气提脱酚制备聚碳级双酚A工艺研究

针对传统的精馏法、结晶法及刮膜蒸发法脱酚工艺存在的诸多弊端,有必要对新的脱酚工艺进行研究,以制备超低游离酚质量分数的聚碳级双酚A。鉴于双酚A-苯酚物系高沸点、热敏性特性,文中以降膜蒸发脱除大部分苯酚、获得的粗双酚A为原料,采用向真空填料塔通入过热水蒸气进行气提的方法,研究制备超低游离酚质量分数聚碳级双酚A的脱酚工艺。研究结果表明:气提塔的操作压力、水蒸气温度和流量对脱酚效果有很大的影响。操作压力越低,组分间相对挥发度增大,脱酚效果越好。但过低的压力对脱酚效果的改善将不明显,带来的负面影响是设备投资的增加;水蒸气温度越高,塔内物料温度也随之升高,苯酚的饱和蒸汽压增大,脱酚效果越好;水蒸气流量越大,在操作压力不变的情况下,苯酚的气相分压就越低,脱酚效果越好。适宜的工艺条件是:操作压力为4.0—5.0 kPa;气提水蒸气温度185—190℃,流量为处理量的2%。     

Thermal degradation of bisphenol A polycarbonate by high-resolution thermogravimetry

Thermal degradation of bisphenol A polycarbonate (PC) has been studied in nitrogen and air from room temperature to 900 °C by high-resolution thermogravimetry (TG) with a variable heating rate in response to changes in the sample's degradation rate. A three-step (in nitrogen) or four-step (in air) degradation process of the PC, which was hardly ever revealed by traditional TG, has been found. The initial thermal degradation temperature of the PC is higher in nitrogen than in air, but the three kinetic parameters (activation energy E, decomposition order n, frequency factor Z) of the major degradation process are slightly lower in nitrogen. The average E, n and lnZ values determined by three methods in nitrogen are 154 KJ mol⁻¹, 0.8 and 21 min⁻¹, respectively, which are almost the same as those calculated by traditional TG measurements. © 1999 Society of Chemical Industry     

Physical aging of bisphenol A polycarbonate

The physical aging of bisphenol A polycarbonate was studied using the differential scanning calorimetry technique. Cowie and Ferguson's model and Williams‐Watts function were used to analyze the data. It is confirmed that the relation ΔH_∞(T_a) = ΔC_p(T_g − T_a), where ΔH_∞(T_a) is the value of the aging enthalpy for t = ∞, T_a the aging temperature, and ΔC_p the difference in the specific heat above and below the glass transition temperature (T_g), can be used to study quantitatively the physical aging of bisphenol A polycarbonate. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1646–1648, 1999     

双酚A下游产品应用市场分析

综述了双酚A在环氧树脂、聚碳酸酯和阻燃剂中的应用、国内外产能及消费需求变化,分析了双酚A下游产品的市场发展趋势及最新动态。     

Mineralization of bisphenol A by advanced oxidation processes

BACKGROUND: Endocrine disruptors, as in the case of bisphenol A (BPA), are increasingly found in aqueous effluents. The degree of mineralization of a bisphenol A (BPA) aqueous solution after applying several oxidation treatments has been investigated. RESULTS: UV‐C photolysis of BPA allowed calculation of the quantum yield, ϕ_λ=254 = 0.045 ± 0.005 mol Einstein⁻¹ but only 15% of the initial organic carbon content (TOC) was eliminated. Better results (80% conversion) were obtained after TiO₂ addition. Ozone inmediately reacts with BPA. Again, TiO₂ addition in the presence of O₃ was capable of increasing the mineralization level (60%). The photolytic ozonation of BPA was capable of completely eliminating TOC. The presence of activated carbon in the O₃/UV and O₃/UV/TiO₂ systems significantly enhanced the TOC removal reaction rate (100% conversion in 20 min). CONCLUSIONS: Processes such as ozonation or photolysis are capable of efficiently removing BPA from water however, mineralization levels are rather low. Addition of TiO₂ to O₃ or UV‐C significantly enhances TOC removal. The remaining organics still account for an average 20–40% of the initial organic carbon. The combination of O₃/UV‐C is capable of completely mineralizing BPA. Activated carbon and/or TiO₂ addition to the system O₃/UV‐C improves the TOC depletion rate. Copyright © 2008 Society of Chemical Industry     

Electrospinning fabrication of partially crystalline bisphenol A polycarbonate nanofibers: The effects of molecular motion and conformation in solutions

Partially crystalline bisphenol A polycarbonate (BPAPC) nanofibers were successfully fabricated using a combination of a centrifugal field (1800 rpm) and an electrostatic field (25 kV). The BPAPC solution properties are key factors for adequately electrospinning the partially crystalline BPAPC nanofibers. The correlation times (τ_c) of methyl (τ_c = 9.3 ns) and of benzene-ring (τ_c = 15.3 and 15.8 ns) motions in the 14 wt.% BPAPC/THF solution were longer than in CH₂Cl₂ and CHCl₃, as determined by NMR. The distribution-peak maximum of the hydrodynamic radius of BPAPC in the 14 wt.% THF solution (R_h = 15 Å) was higher than in CH₂Cl₂ (R_h = 9.2 Å) and CHCl₃ (R_h = 7.9 Å), as evidenced by DLS data. We conclude that the BPAPC assumed a denser, more worm-like chain conformation in THF solvation.     

气相色谱-质谱法测定聚碳酸酯树脂及其成型品中的双酚A

建立了聚碳酸酯树脂及其成型品中双酚A（BPA）的气相色谱-质谱联用（GC—MS）检测方法。样品经丙酮提取后挥发至干,用碳酸钾溶液溶解,再与乙酸酐衍生反应。衍生产物经正已烷提取后,采用GC—MS进行分析。结果表明,方法的线性范围为0．05—1．0mg／L,相关系数为0．9989,线性范围为1．0—10．0mg／L,相关系...     

高级氧化技术降解双酚A的研究进展

对高级氧化技术降解污水中一种内分泌干扰物双酚A（BPA）的作用机理和研究现状进行了综合评述。针对高级氧化技术中最重要的5种技术,即芬顿氧化及光-芬顿氧化、电化学氧化、光分解及光氧化、超声辐射和光催化氧化,详述了各种氧化技术的作用机理、降解效果以及影响因素等。还对这5种高级氧化技术今后可能的发展方向做了初步展望,鉴于各种高级氧化技术降解BPA的条件不同,通过合理设计多种高级氧化技术复合作用并建立优化模型,开发低能耗、高效率以及广泛适用于内分泌干扰物及持久性有机污染物的处理技术。     

Transitions of morphological patterns of crystallizing polycarbonate in thin films

This article reports the transitions of morphological patterns of polycarbonate crystals in thin films by solvent‐induced crystallization (SINC). As a substrate (silica glass) deposited with an amorphous and micron‐thick bisphenol A polycarbonate polymer film is partially dipped into a liquid acetone bath, acetone penetrated rapidly through the polymer film. The rate of acetone penetration is significantly higher than the predicted by Fickian diffusion or anomalous diffusion model, indicating that the capillary force through stress‐induced cracks may have played a major role in the upward transport of acetone through the polymer films. The morphologies of polycarbonate at different vertical positions on a substrate surface were analyzed by scanning electron microscopy and atomic force microscopy. It was observed that depending on the local acetone concentration the polymer morphologies showed quite diverse patterns ranging from stress‐induced cracks to fully developed three‐dimensional spherulites. The diverse morphologies developed during the thin film SINC may serve as a useful platform for further detailed mechanistic analysis of structures and crystallization kinetics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Copolycarbonates derived from bisphenol A phthalates

Blocked copolymers from aliphatic diacids and diol-terminated aromatic polyester blocks have been prepared and studied. The preparations of such block copolymers with good molecular weights proved difficult, but a final carbonation reaction enabled the preparation of materials with values of [η] above 1.0. The mechanical and thermal properties of these have been studied and reported.     

纸塑复合包装材料中化学物迁移的改进预测模型及其通用性

以真实纸塑包装-化学物-食品体系为依据,基于一维Fick扩散理论,考虑化学物在纸和塑料涂层内具有不同的扩散系数及纸的厚度为有限厚,引入纸和塑料涂层界面处的分配系数,给出初始条件和边界条件,建立迁移预测模型,得到解析解。同时,对模型进行简化处理,分析其用于双层同种塑料-化学物-食品体系的使用通用性,并与Laoubi-Vergnaud模型进行对比分析,结果发现所建模型不仅可用于纸塑复合包装材料中化学物的迁移预测,同时还可用于双层同种塑料包装材料中化学物的迁移预测。     

酯交换法合成聚碳酸酯催化剂性能考察

以双酚A和碳酸二苯酯为原料,采用非光气熔融酯交换法合成聚碳酸酯。考察了氢氧化钾、氢氧化钠、四丁基氢氧化铵、碳酸钠、吡啶以及复合催化剂对聚碳酸酯合成反应速率及聚碳酸酯分子量和色差的影响。研究表明,氢氧化钾作为催化剂较适合于聚碳酸酯合成工艺,使用复合催化剂可以得到分子量较高、色差较低的聚碳酸酯。     

Halogen‐free solvent for oxidative carbonylation of bisphenol A to polycarbonate

Halogen‐free solvents for oxidative carbonylation of bisphenol A to polycarbonate using carbon monoxide were investigated. Tetrahydorofuran, γ‐butyrolacton, and acetophenone, which dissolve both bisphenol A and polycarbonate, gave a polycarbonate yield that was lower than using a halogenated solvent of dichloromethane. On the other hand, propylene carbonate that has a carbonate bond gave a polycarbonate yield the same as using dichloromethane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Miscibility of polymer blends of poly(styrene‐co‐4‐hydroxystyrene) with bisphenol‐A polycarbonate

The miscibility of blends of bisphenol‐A polycarbonate (BAPC) and tetramethyl bisphenol‐A polycarbonate (TMPC) with copolymers of poly(styrene‐co‐4‐hydroxystyrene) (PSHS) was studied in this work. It has been demonstrated that BAPC is miscible with PSHS over a region of approximately 45–75 mol % hydroxyl groups in the copolymer. TMPC has a wider miscible window than BAPC when blended with PSHS. The blend miscibility was considered to be driven by the intermolecular attractive interactions between the hydroxyl groups of the PSHS and the π electrons of the aromatic rings of both polycarbonates (PCs). As the FTIR measurements showed, after blending of BAPC with PSHS, there is no visible shift of the carbonyl band of BAPC at 1774 cm⁻¹, whereas the stretching frequency of the free hydroxyl groups of the copoly‐ mers at 3523 cm⁻¹ disappeared. The large positive values of the segment interaction energy density parameter B_st‐HS calculated from the group contribution approach indicated that the intramolecular repulsive interaction may also have played a role in the promotion of the blend miscibility. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 639–646, 1999     

水杨酸双酚A酯的合成与表征

研究了以水杨酸乙酯、双酚A为原料，二丁基氧化锡为催化剂合成水杨酸双酚A醇，考查了催化剂及用量、反应温度、反应时间及物料配比等因素的影响。结果表明：催化剂用量为0．6g，反应温度为120-130℃，反应时间为4h，物料配比为2．10：1，在此条件下，产率在94%以上。产物结构经元素分析、红外光谱、核磁氢谱进行了表征。     

合成双酚A催化剂研究新进展

介绍了用于合成双酚A催化剂离子交换树脂的改性、固体酸催化剂,包括分子筛、杂多酸、自主合成固体酸以及离子液体等新型催化剂;分析比较了它们的催化效果;评述了介孔分子筛、杂多酸、离子液体等催化剂的催化性能和存在的问题,并对未来催化剂的发展提出了建议。     

A calorimetric study of the interchange reactions in bisphenol a polycarbonate/nylon-6 blends

The interchange reactions in a partially miscible blend composed of bisphenol A polycarbonate and nylon-6 have been studied by the use of a calorimetric technique. It has been found that these reactions affect the thermal transitions of the mixtures. These effects have been interpreted to be a consequence of the progressive formation of copolymers which homogenize the mixture.     

A novel solid acid for synthesis of bisphenol A

A novel solid acid was prepared from boric, phosphorous and sulfuric acid by a simple method, and characterized by FT-IR, XRD and TG. Surprisingly, the prepared solid acid is an effective catalyst for the synthesis of bisphenol A from condensation of phenol with acetone. The high conversion of acetone (91.8%) and selectivity of bisphenol A (93.4%) were achieved in the presence of the novel catalyst.     

双酚A反应技术的发展与展望

对双酚Ａ的几种反应技术进行评述,并介绍了近年来的技术发展情况     

塑料食品包装材料化学物迁移的数值模拟

基于有限差分方法数值模拟了塑料食品包装材料化学物向食品（模拟物）的迁移及迁移物在食品内的不稳定性。结果表明,扩散系数DP决定了迁移的动力学过程,分配系数KP,F表征平衡时化学物在包装材料和食品内的浓度比值,平衡时食品内的化学物浓度随化学物在包装材料内的初始浓度Cin的增加而增加。对于多层复合包装,阻隔层可显著减缓污染物层内化学物向食品的迁移,从而达到保证食品安全的目的,阻隔层厚度LR影响阻隔功效。化学迁移物在食品内存在不稳定现象,这将导致实验结果低估其向食品的迁移。