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1.
研究了γ-十一内酯合成过程中包含可逆的主反应和丙烯酸聚合副反应的宏观动力学,为提高反应选择性提供了动力学依据。实验在连续操作的釜式反应器中进行,考察不同温度、不同进料流量条件下反应速率,利用实验数据对模型进行参数拟合,得到主反应和副反应动力学参数,经统计检验和残差分析表明,所建立的动力学模型可靠,可用于宏观描述该反应。研究结果证明:提高反应温度,降低丙烯酸浓度有利于提高主反应选择性、提高γ-十一内酯收率。  相似文献   

2.
对钛硅分子筛(TS-1)催化环己酮氨肟化反应进行了研究。根据该反应体系中环己酮可能部分吸附在TS-1分子筛活性中心上与氨发生亚胺机理,未被吸附的环己酮和羟胺中间体发生羟胺机理(双机理),建立了氨肟化反应以及该反应体系中过氧化氢分解的动力学方程,结合实验数据,对参数进行了估算及统计检验,对氨肟化反应和过氧化氢分解的动力学模型的计算值与实验值进行了比较,结果表明该模型能真实反映TS-1分子筛催化环己酮氨肟化的反应规律。同时,对双机理模型中各机理也进行了模拟计算,结果表明,双机理模型中的亚胺和羟胺机理在反应体系中发生的几率跟反应温度有很大关系。另外,过氧化氢分解动力学模型只适用于该反应体系。  相似文献   

3.
催化汽油氧气氧化脱硫的反应动力学   总被引:1,自引:0,他引:1       下载免费PDF全文
以氧气作为氧化剂,开展催化汽油氧化萃取脱硫实验及氧化动力学研究。实验结果表明,氧气氧化萃取脱硫对催化汽油具有较好的脱硫效果;随着相转移催化剂用量增加、温度提高、氧气分压增大、时间延长、水与汽油体积比增大,汽油脱硫率持续提高,而汽油收率呈现降低的变化趋势。根据反应动力学方程和萃取相平衡原理,确定了脱硫率和汽油收率模型,并开展模型参数估值、统计检验和预测分析。研究结果显示,所建模型具有较高的模拟精度,预测结果与脱硫实验结果的变化趋势相同。  相似文献   

4.
为实现碱减量废水残渣有效利用,对碱减量废水残渣甲酯化反应条件与反应动力学规律进行了系统考察。论文首先考虑洗涤干燥等预处理方法对碱减量废水残渣组成的影响,然后通过改变醇酸比、初始水分含量及反应温度条件,进行了碱减量废水残渣甲酯化反应动力学实验研究。结果表明,预处理可有效去除残渣中的无机盐杂质提高对苯二甲酸纯度,但预处理会明显降低后续残渣甲酯化产物对苯二甲酸二甲酯(DMT)的收率以及对苯二甲酸(TA)甲酯化反应的转化。TA甲酯化两步反应均对温度敏感,采用典型的可逆平衡反应模型对实验数据进行拟合,得到动力学模型参数,并在此基础上对动力学模型进行检验,结果表明所建立的动力学模型是可靠的,能很好的预测各组分的浓度。研究所得可为碱减量废水残渣甲酯化工艺放大与设计提供依据。  相似文献   

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为考察神华上湾煤的直接液化性能及反应动力学,以加氢蒽油-洗油混合油作为溶剂、负载型FeOOH作为催化剂,在0.01 t·d-1煤直接液化连续实验装置上考察了不同反应温度(435~465℃)、不同停留时间(7~110 min)下液化产品组成的演变规律。研究发现,随着煤的裂解及加氢反应的进行,煤及沥青类物质(PAA)收率不断减小,重质液化产物逐步向轻质液化产物转化。当反应温度为455℃、停留时间为90 min时,煤转化率为90.41%(质量分数(,油收率为61.28%(质量分数(。随着反应条件进一步苛刻,油收率下降。基于上湾煤直接液化反应特性及其产物收率变化规律建立了11集总煤直接液化反应动力学候选模型,以BFGS优化算法对实验数据搜索、选优,确定了动力学模型参数。检验结果表明所建立的动力学模型可用于恒温阶段直接液化行为的模拟计算。  相似文献   

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为考察神华上湾煤的直接液化性能及反应动力学,以加氢蒽油-洗油混合油作为溶剂、负载型FeOOH作为催化剂,在0.01 t·d~(-1)煤直接液化连续实验装置上考察了不同反应温度(435~465℃)、不同停留时间(7~110 min)下液化产品组成的演变规律。研究发现,随着煤的裂解及加氢反应的进行,煤及沥青类物质(PAA)收率不断减小,重质液化产物逐步向轻质液化产物转化。当反应温度为455℃、停留时间为90 min时,煤转化率为90.41%(质量分数),油收率为61.28%(质量分数)。随着反应条件进一步苛刻,油收率下降。基于上湾煤直接液化反应特性及其产物收率变化规律建立了11集总煤直接液化反应动力学候选模型,以BFGS优化算法对实验数据搜索、选优,确定了动力学模型参数。检验结果表明所建立的动力学模型可用于恒温阶段直接液化行为的模拟计算。  相似文献   

7.
提出了苯酚、甲醛经酸性离子液体[Hmim]HSO4催化的反应机理和三步骤反应模式,推导出了其反应动力学方程。结果表明:反应速率常数与反应温度和离子液体浓度有关。在酚、醛物质的量比6∶1和充分搅拌条件下,在反应温度80~100℃及酸、醛物质的量比2∶1~1∶2范围内,采用滴加甲醛方式,进行了双酚F合成反应的动力学实验,实验结果与动力学模型拟合良好。在n(酚)∶n(醛)∶n(酸)为6∶1∶1及80~90℃最佳反应条件下,双酚F收率可达79%以上,反应表观活化能Ea=19.92 kJ/mol。  相似文献   

8.
针对传统羟胺盐生产工艺中存在的工艺路线复杂、副反应多、三废多、后处理成本高及肟水解平衡转化率低等技术难题,通过计算不同硫酸浓度下酮肟水解在一定转化率下理论剩余水量及生成硫酸羟胺质量,并结合常压下硫酸羟胺在水中的溶解度的测定结果,提出将反应—精馏与反应—结晶两种反应分离技术耦合用于酮肟水解制备硫酸羟胺工艺,通过将产物硫酸羟胺以及副产物酮的连续原位移出以提高反应转化率,同时避免反应液因黏度过高而影响传质和传热,防止局部过热,避免副反应发生,实现高浓度硫酸反应体系下制备硫酸羟胺,可实现硫酸羟胺生产行业进一步节能减排。研究验证了不同酸肟比及初始加入硫酸浓度下改进后工艺的可行性,当酸肟比为0.5:1、初始加入硫酸浓度为40%~60%(wt)时,该工艺硫酸羟胺单次收率均高于91%;实验结果证明该工艺具有良好的工业化前景。  相似文献   

9.
郭建法  王涛 《世界农药》2022,(11):36-40
为降低肟菌酯生产成本,对其合成工艺进行优化。以溴化物和间三氟甲基苯乙酮肟为原料,缩合反应合成肟菌酯,研究物料配比、反应温度、溶剂种类等对反应收率与含量的影响。采用“一锅投”方式,以三辛基甲基氯化铵为催化剂,甲基异丁基酮为溶剂,碳酸钠为缚酸剂,优化条件下,肟菌酯收率83.5%,含量98.3%。该合成方法收率高,工艺简单,适合工业化开发。  相似文献   

10.
研究了以氯气和2,4二-氯甲苯为原料制取2,4二-氯亚苄基二氯,讨论了2,4二-氯甲苯侧链光氯化反应温度对产物收率的影响;用气相色谱仪分别测定了在343 K、373 K及403 K 3个不同温度下反应体系中各组分摩尔分数随反应时间的变化;导出氯化反应过程的动力学模型为dxC/dt=-kxC,3个不同温度下k值分别为0.096、0.120、0.192 h-1。实验数据与动力学模型拟合的结果相吻合。  相似文献   

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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.  相似文献   

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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.  相似文献   

15.
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.  相似文献   

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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.  相似文献   

19.
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.  相似文献   

20.
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。  相似文献   

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