羟基磷灰石晶须的水热制备

羟基磷灰石（HA）晶须具有较低的位错密度,较高的抗拉性能,可掺杂到生物材料中来提高材料的性能。本实验采用氯化钙和磷酸氢二铵的混合物为前躯物,以水为溶剂,以乙酰胺为pH值调节剂,通过水热法制备了结晶度较高、晶粒完整的HA晶须。借助XRD,FT—IR,SEM及TEM分析了HA的晶相组成、化学组成、形貌及大小。     

Molten Salt Synthesis of Calcium Hydroxyapatite Whiskers

Calcium hydroxyapatite (HA) whiskers and crystals were produced by the route of molten salt synthesis. The effects on whisker morphology of chosen flux, flux-to-HA ratio, synthesis temperature, and reaction time were investigated. The thermal stabilities of the produced whiskers were tested at 1300°C in an air atmosphere. A tentative X-ray diffraction pattern was proposed for the HA whiskers. Molten salt synthesis with a K₂SO₄ flux was found to be a simple and sturdy technique for manufacturing short (≤60 μm) HA whiskers in the temperature range from 1080° to ∼1200°C. The alternative use of fluxes such as KCl, KBr, CaCl₂, or Na₂SO₄, rather than K₂SO₄, over the temperature range 850°–1000°C resulted in the formation of large (∼25 μm) single crystals of HA.     

Kinetic Effects on Hydroxyapatite Whiskers Synthesized by the Chelate Decomposition Method

Hydroxyapatite (HA) whiskers have been synthesized using a number of chemical solution methods, including the chelate decomposition method. Numerous previous studies have investigated the effects of the reagents, reagent concentrations, solution pH, and reaction temperature on HA whisker morphology and composition. However, purely kinetic effects, such as the reaction heating and stirring rates, have not been rigorously investigated and are rarely reported in the literature. Therefore, the objective of this study was to investigate kinetic effects on the morphology of HA whiskers synthesized using the chelate decomposition method. In order to study the kinetic effects on the morphology of HA whiskers, three experimental parameters were varied independently: the reaction heating rate (0.36°–3.0°C/min), stirring rate (0–250 rpm), and temperature (80°–200°C). At all heating and stirring rates, precipitated whiskers were confirmed by XRD and FT-IR to comprise phase-pure, calcium-deficient HA (Ca/P=1.57–1.62). The length and aspect ratio of HA whiskers increased with decreased heating rate, decreased stirring rate, and increased reaction temperature. The mean length and aspect ratio of HA whiskers increased approximately twofold with decreased heating rate over the range studied, following a power-law relationship. Therefore, the reaction heating rate is a key variable that can be used to tailor the morphology of HA whiskers and ought to be reported in the literature. The reaction heating rate and temperature had relatively little effect on the width of HA whiskers. However, the precipitate morphology was altered significantly from micro-scale whiskers to nano-scale plates with increased stirring rate. These results offered new insights and provided clarification regarding the reaction mechanism, which is discussed in detail.     

有机溶胶凝胶法制备Al2O3纳米粉及其机理研究

将异丙醇铝分散在有机溶剂中，水解合成超细Al2O3纳米粉。针对纳米粉形成团聚的直接原因，改善了传统工艺，用IR，SEM验证了其合理性，并用TEM对煅烧后的产品进行了表征。     

双组分混合有机溶剂中脂肪酶催化反应的热力学分析

将两种不同极性的有机溶剂1,4-二氧六环和正庚烷按不同摩尔比混合，配成具有不同logP值的双组分混合溶剂，以此为反应介质考察了固定化脂肪酶Lipozyme RM IM催化的正丁醇和月桂酸酯化反应的初速度. 同时在与上述混合溶剂具有相近logP值的单一溶剂中进行了类似研究. 实验结果表明，在混合溶剂和单一溶剂中，反应初速度随溶剂极性的变化规律呈现很大差异. 从溶剂混合对反应物热力学活度及反应活化能的影响可以合理地解释这一实验结果.     

Novel Method for Synthesis of Well-Crystallized Vanadyl(2+) Hydrogen Phosphate Hemihydrate: Crystallization in Organic Media Containing a Small Amount of Water

Vanadyl(2+) hydrogen phosphate hemihydrate (VOHPO₄0.5H₂O, VHP) that had high crystallinity and showed a strong (001) peak in its X-ray diffractometry (XRD) pattern was synthesized via thermal treatment of a mixture of vanadyl(2+) acetylacetonate and triethyl phosphate at 200°C in organic solvents that contained a small amount of water. Scanning electron microscopy observations revealed that the product consisted of thin plates (2-4 µm wide and <0.5 µm thick). When the reaction was conducted at 250°C, a VHP sample was formed that exhibited stronger XRD peaks and had a plate width of >20 µm. The present VHP sample was topotactically transformed to divanadyl(2+) pyrophosphate, which showed a strong (020) XRD peak, via thermal treatment in a nitrogen atmosphere at 500°C.     

有机溶剂中酶多功能性催化有机合成反应

近年来,酶的多功能性广泛应用于有机合成反应.本文综述了有机溶剂中水解酶、氧化还原酶、转移酶和裂解酶催化有机合成反应.     

磷酸酯功能单体的缓释法合成研究

采用溶剂分散P2O5投料方式,缓释法合成了丙烯酸羟丙基磷酸酯的功能单体,研究了分散剂及其用量、反应物料比、反应时间及有无水解反应对磷酸酯中单、双酯含量的影响。结果表明,当分散剂选用正己烷且m（正己烷）：m（P2O5）=4：1,原料配比n（HPA）In（P2O5）=2．4：1,酯化反应温度为70℃,反应时间4h,酯化反应后,达到水解温度再保温10min时,磷酸酯中单、双酯物质的量比值最高。与传统的P2O5粉末直接投料法相比,该方法合成的丙烯酸羟丙基磷酸酯中单酯、双酯的物质的量比值由3．85提高到10．36。     

有机溶剂法合成聚马来酸酐:聚合残液的分析与循环利用

以过氧化苯二甲酰为自由基引发剂,甲苯为溶剂,研究了聚马来酸酐(PMA)最佳合成条件,即引发剂质量分数10%,反应温度95℃,反应时间6 h。通过对聚合残液的MS分析,聚合残液主要成分为马来酸酐(MA),通过聚合残液的酸值分析,得到MA的利用率为63.5%。针对MA利用率较低,将聚合残液循环利用。循环结果表明,经5次循环使用,MA的累计利用率可达90.3%,并随着循环次数增多,MA的累计利用率逐步增大。所合成聚马来酸酐经FTIR1、HNMR分析,结构正确;凝胶渗透色谱(GPC)分析,每次循环产品PMA的平均相对分子质量变化不大,平均相对分子质量Mn保持在930~940,相对分子质量分布系数为1.12。     

Ionic Substitutions in Biphasic Hydroxyapatite and β-Tricalcium Phosphate Mixtures: Structural Analysis by Rietveld Refinement

The structural information on the influence of ionic additions in biphasic (hydroxyapatite (HAP) and β-tricalciumphosphate (β-TCP)) mixtures ranging from single ionic substitutions to combined ionic substitutions of most of the essential ions embedded in biological apatite was analyzed through the Rietveld refinement technique. The results have proved that the determined quantitative phase composition of HAP and β-TCP in biphasic mixtures was dependent on the initial calcium (Ca) deficiency of the precursor powders precipitated from the different molar concentrations used in the synthesis. The substitution of cations (Na⁺, Mg²⁺, and K⁺) improved the stabilization of the β-TCP structure whereas anions (F⁻ and Cl⁻) were found incorporated at the OH⁻ site of the HAP phase. Rietveld analysis of X-ray powder diffraction data from the present study proved to be a powerful technique to describe the position and occupancy of certain ions like Mg²⁺ and Cl⁻ in the biphasic mixtures. However, it has also shown limitations in tracking back other ions like Na⁺, K⁺, and F⁻, which require the use of other complementary characterization methods.     

Thermal Decomposition of Alkoxides in an Inert Organic Solvent: Novel Method for the Synthesis of Homogeneous Mullite Precursor

Thermal decomposition of a mixture of aluminum iso-propoxide and tetraethoxysilane (Al/Si = 3) in toluene at 300°C was examined. The reaction completely proceeded and yielded an amorphous product. The DTA profile of the product showed a sharp peak at ∼1000°C which was associated with crystallization of mullite and a small amount of the spinel phase. The mullite prepared by calcination of the product at 1300°C was composed of micro-crystals having an average diameter of 30 nm and had a large surface area of 41 m²g.     

Novel Preparation Method of Hydroxyapatite Fibers

A novel method for preparing calcium hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂: HAp) fibers has been developed. HAp fibers can be prepared successfully by heating a compact consisting of calcium metaphosphate (ß-Ca(PO₃)₂) fibers with Ca(OH)₂ particles in air at 1000°C and subsequently treating the resultant compact with dilute aqueous HCl solution. The ß-Ca(PO₃)₂ fibers and the Ca(OH)₂ in the compact were converted into fibrous HAp and CaO phases by the heating, and the CaO phase was removed by acid-leaching. HAp fibers obtained in the present work were 40-150 µm in length and 2-10 µm in diameter. The fibers had almost the same dimensions as those of the ß-Ca(PO₃)₂ fibers.     

溶胶–凝胶法制备纳米羟基磷灰石粉体

以四水合硝酸钙和五氧化二磷为原料，无水乙醇为溶剂，采用溶胶一凝胶法制备了含co}的羟基磷灰石（hydroxy印atite，HAP）粉体。采用热重-差热分析、X射线衍射、透射电子显微镜、Fourier变换红外光谱等研究了反应体系pH值、反应温度及前驱体热处理温度等因素对产物结构与性能的影响规律，结果表明：采用溶胶-凝胶工艺，调控反应体系的pH、反应温度及前驱体的热处理温度是获得纯度高、分散性较好的纳米HAP粉体的关键。pH值为8．0、反应温度为30℃，经600℃热处理可获得到粒径为40~50nm的HAP纳米粉体。     

Synthesis of a Hydroxyapatite/Collagen/Chondroitin Sulfate Nanocomposite by a Novel Precipitation Method

A hydroxyapatite/collagen/chondroitin sulfate nanocomposite that partly mimicked the composition of cartilage was synthesized through a novel precipitation method, using a calcium hydroxide suspension and phosphoric acid solutions that contained several mixing ratios of type II collagen (Col) and chondroitin sulfate (ChS). The precipitates were shaped and consolidated via filter pressing and subsequent cold isostatic pressing, respectively. A preferential alignment of the crystallographic c -axis of the hydroxyapatite nanocrystals along the longitudinal direction of the Col and ChS mixture was observed. The fracture strength and Vickers hardness of the nanocomposites were in the ranges of 35–50 and 119–219 MPa, respectively. This nanocomposite may be applicable for use as a bone substitute, because of its potential capability of bone remodeling through endochondral ossification.     

Facile Synthesis of Element‐Substituted Hydroxyapatite Whiskers Using α‐Tricalcium Phosphate as Precursors

In the absence of any surfactants, organic solvents or structure‐directing reagents, the cation‐ and anion‐substituted HAp whiskers, and cation‐/anion‐co‐substituted HAp whiskers with controllable substitution amounts were successfully synthesized via hydrothermal treatment of the same precursor of α‐TCP in an aqueous solution containing the objective substituted elements. Through regulating the initial ion concentrations of the aqueous solutions, the element substitution level could be well facilely tailored. The cytocompatibility of the products was confirmed by Cell Counting Kit‐8 (CCK‐8) assay using the osteoblast cell line MC3T3‐E1. This study provided a facile strategy for the synthesis of element‐substituted HAp materials.     

药物合成过程中有机溶剂残留量的检测

在药物合成中，因使用了不同种类的溶剂，所以溶剂的残留量是不可避免的，国家对禁止使用，限制使用的溶剂有明确的规定。本文确定了药物合成过程中经常使用的有机溶剂（乙醇，乙腈，二氯甲烷）残留量的检测方法。     

几种电解质在有机溶剂水混合溶剂中的溶解度

实验测定了KNO3 ,KCl,NaCl,K2 SO4 在甲醇、乙醇、丙酮、二乙胺分别与水形成的混合溶剂中的溶解度。用热力学模型推算了这些体系中电解质的溶解度 ,并用实验数据关联出模型中的参数 ,推算结果与实验相符。     

超声化学法合成羟基磷灰石-明胶复合材料

以Ca（NO3）2,（NH4）2HPO4,明胶和戊二醛为原料,用超声化学法合成了尺寸约为30nm×100nm,平均长径比在2-3,分散性良好的羟基磷灰石-明胶复合材料。对比研究了超声化学法与传统化学沉淀法对复合材料结晶性能和力学性能的影响。结果表明,与传统化学沉淀法相比,超声化学法可以在较短时间内显著提高羟基磷灰石的结晶度、改善结晶状态,使复合材料的抗拉强度和抗压强度分别达到52．4MPa和56．8MPa。     

Solubilities of Isophthalic Acid in Acetic Acid + Water Solvent Mixtures

The solubilities of isophthalic acid (1) in binary acetic acid (2)+water (3) solvent mixtures were determined in a pressurized vessel. The temperature range was from 373.2 to 473.2K and the range of the mole fraction of acetic acid in the solvent mixtures was from x₂ 0 to 1. A new method to measure the solubility was developed, which solved the problem of sampling at high temperature. The experimental results indicated that within the temperature range studied, the solubilities of isophthalic acid in all mixtures showed an increasing trend with increasing temperature. The experimental solubilities were correlated by the Buchowski equation, and the calculate results showed good agreement with the experimental solubilities. Furthermore, the mixed solvent systems were found to exhibit a maximum solubility effect on the solubility, which may be attributed to the intermolecular association between the solute and the solvent mixture. The maximum solubility effect was well modeled by the modified Wilson equation.     

金属铟促进下有机相中合成高烯丙基醇

主要研究了以四氢呋喃作为反应溶剂,三甲基氯硅烷作为活化剂,金属铟促进下醛与烯丙基溴生成高烯丙基醇的反应。讨论了三甲基氯硅烷的用量及了不同反应底物对反应的影响,得出反应的最佳条件是三甲基氯硅烷与醛的比2/1,并且发现只有吸电子基及卤素取代的芳香醛反应速度较快,收率好,其它醛的反应较复杂。