栲胶脱硫工艺中含硫副产物生成的热力学分析

采用热力学方法研究了栲胶脱硫工艺中HS-与钒的反应机理和副反应的吉布斯自由能变。研究结果表明,脱硫液中五价钒主要是以HV2O3-7形式存在,四价钒主要是以V4O2-9形式存在。HS-与五价钒反应可瞬间生成多硫离子S2-x,然后S2-x转化为单质硫。在栲胶脱硫工艺的操作温度下,HS-和S2-x与氧气作用均可生成副产物,但S2-x比HS-活泼,更易发生副反应,且S2-x中x的值越小越活泼。在S2-x转化为副产物S2O2-3的过程中,温度越高,越有利于副反应的发生。对栲胶脱硫工艺而言,S2-x是生成副产物的活性中间产物,因此,栲胶脱硫液在进入再生系统前,应使S2-x尽可能多地转化为S8结构。     

预硫化对异戊二烯选择加氢镍基催化剂性能的影响

对7.5%Ni/(κ+θ+α)-Al2O3催化剂进行预硫化处理,研究硫化液种类和浓度、硫化度、硫化温度等因素对催化性能的影响,旨在保证催化剂加氢活性的同时,提高催化剂对单烯烃的选择性。通过对硫化条件进行优化,使单烯选择性从0增加至93%。通过对CS2催化剂中毒机理的考察发现,CS2在低温下极易使催化剂失活。导致催化剂失活的因素有2个:其一是低温下CS2与催化剂活性中心反应形成金属硫化物;其二是CS2在催化剂表面的物理吸附。     

栲胶脱硫工艺副反应分析及硫膏的提纯

栲胶脱硫工艺是一种脱除各种燃料气中H2S气体的湿法脱硫工艺。本文通过分析工业栲胶脱硫废液及硫膏中的组分含量,探讨了栲胶脱硫工艺的副反应及硫膏提纯的必要性。研究表明,在栲胶脱硫过程中,不可避免地发生着一些副反应,并生成副产物NaSCN、Na2S2O3、NaHCO3及Na2SO4。在这些副产物中,NaSCN和Na2S2O3的含量较高,生成NaSCN和Na2S2O3的反应是脱硫过程的主要副反应。副产物的生成是造成碱耗增加的主要原因之一。在硫膏中,单质硫的含量最高,约占硫膏总量的一半。甲苯是单质硫最合适的提取剂,硫膏经甲苯提纯后,单质硫的纯度可达95%以上。     

预硫化耐硫变换催化剂的研制

钴钼系耐硫低变催化剂已广泛应用于中、小氮肥厂 ,催化剂使用前必须进行高温硫化 ,常用CS2 和 H2 S作为硫化剂现场进行硫化。但现场硫化时常常出现因操作不当引起催化剂超温 ,损坏催化剂的活性 ,严重时整炉催化剂报废 ;其次 CS2易燃 ,硫化过程中经常会出现放空管或硫化罐着火等不安全因素 ;再者 CS2 和 H2 S有剧毒 ,特别是 CS2 ,它可以通过呼吸道及皮肤损害人体机能(对操作人员造成较大危害 ) ;此外 ,现场硫化不仅耗费时间、煤气、电力、硫化剂等 ,并且一般需 2～ 3天才能转入正常生产 ,因此 ,研制一种新型换代的耐硫低变催化剂是很有…     

正丁醇脱氢硫化制备噻吩催化剂的优选

噻吩是一种重要的有机物,噻吩及其衍生物有着广泛的用途.采用正丁醇与二硫化碳混合进料脱氢硫化制备噻吩,主要探讨了催化剂体系K2CO3-Cr2O3/γ-Al2O3,对活性组分的负载量进行了优选.研究结果表明,在n(CS2)n(正丁醇)=21、空速1 h-1、温度400℃、11%K2CO3-15%Cr2O3/γ-Al2O3反应条件下,催化剂在正丁醇合成噻吩的过程中表现较好,目标产物噻吩的转化率较高.     

气氛效应对铁锰基吸附剂中高温煤气脱硫性能的影响

考察了H2、CO、CO2和H2O等单独或同时存在下,气氛对铁锰基吸附剂硫化性能的影响。结果表明:吸附剂中的Mn2O3、Fe2O3较易被H2或CO还原为与H2S反应能力较佳的Mn3O4、Fe3O4,由于H2与吸附剂中的晶格氧结合,从而改变金属氧化物的价态,并改善吸附剂的孔隙率,有利于中高温煤气中H2S的脱除;但H2与CO同时存在时,因还原性的增强和CO歧化反应产生积炭,又会严重破坏吸附剂的结构。CO2与H2S在吸附剂表面上发生竞争吸附,不利于吸附剂上硫化反应的进行;但CO2能够改善CO歧化反应生成积炭和碳化铁破坏吸附剂结构稳定性的行为。H2O是硫化反应产物之一,对吸附剂的硫化性能具有抑制作用,但其作用可以通过水煤气变换反应减弱。     

粘胶纤维生产废气中CS2、H2S的处理

介绍了在粘胶纤维生产中CS2参与纤维素反应的化学反应机理及副产物H2S的产生，以及对CS2和H2S的处理回收方法。     

日研制成功新型催化剂

日本政府所属的工业研究院研制成功一种能把 CO_2转化为可用作工业原料 CO 的硫化钨催化剂。这种催化剂是在400℃下还原四硫代钨酸铵制得的。这种催化剂的转化性能优于二硫化钨或钨催化剂,CO_2转化率可达到99.9%,而且不产生任何副产物。生成的 CO 可用作生产甲醇、甲醛以及乙二醇的原料。新催化剂的研制成功有助于碳循环技术的开发,从而可为防止全球性的气候变暖开辟一条道路。全世界每年有200亿 tCO_2排入大气,引起全球性温度升高。     

水压法CS2贮罐的设计及应用

在低变触媒失活后，每次都要进行原始硫化或再硫化，以期达到理想的效果。但在使用液体硫化剂（CS2）进行低变触媒硫化时，95％的企业采用氮气气压作为动力推进CS2进行硫化。     

TSS-1精脱硫剂新技术在食品CO2装置中的应用

介绍了TSS-1精脱硫剂在食品CO2装置中精脱CS2新技术的工业应用情况,解决了食品CO2行业中CS2净化的技术难题,为保护高效催化剂及产品质量提供了有效保证.     

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。