苯和碳九芳烃烷基转移催化剂的工业侧线试验

对苯和碳九芳烃烷基转移催化剂进行了工业侧线试验,考察了不同工艺条件下的催化剂性能.结果表明,适宜的反应条件为反应温度360～380 ℃,反应压力2.0～3.0 MPa,质量空速1.0～2.0 h-1,氢烃物质的量之比为 4～6,原料中苯与C9+A质量之比为(30∶70)～(50∶50),该条件下,催化剂活性较高,反应的总转化率和总选择性分别为45%和95%左右.1 100 h的稳定性试验结果表明,催化剂床层入口温度仅提高5 ℃而总转化率和总选择性基本不变,说明该催化剂的稳定性好.     

新型甲苯择形歧化催化剂工艺条件优化

以纯甲苯为原料,分别考察了温度、压力、空速和氢烃比等工艺条件对新型甲苯择形歧化催化剂性能的影响。结果表明:在新型甲苯择形歧化催化剂作用下,反应温度提高或反应压力增加,甲苯转化率增加,对二甲苯选择性下降;反应空速提高,甲苯转化率降低,对二甲苯选择性增加;氢烃比增加,甲苯转化率降低,对二甲苯选择性没有明显的变化。该催化剂稳定性良好,在反应温度445℃,压力2.0 MPa,氢烃分子比2.0和空速4.0 h~(-1)的条件下进行1 000 h催化剂稳定性试验,甲苯转化率可达30.2%,对二甲苯选择性可达94.3%。     

SD-01催化剂在扬子石化公司的工业应用

SD-01甲苯择形歧化催化剂在扬子石化公司67万吨/年甲苯择形歧化装置上工业应用成功并稳定运行,前6个月运行结果为：甲苯转化率为29%,对二甲苯选择性为89%;苯与C₈芳烃收率为97 %,苯冰点5.47 ℃。空速、反应温度、反应压力、氢烃比等工艺参数对装置稳定优化运行有重要影响。     

HLD-002甲苯歧化与烷基转移催化剂工业侧线试验

开展了HLD-002甲苯歧化与烷基转移双功能催化剂工业侧线试验,通过考察反应压力、氢气纯度和氢烃分子比等工艺参数对HLD-002甲苯歧化与烷基转移催化剂反应性能的影响,得到HLD-002催化剂运行的较佳工艺条件。HLD-002催化剂在工业侧线装置上长周期运行结果表明,在高空速条件下(重时空速3.5 h-1),能保持较高的总转化率(45%以上)和总选择性(88.5%以上)并具有较高的重芳烃处理能力,高空速下C10重芳烃转化率高达63%以上。通过复合床工艺优化,HLD-002甲苯歧化与烷基转移催化剂在高空速下能保证产品苯纯度合格。工业侧线试验结果表明,HLD-002催化剂满足大规模工业应用的要求。     

β沸石催化剂上甲苯歧化及与1,2,4-三甲苯烷基转移反应研究

对在液固相连续反应装置上以β沸石为催化剂进行甲苯歧化及甲苯与1,2,4-三甲苯烷基转移生成二甲苯及苯的反应进行了研究，并对影响反应的因素如温度、压力、氢气用量、反应物空速等进行了探讨。结果表明，该催化剂对上述反应有较好的催化作用。对于甲苯歧化反应，在温度280 ℃，压力3.5 MPa，甲苯重量空速4h^－1，n_氢/n_甲苯＝4∶1时，甲苯转化率为47.26%，苯与二甲苯总选择性为93.50%。对于甲苯与三甲苯的烷基转移反应，当进料比n_甲苯/n_三甲苯=2，温度280 ℃，压力3.5 MPa，总重量空速4 h^－1，n_氢/n_烃=2∶1时，总转化率为47.17%，二甲苯选择性为83.25%，二甲苯收率达39.26%。     

降低汽油苯含量的苯烃化技术试验研究

对于苯体积分数为1%～2%的汽油,采用苯烃化技术可显著降低汽油中的苯含量.在小型固定流化床试验装置上,采用自制的催化剂,考察了汽油苯烃化反应的影响因素并确定了优化的反应条件:反应温度250℃,反应压力1 MPa(表压),汽油空速1.0 h-1,烯/苯摩尔比6～7.在优化的反应条件下,汽油中的苯含量可降低45%.     

烯烃歧化制备α-烯烃新方法研究

制备了一种负载型Re基催化剂Re2O7/γ-Al2O3,用于直链内烯烃与乙烯歧化制备α-烯烃。结果表明,以C11～C12直链内烯烃为原料,反应温度60℃,反应体积空速1 h-1,反应压力3 MPa的条件下,C11～C12烯烃的单程转化率达到90.0%,歧化选择性达到85.98%。     

Pd-Pb双金属催化剂上甲苯歧化与烷基转移反应性能

为提高甲苯歧化与烷基转移生成苯和二甲苯反应的收率,采用了ZSM-12分子筛负载钯和铅的双金属甲苯歧化与烷基转移催化剂,在连续操作的小型固定床反应器中考察了钯金属负载量、钯-铅物质的量比、反应条件对反应性能的影响。结果表明:引入钯金属能提高重芳烃转化率,同时也加剧了苯环加氢副反应;适当降低钯金属负载量、采用钯-铅双金属体系能有效抑制芳烃加氢副反应,优化催化剂整体反应性能;提高反应温度、降低氢气纯度及反应压力有利于抑制加氢副反应,改善催化剂反应性能。基于钯含量为0.2%,Pb/Pd比为3的双金属催化剂体系,在原料组成苯与碳九及其以上重芳烃的质量比为30:70,反应温度390℃,反应压力2.5 MPa,进料空速4.0 h-1,氢烃比2.0的较佳条件下,甲苯的转化率为21.7%,重芳烃转化率61.6%,二甲苯的质量收率达36.2%,苯的纯度为99.5%,表现出了较高的重芳烃处理能力及二甲苯收率。     

负载型骨架镍催化剂催化轻质石脑油加氢脱苯

针对当前对溶剂油中苯含量的严格要求,研究负载型骨架镍催化剂在轻质石脑油加氢脱苯反应过程中的加氢性能,并考察反应温度、反应压力、空速以及氢油体积比等对轻质石脑油加氢脱苯反应的影响。结果表明,骨架镍催化剂具有较高的低温加氢活性,适宜条件为:反应温度140℃,反应压力0.2 MPa,空速2 h~(-1),氢油体积比120,此条件下,苯转化率达到99%。     

甲苯歧化与烷基转移催化剂的实验室评价及工业应用

以丝光沸石为主体制备的HAT-096甲苯歧化与烷基转移催化剂，在空速1.7～2.0h^-1、3.0MPa、n(氢)n(烃)=6∶1条件下实验室评价1 000 h，转化率大于48%、选择性大于94%。该催化剂在210 kt·a^-1工业装置上运行9个月后，在空速1.6 h^-1下进行72 h标定，平均转化率大于48%，选择性大于95%。该催化剂已运行6年多未进行再生，表明催化剂稳定性能良好，适宜于长周期运行。     

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.     

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.     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.