松柏醇-β-D-葡萄糖苷-[α-^13C]与造纸废水中LCC的聚合反应机理研究

研究了在木素氧化酶催化的体系下,木素前驱物松柏醇-β-D-葡萄糖苷-[α-^13C]与废水中的木素碳水化合物复合体反应的方法及其机理。采用^13C同位素示踪技术,并结合红外谱图分析、核磁共振技术探讨了松柏醇葡萄糖苷与废水中木素碳水化合物复合体的聚合产物的化学结构。同时应用GPC分析手段测定了聚合产物的相对分子质量。研究表明,木素前驱物松柏醇-β-D-葡萄糖苷能与废水中LCC发生脱氢聚合反应,同时GPC测定的结果表明聚合后相对分子质量也明显增大,从11320上升到23810-36886。反应生成聚合产物为木素-碳水化合物复合体大分子而沉淀析出,在废水中水溶性、难降解木素的LCC可被有效地去除,使废水的污染负荷降低。     

脱氢二香草醇的合成及LCC的形成机理(Ⅱ)

在合成缩合型木素模型化合物——脱氢二香草醇的基础上,模拟硫酸盐法蒸煮过程,将合成的木素模型物和典型的半纤维素组成部分——木糖进行蒸煮,然后利用酸析沉淀木素、乙酸乙酯抽提等方法将蒸煮后的产物分级,并利用FT-IR、13C-NMR对分级后的各个部分进行分析,探讨传统硫酸盐法制浆过程中木素-碳水化合物复合体(LCC)的形成机理。研究发现,脱氢二香草醇在硫酸盐法蒸煮过程中非常稳定,部分脱氢二香草醇与木糖形成LCC连接,未降解的脱氢二香草醇和新形成的LCC主要存在于乙酸乙酯抽提物中,酸不溶物和酸可溶物内都不存在新形成的LCC结构。     

松柏醇-β-D-葡萄糖苷一[α-13C]与造纸废水中LCC的聚合反应机理研究

研究了在木素氧化酶催化的体系下,木素前驱物松柏醇-β-D-葡萄糖苷-[α-13C]与废水中的木素碳水化合物复合体反应的方法及其机理.采用13C同位素示踪技术,并结合红外谱图分析、核磁共振技术探讨了松柏醇葡萄糖苷与废水中木素碳水化合物复合体的聚合产物的化学结构.同时应用GPC分析手段测定了聚合产物的相对分子质量.研究表明,木素前驱物松柏醇-β-D-葡萄糖苷能与废水中LCC发生脱氢聚合反应,同时GPC测定的结果表明聚合后相对分子质量也明显增大,从11320上升到23810～36886.反应生成聚合产物为木素-碳水化合物复合体大分子而沉淀析出,在废水中水溶性、难降解木素的LCC可被有效地去除,使废水的污染负荷降低.     

脱氢二香草醇的合成及LCC的形成机理(Ⅰ)

合成了一种缩合型木素模型化合物——脱氢二香草醇,并利用红外光谱、核磁共振谱(1H-NMR)对其进行了分析和确认。在此基础上,模拟硫酸盐法蒸煮过程,将合成的木素模型物和典型的半纤维素组成部分(木聚糖)进行蒸煮,然后利用酸析沉淀木素、乙酸乙酯抽提的方法将蒸煮后的产物分级,并利用FT-IR、13C-NMR对分级后的各个部分进行分析,探讨传统硫酸盐法制浆过程中木素-碳水化合物复合体(LCC)的形成机理。研究发现脱氢二香草醇在硫酸盐法蒸煮过程中非常稳定,残留的脱氢二香草醇以及新形成的LCC主要存在于酸不溶物、乙酸乙酯抽提物中,大部分未降解的木聚糖存在于酸不溶物中,碱不溶物和酸可溶物内都不存在新形成的LCC结构。     

红麻硫酸盐法蒸煮中溶出木素的分子量分布及变化

采用凝胶色谱法（GPC）对红麻皮和秆芯硫酸盐法蒸煮过程中溶出木素的分子量及其分布的变化进行了研究。结果表明，随着蒸煮的进行，红麻皮和秆芯溶出木素的平均分子量逐渐增大，多分散性和特性粘数也相应增大。此外，在同一蒸煮条件下，红麻秆芯溶出木素的平均分子量高于红麻皮，这也说明了红麻秆芯比红麻皮更难脱木素。研究还发现，红麻原料木素以及溶出木素的分子量分布曲线都呈单峰现象。     

蒸煮液的物理化学特征及在制浆过程中的行为 Ⅱ.木素对蒸煮液的表面张力的影响

通过加入木素自制黑液及取自一个连续等温蒸煮过程的黑液的数据比较,研究了木素对蒸煮液的表面张力的影响。结果显示,木素起着表面活性剂的作用使蒸煮液的表面张力降低。但木素对实际取得的黑液的表面张力的影响要大于人工自制的,其主要原因是前者还含有木材的其它成分,如半纤维素及脂肪酸。黑液表面张力的主要成分是Lifshitz-van der Waals引力 γLLW,其次是Lewis酸碱反应力γLAB。     

核磁共振法在研究木素和碳水化合物结构方面的应用

本文评述了核磁共振法（ＮＭＲ）在木素和碳水化合物结构方面的 应用情况，介绍了以及它们的应用原理和方法．     

稳定同位素标记莨菪亭-2-~(13)C的合成

以2,4,5-三甲氧基苯甲醛和乙酰氯-2-13C为原料,经3步反应合成目标化合物。以原料乙酰氯-2-13C计算,目标化合物总收率为26%,产品经LC-MS、1HNMR、13CNMR、IR检测,化学纯度99%,13C同位素丰度为98.5 atom%。     

硫酸盐竹浆ECF漂白过程中糖类组分变化的研究

应用高效液相色谱法研究了硫酸盐竹浆 ECF 漂白过程中二氧化氯漂白段糖类组分的变化情况。结果表明,葡聚糖、木聚糖和阿拉伯聚糖在二氧化氯漂白过程中有不同的降解率,葡聚糖降解率只有 0.133%,而木聚糖的降解率为 0.907%,阿拉伯聚糖的降解率达 79.77%,明显高于葡聚糖的降解率。     

硫酸盐法提取竹子木素的工艺研究

采用传统的硫酸盐法制浆工艺,对竹子进行木素提取和造纸实验.优化的蒸煮工艺条件为:温度170℃,升温90 min,保温30 min;用碱量17.5%(以NaOH计),硫化度20%,粗浆得率47.65%,废液木素浓度49.43%,木素提取率78.10%,并用电镜、能谱对提取液和纤维进行分析,Na、S含量高,对碱的回收是减少污染的重要问题,提出采用不含Na和S元素的制浆法可减轻对环境的污染,使后处理简化.     

Liquid holdup measurements in turbulent bed contactors by a tracer technique

An experimental technique to eliminate the effects of sensor dynamics when a tracer is used to measure the hydrodynamics of a turbulent bed contactor is described. The resulting liquid holdup data are compared both with predictions from the pressure drop measurements and with the available correlations in the literature. The results show that the pressure drop method and Handl's (1976) equation under-predict liquid holdup, while Rama et al.'s (1983) and Kito et al.'s (1978) equations over-predict the results.     

Comparative study on iodide and bromide isotopic exchange reactions by application of radioactive tracer technique

In the present investigation, a short lived radioactive tracer isotopes ¹³¹I and ⁸²Br were used to study the kinetics of isotopic exchange reactions. For bromide isotopic exchange reaction, the calculated values of specific reaction rate (min⁻¹), and amount of bromide ions exchanged (mmol) were obtained higher than that for iodide isotopic exchange reaction under identical experimental conditions. For both the exchange reactions it was observed that when the concentration of ionic solution was increased twice, the␣percentage of ions exchanged increases sharply at nearly same specific reaction rate, indicating that concentration greatly influences the exchange reactions.     

荧光法测定油田采出水中示踪剂的含量

对示踪剂荧光素性质进行考察,通过对待测水样用KOH调节pH至8,利用荧光法测定油田采出水中示踪剂的含量.该方法简便、快速且灵敏度高,测定值的相对标准偏差在0.167%以内,加标回收率为96.73%～104.00%.     

1H N.m.r. relaxation and molecular motion of polyethylene in solution as studied by the isotopic dilution technique

The molecular motion of polyethylene has been studied in decalin-d₁₈ solution by ¹H n.m.r. relaxation with the isotopic dilution technique which can separate the proton spin-lattice relaxation times into the intra- and intermolecular contributions, intra T₁ and inter T₁. The temperature dependences of intra and inter T₁s show that the intra- and intermolecular motions are in the extreme narrow region. These results, also, were compared with the results of molten polyethylene reported in our previous work.     

人工神经网络研究氨配合法制活性氧化锌

采用工业氧化锌生产中回收的烟道灰为原料，加入过氧化氢进行氧化，提高氧化锌浸取率，并对氨配合法制备活性氧化锌工艺过程中影响浸取率的因素进行研究，用BP(误差反向传播)神经网络对结果进行优化，建立了浸取率的神经网络模型，得到了浸取工艺的最佳工艺条件。结果表明，在此工艺条件下，浸取率可达88.1％。     

Effects of controlled-release coated urea (CRCU) on soil microbial biomass N in paddy fields examined by the 15N tracer technique

Experiments were conducted in paddy fields at Shiga and Chiba Prefectures to study the effects of controlled-release coated urea (N-LP100) on soil microbial biomass and N uptake of rice plants by the ¹⁵N-tracer technique, during one cropping season. Three field fertilizer treatments (Zero N: 0 kgN ha^–1, ¹⁵N-LP100: 64 kg N ha^–1 and ¹⁵NH₄Cl: 100 kg N ha^–1) were set-up in the Shiga field experiment. After transplanting in the paddy fields at Shiga and Kashiwa (Chiba), a number of rice hills with standard growth were selected randomly and enclosed by polyacryl-plastic frames designated as microplots. ¹⁵N-LP100 (64 kg N ha^–1) was applied in the Shiga and Kashiwa microplot experiments and the Shiga field experiment as deep-side placement (5 cm away from rice hill and 5 cm soil depth). Total N uptake of rice plants was analyzed in the course of plant growth. In addition, soils from the field fertilizer treatment plots and microplots (divided into 11 blocks) were taken and analyzed for microbial biomass N (B_N) and biomass ¹⁵N (B_15N). The results indicated that; (1) Plant N uptake from basal-applied fertilizers at the end of the study in the Shiga field experiment was 71.9 and 26.0% for ¹⁵N-LP100 and ¹⁵NH₄Cl, respectively. In the Kashiwa microplot experiment, plant N uptake from applied ¹⁵N-LP100 was 51.2% at 67 days after transplanting (DAT) (2) Throughout the cropping season, B_N was the highest, intermediate and the lowest for ¹⁵NH₄Cl, ¹⁵N-LP100 and Zero N field experimental plots in the Shiga experiment, respectively. (3) In the micro-plot experiments, B_N and B_15N were generally higher in the soil block with deep-side application of ¹⁵N-LP100 compared with the other soil blocks. The deep-side placement of ¹⁵N-LP100 ensured a high efficiency of utilization of its N by rice plants. The method of ¹⁵N-LP100-placement also affected the spatial heterogeneity of microbial biomass N in the microplots.     

Simultaneous measurement of gas hold-up and mass transfer coefficient by tracer dynamic technique in “Emulsair” reactor with an emulsion-venturi distributor

Hydrodynamics and gas-liquid mass transfer have been investigated in an “Emulsair” reactor with cocurrent downflow of gas and liquid. This consists of a cylindrical tank with conical bottom topped by an emulsion-venturi as the gas-liquid distributor in which the gas is self-aspired by action of the kinetic energy of the liquid recirculation. An original tracer dynamic technique using the CO₂-N₂/water system that enables the simultaneous measurement of overall gas hold-up and overall volumetric mass transfer coefficient has been developed and validated using conventional techniques, such as volume expansion for gas hold-up and dynamic oxygenation for mass transfer. It has been shown that gas hold-up and K_La_L can be deduced from the moments of experimental response curves using a CO₂ pulse in the gas feed. Experimental results have proved that hydrodynamics and mass transfer in the Emulsair reactor are strongly influenced by the flow regime in the divergent. Two different regimes have been observed depending on the liquid recirculation flow rate: annular and homogeneous bubbling flows. In both regimes, self-aspired gas flow rate, gas hold-up and K_La_L have been reported to increase with the liquid flow rate. The operation effectiveness, estimated from the gas-to-liquid flow rate ratio, has been shown to pass through a maximum around 0.59 as a function of liquid recirculation. A comparison with the literature proved that this maximum is higher than those observed for other kinds of gas-liquid reactors equipped with a venturi. Correlations for mass transfer estimation have been derived and are in agreement with the literature.     

Utilisation by upland rice of plant residue- and fertiliser-phosphorus in two tropical acid soils

A dual isotopic technique was used to assess the effects of soil type, and residues of Gliricidia sepium, without and with added fertiliser-P on the utilisation of P. Upland rice (Oryza sativa) was grown for 70 days in two tropical acid soils of different P sorbing capacity and P status. Uniformly ³²P-labelled soils were treated with inorganic fertiliser-P tagged with ³³P, Gliricidia sepium residue applied at planting and 3 weeks earlier, and in a combination of fertiliser-P and Gliricidia applied at and 3 weeks before planting. There were significant responses of shoot and root weights, and total P uptake to Gliricidia- and/or fertiliser-P addition in the Ultisol (low P status) but not the Oxisol (high P status), suggesting that P in the latter soil was not yield limiting, despite the high standard P requirement. Similarly, incorporation of Gliricidia three weeks before planting further increased shoot weight only in the Ultisol. There were generally higher proportions, quantities and percent utilisations of the Gliricidia-P and fertiliser-P in the Ultisol than in the Oxisol. Gliricidia significantly increased the utilisation of fertiliser-P only in the Ultisol. However, early application of Gliricidia increased Gliricidia-P but not fertiliser-P utilisation in the Ultisol. Added fertiliser-P did not influence Gliricidia-P utilisation.