Hydrolytic degradation of poly[(R)-3-hydroxybutyric acid] in the melt

Poly[(R)-3-hydroxybutyric acid] [R-P(3HB)] was hydrolyzed in high-temperature and high-pressure water at the temperature range of 180-300 °C and for a period of 360 min. The formation, racemization, and decomposition of 3-hydroxybutyric acids (3HBs) and molecular weight change of R-P(3HB) were investigated. The highest yield of (R)-3-hydroxybutyric acid (R-3HB), ca. 80%, was obtained at 200 °C in the hydrolytic degradation periods of 240-360 min. Too-high hydrolytic degradation temperature such as 300 °C induced the decomposition and racemization of formed 3HBs, resulting in decreased yield of R-3HB. The hydrolytic degradation of R-P(3HB) proceeds homogeneously and randomly via a bulk erosion mechanism. The molecular weight of R-P(3HB) decreased exponentially without formation of low-molecular-weight specific peaks originating from crystalline residues. The hydrolytic degradation rates in the melt estimated from M_n changes were lower for R-P(3HB) than for poly(l-lactide) (PLLA) in the temperature range of 180-220 °C. The activation energy for the hydrolytic degradation (ΔE_h) of R-P(3HB) in the melt (180-250 °C) was 30.0 kcal mol⁻¹, which is higher than 12.2 kcal mol⁻¹ for PLLA in the melt in the temperature range (180-250 °C). This study reveals that hydrolytic degradation of PHB in the melt is an effective and simple method to obtain (R)-3HB and to prepare R-P(3HB) having different molecular weights without containing the specific low-molecular-weight chains, because of the removal of the effect caused by crystalline residues.     

Magnetic behavior within a new Ni(mnt)2-based molecular solid containing 1-(2′-fluorobenzyl)isoquinolinium

A novel molecular solid, [OFBzIQl][Ni(mnt)₂] (1), where [OFBzIQl]⁺ = 1-(2′-fluorobenzyl)isoquinolinium and mnt²⁻ = maleonitriledithiolate, forms 1D column of alternating between cations and anions via ππ stacking interaction between Ni(mnt)₂ plane and isoquinoline ring, and the Ni(mnt)₂ anions between the adjacent columns exist short CN interaction. The extensive hydrogen bonds between anions and cations in the crystal generate a 2D network structure. Magnetic susceptibility measurement for 1 in the temperature range 2.0–300 K shows that 1 exhibits a magnetic constant transition from ferromagnetic to antiferromagnetic around 35 K as the temperature is lowered.     

离子对液相色谱法分析2-呋喃甲酸的研究

介绍了用离子对液相色谱外标法对2-呋喃甲酸分析的方法,方法的标准偏差为0.4774,变异系数为0.53%,回收率为98.93%。     

EH-2中温耐硫水解催化剂与单醇精脱硫工艺

介绍了EH-2中温耐硫水解催化刑的实验室试验项目和实验数据,分析了EH-2的工厂侧流试验结果,论述了由EH-2催化刑与常温精脱硫新工艺组成的精脱硫组合技术在单醇生产中的工业应用效果。结果表明,甲醇催化刑寿命超过3年,每立方米催化剂的甲醇生产强度达到14000t。     

3-N-丙酰基-1，3，4-噁唑啉类化合物的合成

4-甲氧基苯甲酰肼（1）与芳醛反应得到相应的酰腙（2a～2j），2a～2j分别与丙酸酐脱水环化成了3-N-丙酰基-1，3，4-嗯唑啉类化合物（3a～3j），通过元素分析、IR、1^HNMR和MS对化合物3a～3j的结构进行了表征。     

聚合物冻胶类堵剂在油田堵水中的应用

在油田堵水作业中聚合物类堵剂得到了广泛的应用,美国FOR方案设计中有35％采用聚合物,而其中的60％采用的是冻胶处理;在国内,聚合物冻胶类堵剂在油田八大类堵水体系中也占有较大的比例。文章描述了聚合物冻胶类堵剂在国内外的发展现状,根据聚合物类型的不同对该类冻胶进行分类,并介绍了其作用机理、应用情况、施工工艺以及理论研究情况,其中PI决策技术已经被广泛地用于指导油田调剖作业,最后指出针对深层、高温油藏聚合物冻胶类堵剂仍有广阔的发展前景。     

（E）-2-壬烯酸合成方法的改进

(E)-2-壬烯酸是有机合成的一种重要中间体,我们利用Knoevenagel反应机理,改进了(E)-2-壬烯酸的合成工艺,在不使用脱水剂条件下,使用少量吡啶作催化剂,获得了83%的反应收率。     

夏季面漆起泡的预防

面漆漆膜在夏季潮湿天气下成膜后3—5天，漆膜表面易形成米粒状的漆泡，针对漆泡的现象，寻找其形成的机理，根据起泡的机理采取预防面漆起泡的措施。     

双手性识别HPLC法拆分3-(2-氯乙基)-2-(2-氯乙基氨基)四氢-2H-1,3,2-噁嗪磷-2-氧化物对映体

建立了拆分3-(2-氯乙基)-2-(2-氯乙基氨基)四氢-2H-1,3,2-口恶嗪磷-2-氧化物(异环磷酰胺)对映体的双手性识别HPLC方法。以三苯基氨基甲酸酯-纤维素(CTPC)为手性固定相,以添加N-苄氧羰基-S-苯基-L-半胱胺酸(BPC)为手性添加剂的正己烷、异丙醇为手性流动相,V(正己烷)∶V(异丙醇)=90∶10,c(BPC)=0.4 mmol/L,流动相流速为0.8 mL/m in,检测波长为254 nm,异环磷酰胺对映体的分离选择性系数为1.12,分离度为1.91,质量浓度测定的线性范围为0.5~2.6 mg/mL,相对标准偏差为0.21%~0.59%,最小检测限为0.86μg。     

仿生学在建筑涂料中的应用——荷叶效应乳胶漆

论述了荷叶效应乳胶漆的开发、机理和耐沾污性等。