SIPE合成实验研究

本文研究了在SIPM（间苯二甲酸二甲酯－5－磺酸钠）和EG（乙二醇）合成SIPE（间苯二甲酸双羟乙酯－5－磺酸钠）过程中催化剂,反应温度,酯交换率对反应的影响及其控制。     

新型聚酯聚醚共聚型亲水整理剂的合成及其性能

以间苯二甲酸二甲酯-5-磺酸钠(SIPM)为改性单体,合成一种新型聚酯聚醚共聚型亲水整理剂.研究SIPM添加量,缩聚反应温度、时间,催化剂用量对整理剂水溶性和亲水性能的影响,优化合成工艺条件.用FT-IR、热重分析仪、X射线衍射仪对整理剂结构和性能进行研究,并对其应用性能进行探讨.结果表明:当SIPM摩尔用量为二元酯(...     

阳离子染料可染改性PBT纤维的研究

以间苯二甲酸二甲酯—5—磺酸钠(SIPM)作改性剂采用酯交换路线合成的改性PBT共聚酯(CDPBT)以赋予PBT以阳离子染料可染性,并经纺丝和牵伸得CDPBT纤维。本文主要涉及SIPM的加入对合成反应的影响,对CDPBT树脂及纤维性能的影响,尤其是对染色性能的改进。     

固体超强酸SO42-/ZrO2-凹凸棒催化合成乳酸丁酯

以固体超强酸SO42-/ZrO2-凹凸棒为催化剂,乳酸和丁醇为原料合成乳酸丁酯.考察了反应物摩尔比,催化剂用鼍,反应温度,反应时间,催化剂重复使用等因素对反应的影响.实验结果表明,当n(正丁醇):n(乳酸)=3.0:1,SO42-/ZrO2-凹凸棒用量为乳酸质量的4.0%,反应温度115℃,反应3.0 h时,乳酸的酯化率达96.64%.催化剂回收简单,重复使用5次后,乳酸的酯化率仍为92.04%.     

荧光增白剂CBS的合成新方法

以氯氯苄,三苯基膦和邻磺酸钠苯甲醛为原料,经Witting-Horner反应制得4-氯-二苯乙烯-2'-磺酸钠,然后在含Ni催化剂的作用下制得了荧光增白剂CBS[4,4'-双-2-(磺酸钠苯乙烯基)联苯].该工艺规避了联苯的氯甲基化过程,可减少有毒物质的排放量,为合成联苯类荧光增白剂提供了1种新方法.优化后的反应条件:中间体的合成温度为50℃,n(碱)∶n(三苯基膦)为1.1∶1.0;合成CBS反应温度为80℃,催化剂用量为5%.总收率可达64.9%以上.     

对甲苯磺酸催化制备脂肪酸丁酯工艺研究

以对甲苯磺酸(PTS)为催化剂,大豆油和正丁醇为原料进行酯交换反应制备脂肪酸丁酯。考察醇油摩尔比、催化剂用量、反应温度以及反应时间对大豆油酯交换率的影响。结果表明,最佳合成工艺条件为:n(醇)∶n(油)=7.3∶1,w(PTS)=5%(以大豆油和正丁醇的总质量计),反应温度130℃,反应时间4.5h,在此条件下,酯交换率可达到89.4%。     

没食子酸-1,4-丁二醇单酯的合成及其鞣制性能研究

以对甲苯磺酸为催化剂,用过量1,4-丁二醇与没食子酸(GA)酯化脱水,合成了没食子酸-1,4-丁二醇单酯(BG),通过正交实验考察了反应条件对产率的影响,确定了最佳的合成路线:催化剂用量为没食子酸质量的6%,n(1,4-丁二醇):n(CA)=15:1,反应温度120℃,反应时间5 h,该条件下反应产率可达83.2%,熔点158.3～159.0℃,产物为白色晶体.采用IR、1HNMR对产品的分子结构进行了表征.将BG与铝盐结合用于皮革鞣制,坯革收缩温度可达88.5℃,与酸皮相比收缩温度提高了27.7℃.     

固体超强酸S_2O_8~(2-)/ZrO_2-CeO_2催化制备聚乙二醇菜籽油脂肪酸酯的研究

以固体超强酸S2O82-/ZrO2-CeO2为催化剂,将菜籽油醇解所得脂肪酸甲酯与聚乙二醇400(PEG-400)酯交换制备非离子表面活性剂聚乙二醇菜籽油脂肪酸酯。考察了反应物质量比、催化剂用量、反应时间、反应温度和催化剂重复使用等因素对反应的影响。结果表明,在m(脂肪酸甲酯)∶m(PEG-400)=2.8∶1,催化剂用量为反应物总质量的1.5%,温度为130℃,反应7 h时,PEG-400的酯交换率为91.56%,催化剂重复使用5次后,PEG-400的酯交换率仍比较高。用傅里叶红外光谱仪、表面张力仪等手段对产品的结构和理化性能进行了考察,产品的浊点指数为19.98 mL、表面张力γ(临界胶束浓度)为27.04 mN/m、乳化力622 s、润湿力59 s,具有很好的表面活性。     

1-(3-磺酸基)-丙基-2-吡咯烷酮硫酸氢盐与碳酸钾催化酯交换性能

合成并表征1-(3-磺酸基)-丙基-2-吡咯烷酮硫酸氢盐([C3SO3Hnbp]HSO4)质子酸离子液体，将其应用于大豆油与甲醇酯交换反应，对影响离子液体酯交换反应因素进行考察，并将其催化性能与以碳酸钾为催化剂酯交换反应进行对比分析。实验结果表明，在各自最佳反应条件下，离子液体具有比碳酸钾更好酯交换反应活性，但前者达到...     

棕榈油改性制备皮革加脂剂的研究

以棕榈油为原料,通过酯交换反应、硫酸化改性制备皮革加脂剂.采用正交试验法优化的甲醇酯交换反应条件为:n(甲醇):n(棕榈油)=3:1,在65℃时加入催化剂甲醇钠0.5%(质量分数)反应1 h.此优化条件下引入羟基量适中,酯交换深度较好.对改性棕榈油进行硫酸化,当m(硫酸):m(改性棕榈油)=25%,在25～30℃温度下反应5 h,制得的加脂剂呈棕黄色,流动性较好,水乳液稳定性好.     

Arsenic(III) oxidation by iron(VI) (ferrate) and subsequent removal of arsenic(V) by iron(III) coagulation

We investigated the stoichiometry, kinetics, and mechanism of arsenite [As(III)] oxidation by ferrate [Fe(VI)] and performed arsenic removal tests using Fe(VI) as both an oxidant and a coagulant. As(III) was oxidized to As(V) (arsenate) by Fe(VI), with a stoichiometry of 3:2 [As(III):Fe(VI)]. Kinetic studies showed that the reaction of As(III) with Fe(VI) was first-order with respect to both reactants, and its observed second-order rate constant at 25 degrees C decreased nonlinearly from (3.54 +/- 0.24) x 10(5) to (1.23 +/- 0.01) x 10(3) M(-1) s(-1) with an increase of pH from 8.4 to 12.9. A reaction mechanism by oxygen transfer has been proposed for the oxidation of As(III) by Fe(VI). Arsenic removal tests with river water showed that, with minimum 2.0 mg L(-1) Fe(VI), the arsenic concentration can be lowered from an initial 517 to below 50 microg L(-1), which is the regulation level for As in Bangladesh. From this result, Fe(VI) was demonstrated to be very effective in the removal of arsenic species from water at a relatively low dose level (2.0 mg L(-1)). In addition, the combined use of a small amount of Fe(VI) (below 0.5 mg L(-1)) and Fe(III) as a major coagulant was found to be a practical and effective method for arsenic removal.     

Iron(VI) and iron(V) oxidation of copper(I) cyanide

Copper(Il) cyanide (Cu(CN)4(3-)) in the gold mine industry presentsthe biggest concern in cyanide management because it is much more stable than free cyanide. Cu(CN)4(3-) is highlytoxic to aquatic life; therefore, environmentally friendly techniques are required for the removal of Cu(CN)4(3-) from gold mine effluent. The oxidation of Cu(CN)4(3-) by iron-(VI) (FeVIO4(2-), Fe(VI)) and iron(V) (FeVO4(3-), Fe(V)) was studied using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 5HFeO(4-) + Cu(CN)4(3-) + 8H2O - > 5Fe(OH)3 + Cu2+ + 4CNO- +3/202 + 6OH-. The rate law for the oxidation of Cu(CN)4(3-) by Fe(VI) was found to be first-order with each reactant. The rates decreased with increasing pH and were mostly related to a decrease in concentration of reactive protonated Fe(VI) species, HFeO4-. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate constant for the oxidation of Cu(CN)4(3-) by Fe(V) was determined at pH 12.0 as 1.35 +/- 0.02 x 10(7) M(-1) s(-1), which is approximately 3 orders of magnitude larger than Fe(VI). Results indicate that Fe(VI) is highly efficient for removal of cyanides in gold mill effluent.     

Mind the (yield) gap(s)

This paper explores the origin of the notion of ??yield gap?? and its use as a framing device for agricultural policy in sub-Saharan Africa. The argument is that while the yield gap of policy discourse provides a simple and powerful framing device, it is most often used without the discipline or caveats associated with the best examples of its use in crop production ecology and microeconomics. This argument is developed by examining how yield gap is used in a selection of recent and influential agricultural policy documents. The message for policy makers and others is clear: ??mind the (yield) gap(s)??, for they are seldom what they appear.     

Supercritical fluid extraction (SFE) of 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI) from ground-coffee with high-performance liquid chromatographic-electrospray mass spectrometric quantification (HPLC/ESI-MS).

Two polar analytes, 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI), were extracted with supercritical carbon dioxide (CO2) modified with aqueous methanol. The method was applied to a roasted coffee powder with good recovery rates. Method efficiency was compared with that of solid-phase extraction using SCX Disc cartridges and validated for spiked solid matrix. The analytes were determined using isocratic liquid chromatography-mass spectrometry (LC/MS) on an Atlantis HILIC Silica column (150 x 2.1 mm, 3 microm) with 80% methanol and 20% 0.01 mol l-1 ammonium formate as the mobile phase. The limit of quantification was around 1.5 pg for 4-MeI and 2.0 pg for THI. The linearity of the calibration curves was satisfactory as indicated by correlation coefficients of >0.999. The coefficient of variation for the intra-day and inter-day precisions was <4% (n = 6). Accuracy was in the range 98-101%; recovery rates were > or = 98 and > or = 99% for THI and 4-MeI, respectively. Several samples of Arabica coffee from various locations and commercially available 'off-the-shelf' coffee products (Arabica/Robusta mixtures) were analysed to test the method.     

优质农业生产管理指导手册

优质农业生产管理体系(GAP)概念提出的目的在于确保烟叶生产的持续、健康发展,可以将GAP定义为:在保护、维持或增强土壤、水源、空气、动植物生命和环境的同时,在确保农业生产可持续发展的条件下,推行一系列农业措施,生产出一定产量和质量的优质农作物.     

Reduction of Tc(VII) by Fe(II) sorbed on Al (hydr)oxides

Under oxic conditions, Tc exists as the soluble, weakly sorbing pertechnetate [TcO4-] anion. The reduced form of technetium, Tc(IV), is stable in anoxic environments and is sparingly soluble as TcO2 x nH2O(s). Here we investigate the heterogeneous reduction of Tc(VII) by Fe(II) adsorbed on Al (hydr)oxides [diaspore (alpha-AlOOH) and corundum (alpha-Al2O3)]. Experiments were performed to study the kinetics of Tc(VII) reduction, examine changes in Fe surface speciation during Tc(VII) reduction (M?ssbauer spectroscopy), and identify the nature of Tc(IV)-containing reaction products (X-ray absorption spectroscopy). We found that Tc(VII) was completely reduced by adsorbed Fe(II) within 11 (diaspore suspension) and 4 days (corundum suspension). M?ssbauer measurements revealed thatthe Fe(II) signal became less intense with Tc(VII) reduction and was accompanied by an increase in the intensity of the Fe(III) doublet and magnetically ordered Fe(III) sextet signals. Tc-EXAFS spectroscopy revealed that the final heterogeneous redox product on corundum was similar to Tc(IV) oxyhydroxide, TcO2 x nH2O.     

优质农业生产管理指导手册(二)

4病虫害综合防治 病虫害综合防治(IPM)是烟叶生产的一项系统体系,利用病虫害预测预报系统,提供最好的病虫害综合防治决策,重点是协调应用一切可行的办法.病虫害综合防治并不意味着完全排除使用农药,而是在使用其它办法不能使病虫害的种群数保持在可接受的范围时适当使用农药.施用农药的地方应确保安全,并遵守一切法律法规.     

优质农业生产管理指导手册(三)

7 烘烤（调制）和烤房管理 烟叶的正确烘烤和烤房管理对优化烟叶的产量、质量和产值来说是非常关键的因素。烟叶烘烤是保持烟叶产量、质量的最后一道环节。烟叶质量会因烘烤不当而降低，而正确进行烘烤能确保烟叶质量的稳定。然而，若将劣质的鲜烟叶或烟株放入烤房，则不可能提高最终的烟叶质量。     

Reactivity of Pb(II) at the Mn(III,IV) (oxyhydr)oxide--water interface

In this study, the reactivity of lead (Pb(II)) on naturally occurring Mn(III,IV) (oxyhydr)oxide minerals was evaluated using kinetic, thermodynamic, and spectroscopic investigations. Aqueous Pb(II) was more strongly adsorbed to birnessite (delta-MnO1.7) than to manganite (gamma-MnOOH) under all experimental conditions. The isoteric heat of Pb adsorption (delta HT) or birnessite was 94 kJ mol-1 at a surface loading of 1.1 mmol g-1, and decreased with increasing adsorption density. This indicated that adsorption was an endothermic process and that birnessite possessed heterogeneous sites of reactivity for Pb. X-ray absorption fine structure (XAFS) spectra revealed that Pb was adsorbed as inner-sphere complexes on both birnessite and manganite with no evidence to suggest oxidation as an operative sorption mechanism. Lead appeared to coordinate to vacancy sites in the birnessite layer structure with concurrent release of Mn to solution, which resulted in a greater number of second shell Mn scatterers in Pb-birnessite when compared to Pb-manganite samples. The difference in Pb coordination apparently explained the contrasting desorption behavior between the two Mn minerals. These results have significant implications for Pb partitioning in soil environments containing solid-phase Mn(III,IV) (oxyhydr)oxides.