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对SiO2及其用碱土金属、稀土金属修饰的混合氧化物催化剂进行了表征,并研究了其对甲醛、乙醛缩合生成丙烯醛的催化性能,详细考察了甲醛、乙醛的摩尔比;反应温度;投料速度对乙醛的转化率和生成丙烯醛的选择性等的影响。 相似文献
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一、前言一九七六年四月,石化部在苏州召开“电解银代替浮石银催化氧化生产甲醛”会议。石化部要求全国生产甲醛各工厂立即行动,使用、推广电解银这一新技术,为国家节省原材料,生产更多化工产品。我厂是一九六九年开始生产甲醛,也用浮石银氧化乙醇为乙醛,对浮石银缺点早有 相似文献
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研究了超高效液相色谱用于卷烟包装纸中甲醛和乙醛含量测定方法。甲醛和乙醛通过2,4-二硝基苯肼衍生化后,以0.5%甲酸水溶液-乙腈(体积比为65∶35)为流动相,在Waters BEHShield RP18(1.7μm,2.1 mm×50 mm)色谱柱上分离,二极管阵列检测器检测,检测波长360 nm。甲醛和乙醛在5 min内即可完全分离,方法具有较好的重现性和线性关系,相关系数均达到0.999 9,加标回收率甲醛为97.9%,乙醛为95.5%;用于卷烟包装纸中甲醛和乙醛的快速测定,结果满意。 相似文献
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聚乙烯醇缩甲乙醛制备条件的研究 总被引:2,自引:0,他引:2
研究了用聚乙烯醇,甲醛,乙醛为原料,在盐酸催化作用下,制备聚乙烯醇缩甲乙醛的各种影响因素,探索出了原料用量比,反应时间,反应温度,溶液pH、PVA浓度、加料方式等最佳反应条件。 相似文献
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以甲醛、乙醛、烧碱为原料合成季戊四醇,通过正交试验,考察了各种工艺条件对合成单季戊四醇收率的影响。确定的优惠工艺条件为:甲醛与乙醛的分子比6.0,碱与乙醛的分子比1.20,甲醛溶液浓度12.0%,反应温度20℃,反应时间120min。在优选的工艺条件下,单季戊四醇的收率可达94.4%。 相似文献
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The chemical polymerizations of pyrrole in the presence of acetophenone and formaldehyde, cyclohexanone, acetaldehyde, and formaldehyde, cyclohexanone and formaldehyde, cyclohexanone, resorcinol, and formaldehyde, cyclohexanone and lignosulfonate formaldehyde, and cyclohexanone, pyrrole, and formaldehyde were accomplished with Ce(IV) salt in acetonitrile solutions. The roles of the resin type, the addition order of the reactants, and the concentrations of the pyrrole and resin on the solubility and conductivity of the resulting products were investigated. The cyclohexanone–acetaldehyde–formaldehyde resin/polypyrrole copolymer had the highest solubility in dimethylformamide. The conductivity and solubility of the copolymers could be controlled by the Ce(IV)/pyrrole/resin molar ratio. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 618–624, 2005 相似文献
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Technical lignin and condensed tannins have been combined with soy flour as model of no-added-formaldehyde adhesive binders for veneer wood products to understand their impacts on volatile organic compounds (VOCs) produced during panel manufacture. VOC emissions captured on manufacturing lauan hardwood plywood at 170?C were dominated by acetaldehyde, hexaldehyde, acetone, and terpenes in both the condensate and gaseous fractions of press emissions. Other aldehydes including formaldehyde, valeraldehyde, and propionaldehyde were produced in relatively lower quantity during panel manufacture. Compared to using soy flour alone, lignin, and tannin reduced the formaldehyde and acetaldehyde contents in press emissions. These reductions in VOCs had a dependency on adhesive resin pH with an alkaline formulation proving to also decrease longer chain aldehydes such as valeraldehyde and hexaldehyde. Chamber testing plywood panels found the composition of VOC emissions initially released from panels to be prominent compounds released in press emissions formed on panel manufacture. Use of soy flour alone as binder produced relatively high acetaldehyde emissions from panels, whereas incorporating lignin and tannin with soy flour as adhesive binders reduced both acetaldehyde and formaldehyde emissions from panelboards post-manufacture. 相似文献
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主要研究了甲醛、乙醛和苯在有机硅烷KH560和1706改性活性炭(AC)表面的脱附活化能,并通过透过曲线实验测定了不同湿度对三者在改性活性炭上吸附的影响,最后用光电子能谱(XPS)分析材料表面的亲水基团和憎水基团比例的变化。结果表明,采用有机硅烷改性活性炭可提高材料的憎水性,在较高湿度下(RH60%),三者在未改性活性炭固定床穿透时间减少得最多,1706/AC固定床次之,KH560/AC固定床最小;程序升温脱附(TPD)实验表明,用有机硅烷改性活性炭可以削弱水和活性炭表面的结合力,增强与甲醛、乙醛和苯的结合力。通过XPS分析,与未改性活性炭相比,经有机硅烷改性的活性炭,其憎水性得到提高。 相似文献
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Marina C. Rodrigues Lílian L.N. Guarieiro Manuela P. Cardoso Luiz Souza Carvalho Gisele O. da Rocha Jailson B. de Andrade 《Fuel》2012,92(1):258-263
The increasing of both industrialization and motorization of the world has led to a sharp rise in the demand for fossil fuels. Concern about the environmental impact caused by burning of these fuels has involved researchers that became engaged in assessing the damages of pollution not only to environment, but also to human health. In this study, carbonyl compounds (CC) were measured in vapor samples from a place impacted by heavy-duty vehicles (Bus Station) fuelled with diesel/biodiesel fuel blend (B5) in Salvador, Brazil. Among them, formaldehyde, acetaldehyde and propanone were the most abundant quantified compounds. Concentration levels (ppbV) for major CC detected during the sampling period ranged from 28.45 to 287.3 (formaldehyde), 24.91 to 171.3 (acetaldehyde) and 5.835 to 72.29 (propanone). The obtained data in this site was compared to formaldehyde and acetaldehyde concentrations found in other sites impacted by heavy-duty vehicles fuelled with pure diesel and diesel/biodiesel blends. All data were used to make a possible correlation with formaldehyde/acetaldehyde ratio and the relationship with the kind of fuel used by these vehicles. PCA was used to verify possible grouping among 19 sites impacted by heavy-duty vehicles and showed two major groups, one characterized by being strongly impacted and the other with a low contribution of heavy-duty vehicles. Thus, the addition of higher concentrations of biodiesel to diesel showed an improvement in the carbonyl concentration profile at places with high circulation of heavy-duty vehicles, which had similar profile to those found for sites less impacted by these kind of vehicles. 相似文献
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We report 4-h average concentration data for acetone, formaldehyde, acetaldehyde, and carbon monoxide measured in downtown Denver, Colorado, USA from January through December 1993. The correlations between these carbonyl compounds and CO measurements suggest that motor vehicles are a significant source for all three carbonyls, particularly during the winter. The diurnal character of the concentrations of formaldehyde and acetaldehyde suggests that there is at least a small net photochemical source for these compounds during the summer. The diurnal character of the acetone concentration suggests that there is a significant net photochemical source for acetone during the summer. An analysis of the initial photochemical production and loss processes for these carbonyls under typical atmospheric conditions suggests that the production and loss processes for formaldehyde nearly balance. This same analysis for the other carbonyls suggests that there should be a large net photochemical source for both acetaldehyde and acetone. Such a large photochemical source is not observed for acetaldehyde. Acetone is relatively unreactive in the atmosphere on a timescale of urban or regional interest. Thus, atmospheric measurements of acetone concentrations may serve as a useful indicator of the photochemical age or degree of photochemical processing of an air mass. 相似文献