烟用二醋酸纤维纺丝丙酮/空气混合气(VLA)高浓度控制及其应用

丙酮/空气混合气(VLA)中丙酮浓度是烟用二醋酸纤维丝束生产的一个重要工艺参数。文章以理论计算为指导,从干燥机VLA和纺丝机VLA丙酮浓度两方面,介绍了提高丙酮浓度的可行性,和高丙酮浓度运行下的控制方法。运行结果显示,在保证安全的前提下,提高纺丝VLA浓度,丙酮回收所需的蒸汽消耗显著降低,生产运营成本降低。     

Diisopropyl ether one-step generation from acetone-rich feedstocks

A one-step integrated process for the generation of the high-octane fuel ether, diisopropyl ether (DIPE), from acetone-rich feedstocks has been demonstrated. Three continuous, downflow, reactor configurations have been considered, including a two-bed catalyst design separated by inerts, gradient multicatalyst combinations, and an integrated two-zone layout with differing catalyst compositions. The bifunctional catalysts have both hydrogenation and etherification/dehydration capabilities and may comprise groups IB, VIB, and VIII metals incorporated into acidic, large and medium-pore zeolites, groups III or IV metal oxides, as well as heteropoly acid structures. DIPE syntheses are typically conducted at 100–165°C, under hydrogen pressure. The gradient reactor design, with careful choice of hydrogenation and etherification catalysts, allows DIPE to be generated in high selectivity and productivity. This revised version was published online in July 2006 with corrections to the Cover Date.     

Acetone transformation into methyl isobutyl ketone over Pt/HMFI catalysts. IV. Effect of density and strength of the acidic sites

Acetone transformation into methyl isobutyl ketone (MIBK) was studied using a fixed-bed dynamic reactor at 160°C, 1 atm pressure and acetone/H₂ molar ratio=3. The reaction was carried out over Pt/HMFI bifunctional catalysts, with 0.30 wt% of platinum which was supported over three aluminosilicates (Si/Al ratio=40, 95 and 160) and a borosilicate (Si/B ratio=44) with similar dispersion. The results show that catalytic properties depend greatly on density and strength of the acidic sites of the catalysts. Moreover, the limiting step of the MIBK synthesis reaction (aldolization of two acetone molecules) is carried out over the acidic sites of the aluminosilicates, but not over those of the borosilicate, which considerably affects reaction selectivity. This revised version was published online in July 2006 with corrections to the Cover Date.     

PC微流控芯片黏接筋与溶剂的协同辅助键合

为了在微流控芯片上形成封闭的微通道等功能单元,克服热压键合中微流控结构的塌陷和热压所致芯片微翘曲对后续键合的影响,提出了一种适用于硬质聚合物微流控芯片的黏接筋与溶剂协同辅助的键合方法。以聚碳酸酯(PC)微流控芯片为研究对象,通过热压法在PC微流控芯片上的微通道两侧制作凸起的黏接筋,通过化学溶剂丙酮微溶PC圆片的表面,然后将PC圆片与带有黏接筋的PC微流控芯片贴合、加压、加热,从而实现微流控芯片的键合。分析了键合机理,并对键合工艺参数进行了优化。实验结果表明:键合质量受丙酮溶剂溶解PC圆片的时间和键合温度的影响,能够保证键合质量的最佳键合温度为80~90°,溶解时间为35~45s,芯片的键合总耗时为3min。与已有键合工艺相比,所提出的黏接筋与溶剂辅助键合工艺有效提高了键合效率。该键合方法不仅适用于具有不同宽度尺寸微通道的微流控芯片,还可扩展用于不同材料的硬质聚合物微流控芯片。     

水性聚氨酯粘合剂中丙酮含量的测定

该方法选用401有机载体为固定相,装入柱长2m,内径3mm的玻璃或不锈钢色谱柱中,采用泵抽法装柱,通N2于190℃老化24h;以甲醇为内标,蒸馏水为溶剂,FID为检测器,对水性聚氨酯粘合剂样品中丙酮含量进行气相色谱分离和测定。结果表明:丙酮的标准偏差0.028;变异系数0.41%;回收率99.7%,线性相关系数r=0.9999。该方法测定速度快,结果准确,重现性好。     

降低烟用二醋酸纤维丝束残余丙酮含量的分析及措施

降低烟用二醋酸纤维丝束的残余丙酮含量,对提高丝束产品的质量有重要作用,运用纤维物料干燥原理,分析生产过程中烟用二醋酸纤维丝束残余丙酮与干燥、加湿的关系,同时结合干燥设备提出有效降低烟用二醋酸纤维丝束残余丙酮的方法和措施,具有实际的运用价值。     

乙酰丙酮比色法测定树脂类皮革化学品中游离甲醛的含量

本文论述了限制皮革化学品中游离甲醛含量的意义以及用乙酰丙酮比色法测定皮革化学品中游离甲醛含量的优越性和操作方法。     

超声波辅助从浓缩磷脂中提取高纯粉状磷脂的研究

以大豆浓缩磷脂(CSP)为原料,丙酮为溶剂,提取高纯度粉状磷脂。针对传统有机溶剂法萃取制备粉状磷脂工艺过程中,物料粘度大,容易团聚成块,脱油操作极其困难,萃取效率低等问题,提出了超声波辅助均质萃取新技术。并对较佳的工艺操作条件的选择进行了研究。通过正交实验得出优化的条件为:萃取次数5次,萃取温度0℃,浓缩磷脂与丙酮之比为1/12g/mL,超声波辅助剪切转速5000r/min。产品丙酮不溶物可达98%以上。     

Modification of Crude Canola Lecithin for Food Use

Crude canola lecithin was fractionated by removal of neutral lipids with acetone followed by ethanol extraction with or without supercritical carbon dioxide (SC-CO₂). Two extraction steus of 60 min each at 35°C with 500 mL acetone were optimum for maximum yield of acetone solubles and maximum phospholipid (PL) concentration (66.7%) in the acetone insoluble (AI) fraction. AI were separated into 26.5% ethanol soluble and 68.7% ethanol insoluble fractions. PL concentration in the extract increased with increasing amounts of ethanol used. Yields were low for SC-CO₂/ethanol extraction, of which extracts from 55.2 MPa/ 70°C contained 32% PL (83% phosphatidyl choline).