1.4 g,于180℃反应7 h。在优化反应条件下,DMC转化率77.5%,DPC选择性49.4%,碳酸甲苯酯和DPC的总选择性87.2%。催化剂重复使用时,活性下降很快,也很难通过高温焙烧再生。 相似文献
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乙酸氧钛对碳酸二甲酯与苯酚酯交换的催化作用 总被引:1,自引:0,他引:1
采用溶剂热法合成了乙酸氧钛,其对碳酸二甲酯(DMC)与苯酚的酯交换合成碳酸二苯酯(DPC)的催化反应显示出了很好的催化效果.乙酸氧钛用量0.10 g时,苯酚转化率即达到47.8%,酯交换选择性在99.9%以上,仅检测到微量副产物苯甲醚.傅里叶变换红外光谱(FTIR)和固体核磁共振(13C NMR)等表征结果显示,乙酸氧钛在反应过程中首先与苯酚反应,苯氧基取代乙酸根生成苯氧基钛合物.实验结果表明,苯氧基钛合物作为实际催化剂参与DMC和苯酚的酯交换反应,并且重复使用效果良好. 相似文献
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研究了几种有机钛化合物对草酸二甲酯(DMO)与苯酚酯交换反应的催化性能,发现催化活性及选择性顺序依次为二氯二茂钛钛酸四苯酯钛酸丁酯乙酰丙酮氧钛钛酸乙酯钛酸异丙酯,表明二氯二茂钛是一种性能较好的酯交换催化剂.在n(Cp2TiCl2)=0.001 mol、n(DMO)=0.3 mol、n(Phenol)=0.2 mol、T=180℃、t=2 h优化工艺条件下,苯酚转化率可达44.0%,甲基苯基草酸酯(MPO)和草酸二苯酯(DPO)收率分别达37.8%和6.1%,酯交换总选择性为99.8%. 相似文献
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甲基苯基碳酸酯标准品的制备及其定量分析 总被引:5,自引:0,他引:5
利用甲基苯基碳酸酯(MPC)歧化反应的可逆性及逆反应在热力学上有利进行的特点,提出了以碳酸二甲酯 (DMC)和碳酸二苯酯 (DPC)为原料,在TiO2/SiO2催化下合成DMC与苯酚酯交换反应的中间产物MPC的新方法。反应产物经减压精馏、碱洗、水洗、干燥等精制处理,得到了纯度较高的MPC标准品。采用气相色谱-质谱法对所制备的MPC样品进行定性分析,结果表明其中还含有少量的苯酚和DPC杂质。卡尔·费休水分测定结果表明,MPC样品中的含水量为0.26%(质量分数)。使用常规气相色谱仪,采用OV-101毛细管色谱柱,以苯甲酸乙酯为内标物,对自制的MPC标准品中的微量苯酚和DPC进行定量分析,苯酚和DPC的含量分别为2.04%和1.59%(均为质量分数)。根据杂质分析结果可知自制的MPC标准品的纯度为96.11%。以此作为标准品,解决了对DMC与苯酚酯交换反应的中间产物MPC的准确定量问题。 相似文献
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碳酸二甲酯与苯酚酯交换合成碳酸二苯酯的热力学性质及均相催化剂 总被引:6,自引:0,他引:6
在298.15K,101.325kPa条件下,液态碳酸二甲酯(DMC)的标准Gibbs自由能和熵分别估算为-472.3kJ*mol-1和245.2J*mol-1*K-1.在298K~523K计算了由DMC和苯酚生成碳酸二苯酯(DPC)和苯甲醚反应的热力学性质(ΔrH0m,ΔrS0m,ΔrG0m和平衡常数).计算出的热力学性质表明,DMC和苯酚酯交换合成DPC反应是吸热的,并且在热力学上是不利的.研究了n-Bu2SnO,
Ti(OC4H9)4, AlCl3和ZnCl2四种酯交换法合成DPC反应的催化剂,其中n-Bu2SnO具有最高的催化活性.热力学计算和实验结果均表明,合成DPC反应的最佳温度为453K.当以n-Bu2SnO为催化剂,n(苯酚)∶n(DMC)=4∶1时,DPC的产率和选择性分别为43.0%和88.7%. 相似文献
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A high-purity sample of methyl phenyl carbonate (MPC) was obtained by developing a novel reaction route followed by a series
of separation and purification procedures. Identification and quantification of the MPC sample (98.32%) was performed by a
gas chromatography–mass spectrometry and Karl Fisher titration. The laboratory-prepared MPC was then used as a standard to
optimize quantitative analysis of the products synthesized by transesterification of dimethyl carbonate and phenol. The advantage
of the improved method was that MPC can be quantified directly rather than being calculated by subtracting the yield of diphenyl
carbonate (DPC) and by-product anisole from the conversion of dimethyl carbonate (DMC). The resulting method was validated
for linearity, precision, accuracy, detection limit, and quantification limit. With the improved method, simultaneous accurate
quantification of DMC, MPC, DPC, phenol, and anisole in the transesterification products can be achieved. This enables evaluation
of the activity and selectivity of different catalysts and control of the reaction processes.
相似文献
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Transesterification of dimethyl carbonate with phenol over a bimetallic molybdenum and copper catalyst 总被引:1,自引:0,他引:1
Dongshen Tong Tong Chen Fei Ma Tao Kang Yongcheng Lei Jing Hu Yue Wang Gongying Wang 《Reaction Kinetics and Catalysis Letters》2008,94(1):121-129
Mo-Cu bimetallic oxides were found to be efficient heterogeneous catalysts for the transesterification of dimethyl carbonate
(DMC) with phenol. When the reaction was carried out between 150 and 180°C, with a molar of Mo/Cu of 1:1, molar ratio of phenol/DMC
of 1:1, 4.8 wt.% of the catalyst, 9 h, the conversion of phenol was 49.9%, and the total yield of MPC and DPC was 45.4%. Catalyst
reuse showed a gradual decline in the catalytic activity. The decrease in catalytic activity might be due to leaching out
of Mo and Cu, and/or carbon deposition. 相似文献
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Molybdosphoric Acid Mixed with Titania Used as a Catalyst to Synthesize Diphenyl Carbonate via Transesterification of Dimethyl Carbonate and Phenol
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Tong Chen Huajun Han Zhiping Du Jie Yao Gongying Wang Dachuan Shi Desheng Zhang Zhiming Chen 《天然气化学杂志》2006,15(4):303-306
The 12-molybdosphoric acid mixed with titania (MPA-TiO2) was found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate (DPC) via transesterification of dimethyl carbonate (DMC) and phenol. The X-ray diffraction (XRD) and infrared (IR) techniques were employed to characterize the prepared catalysts. The effect of the weight ratio of the 12-molybdosphoric acid to titania on the transesterification was investigated. A 13.1% yield of DPC and an 11.6% yield of methyl phenyl carbonate (MPC) were obtained over MPA-TiO2 with the weight ratio of MPA to TiO2 as 5:1. 相似文献
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MoO3催化碳酸二甲酯与乙酸苯酯合成碳酸二苯酯 总被引:4,自引:0,他引:4
采用焙烧法制备了MoO3催化剂并将其用于碳酸二甲酯(DMC)与乙酸苯酯(PA)合成碳酸二苯酯(DPC)反应,考察了焙烧温度对催化荆性能的影响,并用X射线衍射(XRD)对催化剂结构进行了表征.结果发现,在400或500℃焙烧的催化剂具有良好的催化性能,DMC转化率为73.9%,DPC和甲基苯基碳酸酯的选择性分别为39.5%和56.5%.XRD结果表明,该催化剂物相组成为正交晶系MoO3,且(021)或/和(110)晶面有利于酯交换反应.催化剂使用5次后DMC转化率从73.9%降至10.2%,多次重复使用后的催化剂在窄气气氛中于400或500℃焙烧即可再生,再生后催化剂的性能几乎和新鲜催化剂相当. 相似文献
15.
Investigation on deactivation cause of lead-zinc double oxide for synthesis of diphenyl carbonate by transesterification
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The deactivation cause of lead-zinc double oxide for synthesis of diphenyl carbonate (DPC) by transesterification of dimethyl carbonate (DMC) with phenol has been investigated.X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),infrared spectroscopy (IR),thermogravimetry analysis (TG),atomic absorption spectroscopy and elementary analysis are employed for the catalyst characterizaton.The results show that,the formation of Pb40(OC6H5)6 through the reaction of phenol and lead species in the catalyst leads to the crystal phase change of active component and serious leaching of lead,which is the cause of the catalyst deactivation.In addition,the composition of the leached lead is ascertained to be a mixture of Pb40(OC6H5)6 and PbO with the weight percentage of 62.7% and 37.3%,respectively. 相似文献
16.
Hyunjoo Lee 《Journal of organometallic chemistry》2004,689(10):1816-1820
Various tin complexes including dibutyltin oxide and dibutyltin diacetate were tested for their activities in the transesterification between dimethyl carbonate (DMC) and phenol to produce diphenyl carbonate (DPC). The activities of tin complexes were significantly enhanced by the co-presence of alkyl or arylsulfonic acid, possibly due to the in situ formation of sulfonate-bonded tin complexes. Highly active triflate-bonded tin species, [Bu2Sn(OH)(OTf)]2 and [Bu2Sn(OAc)(OTf)]2, were isolated from the reaction of triflic acid with dibutyltin oxide and dibutyltin diacetate, and characterized by single crystal X-ray diffraction study. 相似文献
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