耦合闪蒸的连续超临界甲醇法制备生物柴油

在耦合闪蒸装置的管式反应器中,以菜籽酸化油为原料,采用超临界甲醇法连续制备生物柴油,同时绝热闪蒸回收甲醇,考察了醇油摩尔比、反应温度、反应压力、反应时间以及闪蒸压力对生物柴油收率、甲醇回收率及气相中甲醇含量的影响。结果显示,在醇油摩尔比35∶1,反应温度300℃,反应压力13 MPa,反应时间600 s的最优条件下,生物柴油收率可达83.1%(以菜籽酸化油质量计);在最优条件及闪蒸压力为常压条件下,闪蒸甲醇回收率可达90.5%,气相中甲醇含量达97.7%;对闪蒸回收的甲醇循环使用5次后,甲醇回收率为86.8%,回收甲醇中甲醇的质量分数为93.7%,该组成的回收甲醇对生物柴油收率无明显影响。     

超声制备甲醇乳化柴油影响因素的响应面法优化

采用超声制备甲醇乳化柴油,通过正交实验筛选乳化剂配比;采用高速分散器预乳化和超声波装置深度乳化,考察了超声时间和功率、甲醇和乳化剂含量等因素对甲醇乳化柴油稳定性的影响;在单因素实验基础上,基于Box-Behnken实验设计,利用Design-Expert数据分析软件的响应面分析法优化了工艺条件,并建立了以甲醇乳化柴油稳定时间为响应值的数学模型.结果表明,适宜的乳化剂质量比为油酸:Span-80:OP-10:Tween-80:羧甲基纤维素钠=14:5:2:1:5,HLB值为4.48.各因素对甲醇乳化柴油稳定性的影响程度为乳化剂含量?超声功率?甲醇含量?超声时间,交互作用程度为超声时间和功率?超声功率和乳化剂含量?甲醇含量和乳化剂含量?超声时间和乳化剂含量?超声时间和甲醇含量;最优工艺条件为超声时间20 min、超声功率220 W、甲醇含量10%、乳化剂含量5%.在最优条件下进行实验,稳定时间实验值与预测值的相对偏差为2.69%,表明响应面拟合方程可用于超声制备甲醇乳化柴油稳定性的预测和最优工艺条件的确定.     

甲醇合成生产的影响因素及操作控制

初步探讨了合成工艺条件、入塔气中的甲醇含量、原料气中毒物含量等对甲醇合成的影响,简单介绍了各个影响因素在低压甲醇合成生产中的操作控制。     

甲醇合成影响因素与粗甲醇中乙醇含量超标研究

操作条件、入塔气组成以及催化剂性能是影响甲醇合成反应的主要因素。文章对甲醇合成反应的影响因素进行分析,找出甲醇装置开车初期粗甲醇中乙醇含量超标的具体原因,并在此基础上进行优化操作,粗甲醇中乙醇含量达到或优于设计指标。     

MES中甲醇含量的测定方法

建立了一种品红亚硫酸比色法测定MES中甲醇含量的方法。甲醇在酸性条件下被高锰酸钾氧化成甲醛,甲醛与品红亚硫酸作用生成蓝紫色化合物,根据颜色深浅与标准系列比较达到测定MES中甲醇含量的目的。经多次实验证明甲醇含量在0～1.0mg/15mL范围内吸光度呈现良好的线性关系。线性回归方程y=0.2037x-0.02833,相关系数γ=0.9986。此法快速、准确、灵敏度高。实测样品中甲醇的回收率为91.3%～103.7%、相对标准偏差(n=6)为1.33%～3.33%。     

响应面法优化产低温脂肪酶工程菌Cl02的发酵条件

目的采用响应面法优化产低温脂肪酶工程菌Cl02的发酵条件。方法通过单因素试验考察培养基中酵母氮源含量、pH值、甘油含量和甲醇含量对酶活的影响,确定产酶的主要影响条件,在此基础上,根据Box-Benheken中心组合试验设计原理,采用三因素三水平的响应面分析法,综合考察各因子对低温脂肪酶酶活的影响,建立低温脂肪酶酶活的二次回归模型。结果培养基中酵母氮源含量、pH值和甲醇含量对酶活的影响显著。最适产低温脂肪酶条件为:酵母氮源含量7.3 g/L、pH 6.0、甲醇含量9.1 g/L,在此条件下,低温脂肪酶酶活可达42.25 IU/ml,比优化前(28.0 IU/ml)提高了50.9%。结论利用响应面法优化的发酵条件可显著提高工程菌的产酶能力,为规模化生产低温脂肪酶奠定了基础。     

甲醇溶剂法分离蚕蛹油多不饱和脂肪酸

采用甲醇溶剂法分离蚕蛹油多不饱和脂肪酸。通过单因素实验探讨了温度、甲醇浓度、甲醇脂肪比、时间对多不饱和脂肪酸分离效果的影响,然后通过正交实验确定了多不饱和脂肪酸分离的较佳条件。结果表明,适宜的分离条件为：温度-10℃,甲醇浓度90%（w）,甲醇脂肪比2.5,结晶时间30min,在上述条件下多不饱和脂肪酸得率为62.3%,含量由71.0%提高到95.8%。     

浆态床甲醇脱水反应特性研究

考察了温度、压力以及液体空速等操作条件对反应过程的影响，同时探讨了惰性溶剂中水含量对甲醇转化率的影响，为浆态床一步法二甲醚合成工艺研究提供基础实验数据，实验结果表明，在所研究的温度范围内，甲醇转化率随温度升高而增加，在低压条件下甲醇转化率随空速的增加单调递减，而在高压下，由于水在浆液中不断积累，不利于甲醇转化，减小体系中水的含量能明显提高甲醇的转化率。     

用乙醇作内标物气相色谱法测定甲醇汽油中的甲醇含量

为了提高醇类燃料中甲醇含量测量的准确度和精密度,建立了以乙醇作为内标物用气相色谱测定甲醇汽油中甲醇含量的分析方法。通过实验,考察了分流比、阀切换时间等因素对实验结果的影响,确定了最佳实验条件;同时对该方法的准确度和精密度进行了验证。结果表明:在柱温60℃、汽化室温度230℃、检测器温度250℃,载气流速30mL/min的条件下,色谱分离效果好。对同一样品分析,标准差为0.1062,变异系数为1.11%;对自配的5个不同浓度的样品进行分析,相对误差均小于5%。相对于其他方法而言,用气相色谱法测量提高了分析的精密度和准确度,适用于低比例甲醇汽油中甲醇含量的测定。相对外标法而言,内标法准确度高,且重复性好。     

剩余碳五中甲醇含量超标原因分析及对策

某炼油厂催化轻汽油醚化装置在开工初期甲醇萃取塔顶剩余碳五中甲醇含量高达1.2%以上,造成全厂调合汽油中甲醇超标。通过优化工艺操作条件,分析校对甲醇萃取塔填料层高度、直径和分布器等。发现甲醇萃取塔未设置液体再分布器,对此提出了将每段填料的底部、中部的支撑格栅更换为分散/支承板的改造措施。改造后甲醇萃取塔操作正常,剩余碳五中甲醇含量降至100~200mg/kg之间,达到了预期的效果。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。