Alkylation of aldehydes with methanol over titanium oxide catalysts

The methylation of various aldehydes, such as acetaldehyde, propionaldehyde, and phenylacetaldehyde over titanium oxidesupported vanadium oxide was studied under atmospheric pressure and temperatures of 250–400°C. The catalyst properties of titanium oxide can be enhanced only by addition of a fairly small amount of vanadium. High-temperature treatment transforms titanium oxide, the support, from anatase to rutile, which causes the catalysts to lose their catalytic properties. The reactivity of these can be ranked in the following order: acetaldehyde > propionaldehyde > phenylacetaldehyde. The steric effect of the substituted groups in propionaldehyde or phenylacetaldehyde may prevent self-condensation to form oligomers and to give a high selectivity of alkylated products.     

Chemical and Chromatic Bases for Preferential Visiting By the Cabbage Butterfly, Pieris rapae, to Rape Flowers

Scent and coloration of corolla were examined as floral attributes responsible for preferential visiting by the cabbage butterfly, Pieris rapae, to rape flower, Brassica rapa. Floral volatile components that release the flower-visiting behavior of the butterfly were identified by chemical analyses, electroantennography (EAG), and two behavioral bioassays: proboscis extension reflex (PER) in response to odor and attraction to artificial flowers. GC and GC-MS analyses of the headspace volatiles from the flowers revealed the presence of six aromatic compounds, benzaldehyde, phenylacetaldehyde, benzyl alcohol, 2-phenylethanol, phenylacetonitrile, and indole in decreasing order of quantity. Of these, phenylacetaldehyde elicited the highest response in the PER assay. While benzyl alcohol, 2-phenylethanol, benzaldehyde, and phenylacetonitrile evoked moderate responses, the PER-eliciting activity of indole was very weak. In two-choice behavioral bioassays, artificial flowers scented with any one of these PER-active compounds attracted significantly more butterflies than control (unscented) flowers, whereas those treated with indole were almost inactive. The EAG activities of the six chemicals were not high and were about the same at a low dose (1 g), but phenylacetaldehyde elicited a much stronger response from both sexes at higher doses (10 and 100 g). An overall profile of EAG responses at a dose of 100 g was analogous to that of PER performance, suggesting that floral volatiles may be involved in close-range location or recognition of flowers rather than long-range attraction. By spectroscopic and UV-photographic examinations of rape flower, the central part of the corolla was found to absorb UV rays in marked contrast to the other parts, which reflected near-UV rays (_max = 350 nm). This indicates that the flower is endowed with a conspicuous nectar guide that is probably an important visual stimulus for attracting foraging adults of P. rapae. Consequently, the present findings strongly suggest that this elaborate pollination strategy of rape flower, characterized by its good combination of olfactory and visual attractiveness, accounts for preferential visiting by the cabbage butterfly to the flower.     

苯乙炔烯基化反应制备缩醛的研究

在氢氧化钾-二甲基亚砜(KOH-DMSO)强碱性双向催化体系中,被活化的醇与苯乙炔发生烯基化反应,进而与醇生成相应的缩羰类化合物,适宜的催化剂配比为4．0 g KOH需要25．0 g DMSO。制备苯乙醛缩二甲醇、苯乙醛缩乙二醇、苯乙醛缩1,2-丙二醇的最佳反应时间分别为30,50,60 min,收率分别为85．7％, 80．3％,79．1％。该法工艺简单,收率优于甲醇钠体系。     

Kairomone from dandelion,Taraxacum officinale,attractant for scarab beetleAnomala octiescostata

The attraction of the scarab beetleAnomala octiescostata to dandelion,Taraxacum officinale, was demonstrated to be chemically mediated by a mixture ofcis-3-hexenyl acetate, benzaldehyde, phenylacetaldehyde, benzyl alcohol, phenethyl alcohol, phenylacetonitrile, and benzyl benzoate, in the ratio 4:8:14:3:5:19:11. Combination of the synthetic kairomone and sex pheromone (buibuilactone + japonilure, 8:2), significantly increased the total catches ofA. octiescostata. Catches of male (but not female) beetles were significantly higher with the kairomone-pheromone blend than with kairomone alone. The synergistic effect of the kairomone from dandelion on the attractiveness did not significantly differ from that of a food-type lure, anethol, geraniol, and phenethyl propionate (9:0.5:0.5). The latter combined with the synthetic sex pheromone resulted in better attraction of female (but not male)A. octiescostata than the sex pheromone alone.     

甲基磺酸铝催化合成苯乙醛缩乙二醇

以结晶三氯化铝为原料制备了甲基磺酸铝,并以甲基磺酸铝为催化剂,环己烷为带水剂,用苯乙醛和乙二醇为原料合成了苯乙醛缩乙二醇,考察了影响产品收率的因素,优化了合成条件。该反应的较佳反应条件是:n(苯乙醛)∶n(乙二醇)为1∶2.0,甲基磺酸铝用量为2.0 g,环己烷10 mL(苯乙醛用量为0.1 mol时),回流2.0 h,苯乙醛缩乙二醇的收率达80.6%。实验结果表明,甲基磺酸铝对缩醛的合成反应具有较高的催化活性。     

MCM-41分子筛负载磷钨酸催化合成苯乙醛乙二醇缩醛

以MCM-41负载磷钨酸作催化剂,对以苯乙醛和乙二醇为原料合成苯乙醛乙二醇缩醛的反应条件进行了研究。文章较系统地研究了MCM-41负载磷钨酸催化剂、醛醇摩尔比、催化剂用最、反应时间诸因素对产率的影响。实验结果表明：最佳反应条件为：n（苯乙醛）：n（乙二醇）=1：1．2：0．0041,反应时间60min,带水剂环己烷11mL。上述条件下,苯乙醛乙二醇缩醛的产率可达86.5％。     

环氧苯乙烷催化异构为苯乙醛

对硝酸、盐酸和硫酸处理的活性炭的表面积和表面酸度进行了测定 ,并对该活性炭催化环氧苯乙烷异构为苯乙醛反应进行了研究 ,测定了该定向异构化反应的转化率、收率及其影响因素     

Odor of a papilionid butterfly

Benzaldehyde, phenylacetaldehyde (major component), 2-phenylpropenal,n-heptanal, 6-methylhept-5-en-2-one, and linalool were identified as compounds responsible for the male scent ofAtrophaneura alcinous alcinous. These substances were present predominantly in the wings, and the quantity of them was largest at the inner margin of the hind wing. Female wings also contained some of them in much smaller (except a few components) amounts. The relative proportion of each component exhibited manifests sexual differences.     

硅胶负载硫酸铈催化合成苯乙醛缩乙二醇

以苯乙醛和乙二醇为原料,以硅胶负载硫酸铈(Ce2(SO4)3/S iO2)为催化剂,合成了苯乙醛缩乙二醇,考察了醛醇摩尔比、反应时间、催化剂用量及其稳定性等因素对收率的影响。实验结果表明,较优反应条件为:苯乙醛0.1 mol,n(苯乙醛)∶n(乙二醇)=1.0∶1.5,催化剂用量0.2 g,带水剂环己烷12 mL,回流反应2.0 h,苯乙醛缩乙二醇的产率可达96.0%以上。     

溶剂对氧化苯乙烯液相重排制备苯乙醛反应的影响

以HZSM-5分子筛为催化剂,探讨了不同极性的溶剂对氧化苯乙烯液相催化重排制备苯乙醛反应的影响。结果表明,极性最强的DMF溶剂易吸附在分子筛表面,导致催化剂失活,使反应不能进行;极性稍弱的甲醇、乙醇和丙酮溶剂,加快了重排反应的速率,但易与苯乙醛反应生成副产物;弱极性和非极性溶剂性质稳定,能有效抑制催化剂积碳失活,其中1,2-二氯乙烷是氧化苯乙烯液相重排反应最适宜的溶剂。