生物质合成气调变方式对其合成甲醇的影响

对生物质气、工业合成气、重整后生物质气及配氢后生物质气4种合成气进行了合成甲醇的研究. 发现甲醇产率顺序为工业合成气>重整生物质气>配氢生物质气>生物质气,生物质气合成甲醇产率较低主要是因为其为富CO2体系. 实验同时发现(H2-CO2)/(CO+CO2)比值在1.5~2之间时,(H2-CO2)/(CO+CO2)比值对液相产物中甲醇选择性没有明显影响. 液相产物中甲醇选择性随CO2含量上升而下降.     

非催化加压甲烷部分氧化制合成气

考察了非催化条件下，温度、压力和进气配比对甲烷部分氧化制合成气的影响，结果表明：甲烷的转化率随温度的升高，压力的增加，进气中氧的增加而增加；产物中合成气含量随温度的升高而增加，最高达81％以上；随着温度的升高，产物中H2／CO存在极值，在本实验的研究范围内，最大可达1．8；进气中氧增多，产物中H2／CO减小；温度升高，或压力增大，CO2的选择性也随之提高．对CO选择性的正交分析表明，进气配比对CO选择性影响最大，压力次之，温度的影响最小．     

碳负性镁基水泥的制备及性能研究

通过浓缩海水吸收CO2制备了一种以碳酸镁为主要矿物组成的新型碳负性镁基水泥,着重研究Mg:CO2摩尔比、固碳反应温度及活化温度对碳负性镁基水泥产物及性能的影响.结果表明:浓缩海水中的Ca和Mg离子可通过调整pH值实现完全分离;固碳反应温度为45℃时,Mg:CO2摩尔比为1.5和1.8时,形成的主要产物为介稳镁基物质,MgCO3·3H2 O;当Mg:CO2摩尔比为2.0时,固碳反应温度低于45℃时,反应产物主要为介稳镁基物质,MgCO3·3H2 O;当活化温度控制在300℃以内时,碳负性镁基水泥的活化反应主要是由于结晶水的失去.该新型碳负性镁基水泥具有显著的碳吸附和低碳排放特点.     

HZSM-5催化甲醇制丙烯工艺条件的考察

以工业应用的HZSM-5为催化剂,在连续固定床反应器中考察了反应温度和甲醇分压对甲醇制丙烯反应产物的影响,发现当温度大于450℃时,随着温度的升高,甲醇的转化率都能达到99%以上,乙烯和丙烯的总选择性增加,低碳烷烃选择性增加,高碳产物选择性下降;随着甲醇分压降低,甲醇转化率下降,产物丙烯/乙烯质量比(P/E比)增加,丙烯在甲醇分压为33 kPa时达到最高值,而当分压极低时,催化剂快速失活。从转化率、丙烯选择性、P/E比以及低碳烯烃产物选择性等多方面综合考虑,甲醇转化制丙烯的反应温度优选470℃,并建议甲醇分压为33 kPa。     

稀土氧化物上SO2和NO的催化还原V.以城市煤气作还原剂同步脱硫脱氮

考察了氧化镧作催化剂在单独脱硫和同步脱硫脱氮反应中,城市煤气替代CO作还原剂的可行性。结果表明在La2O3催化剂上,不仅可以获得较高的单独脱硫效率,而且也有较高的同步脱硫脱氮转化率。煤气中的CH4在任何情况下都不参与反应,而其中的H2视反应温度的高低而不同程度地参与反应。当反应温度低于600℃时,H2不参与反应。研究表明适宜的反应温度为500℃~550℃,此时副产物H2S和COS的生成均为最小,可使SO2和NO的转化率分别大于87%和97%,元素S的选择性接近100%。     

焦炉煤气化学链置换燃烧模拟研究

以焦炉煤气(COG,coke oven gas)为燃料,研究了CaSO4载氧体在燃料反应器(FR,fuel reactor)内的还原性,从原子层面对反应路径进行了探讨分析。当反应温度较低时(100~300℃),主要发生CO-H2甲烷化反应和CH4-CaSO4热化学硫酸盐还原反应,CaCO3与H2S是该温度范围内的主要产物。当反应温度较高时(400~1000℃),CaSO4与CO、H2和CH4之间的还原反应占据了主导地位,CaS、H2O和CO2是该温度范围内的主要产物。当反应温度进一步升高时(1000~1400℃),CaSO4与CaS发生固固反应生成大量的副产物SO2和CaO。温度和压力对产物中硫化物的分布有很大影响,在反应温度为1000℃,压力为0.1 MPa时,焦炉煤气的燃烧反应进行的很充分,但是反应在加压条件下进行时,CaSO4、CaS和H2S含量会有明显的下降,而SO2含量有一定程度的增加。     

甲醇的魅力(下)——最简单的醇类有望成为大有前途的原料和燃料

甲醇作为燃料的可能性已被确认,但现在的问题是如何制造它.以前,甲醇是通过部分氧化煤或天然气得到合成气而生产的,合成气是H2、CO和CO2的混合物,这些组分可以反应生成甲醇,副产物为CO20     

化学链燃烧钙基载氧体CaSO4与CO在不同温度下的反应行为

基于热重和红外联用进行等温实验,探讨了化学链燃烧载氧体CaSO4在CO气氛下的还原反应特性.研究发现:温度对CaSO4还原反应历程和速率有显著的影响,在10%CO气氛下,温度低于900℃时,发生单一反应,CaSO4的还原产物只是CaS,气相产物为CO2;当温度高于950℃后,发生平行反应和连串反应组合成的多重反应,固体产物为CaS和CaO,而产物气中除了有CO2,还存在SO2和COS,且气相硫化物的析出以COS为主;随着反应温度的升高,CaSO4与CO反应速率显著增加,而目标产物CaS在固体产物中所占的摩尔分数呈下降趋势;基于钙基载氧体化学链燃烧中燃料反应器温度不宜高于950℃.     

TS-1/H2O2催化氧化体系在超临界CO2中应用的研究

对超临界CO2条件存在时TS-1／H2O2氧化体系进行了研究。所选择的反应分别是苯乙烯的氧化和叔丁醇的氧化。实验结果表明,TS-1可以在超临界CO2中保持较高的活性和选择性,但反应结果都不如无超临界CO2存在时的情况。其中对于苯乙烯氧化反应,H2O2的有效利用率可以达到78．4％以上;而对于叔丁醇氧化,H2O2的利用率则较低。经分析认为,这是由于H2O2水溶液和超临界CO2的相容性较差,在TS-1／H2O2氧化体系中引入超临界CO2条件造成负面影响。     

H_2促进C_3H_6在Ag/Al_2O_3催化剂上SCR-NO的研究

少量H_2可以增强丙烯在Ag/Al_2O_3催化剂上选择性还原NO的活性,降低NO的起燃温度(<100℃),在2个温度区间内NO转化率比较高:第1个是低温区间80¹80℃,第2个是250180℃,第2个是250⁵00℃,在这两个温度区间内NO的转化率没有太大变化,在中间温度区间内比较低,低温区间NO转化率较高是由于H_2的还原作用,当温度高于180℃时C_3H_6起主要作用。N_2和NO_2是主要的竞争产物低温时有NO_2形成,当温度在140℃左右和高于380℃的时候对N_2的选择性非常高,在200℃和260℃时NO_2的浓度77×10500℃,在这两个温度区间内NO的转化率没有太大变化,在中间温度区间内比较低,低温区间NO转化率较高是由于H_2的还原作用,当温度高于180℃时C_3H_6起主要作用。N_2和NO_2是主要的竞争产物低温时有NO_2形成,当温度在140℃左右和高于380℃的时候对N_2的选择性非常高,在200℃和260℃时NO_2的浓度77×10^(-6)(-6)⁸3×1083×10^(-6)占主要产物,165(-6)占主要产物,165⁵00℃时仅仅检测到N_2O_2×10500℃时仅仅检测到N_2O_2×10^(-6),对H_2-C_3H_6-SCR的反应体系,500℃时比较高的空速条件下会生成48×10(-6),对H_2-C_3H_6-SCR的反应体系,500℃时比较高的空速条件下会生成48×10^(-6)NH_3并增加了CO/CO_2比值。氧气和催化剂表面NO_2等中间体与还原剂之间存在着竞争反应,但是仍能被还原成N_2,这些中间产物在低温时容易被H_2还原而在高于180℃时易被C_3H_6还原。通过XPS分析可以发现,部分活性组分Ag在载体Al_2O_3上即使在低温条件下也非常不稳定,由于不同价态银物种相互作用使催化剂在不同温度区间内活性不同选择性也有很大差别,在C_3H_6-SCR反应之后Ag(-6)NH_3并增加了CO/CO_2比值。氧气和催化剂表面NO_2等中间体与还原剂之间存在着竞争反应,但是仍能被还原成N_2,这些中间产物在低温时容易被H_2还原而在高于180℃时易被C_3H_6还原。通过XPS分析可以发现,部分活性组分Ag在载体Al_2O_3上即使在低温条件下也非常不稳定,由于不同价态银物种相互作用使催化剂在不同温度区间内活性不同选择性也有很大差别,在C_3H_6-SCR反应之后Ag⁺和Ag_n+和Ag_n^(δ+)物种随之出现,当在反应气中通入H_2以后金属纳米Ag单质也会生成。XRD结果也同样表明,在H_2-C_3H_6-SCR反应后有大于5 nm的Ag纳米粒子形成。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

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.     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

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.