Seed-germination inhibition by volatile alcohols and other compounds associated withAmaranthus palmeri residues

Effects of 3-pentanone and eight low molecular weight aliphatic alcohols and aldehydes identifed in the mixtures of volatiles released byAmaranthus palmeri S. Wats. (AMAPA) residues were determined on germination of onion, carrot, AMAPA, and tomato seeds. Three-day exposures to these volatiles significantly inhibited germination of these assay seeds, and the inhibition was dependent upon exposure time and concentration. Based on the degree of inhibition observed in both time- and concentration-dependent assays, the following activity series was obtained: 2-heptanol > 3-methyl-1-butanol, 1-hexanol > hexanal, 1-pentanol, 3-pentanone, acetaldehyde > ethanol, 2-methyl-1-propanol. The activities of this group of compounds with that of 2-heptanone appear to be additive and related to test compound volatility and hydrophilicity. 2-Heptanol and 2-heptanone also significantly inhibited the germination of other species, including shepherdspurse, soybean, lettuce, alfalfa, common purslane, oats, and lovegrass.Name of companies or commercial products are given solely for the purpose of providing specific information; their mention does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned.     

石油羧酸盐/重烷基苯磺酸盐/碱复配体系的界面活性及吸附特性

实验考察了石油羧酸盐(POS-2和POS-4)/重烷基苯磺酸盐(ORS-41)/碱(NaOH)复配体系与大庆脱气原油(45℃粘度18.7 mPa·s)间的界面张力IFT(45℃)及2种表面活性剂在大庆去油油砂上的吸附特性.实验复配体系用矿化度4.3 g/L的模拟注入水配制.在复配体系中加入C2～C5正构脂肪醇使实验油水体系IFT达到平衡的时间由～70 min缩短至～50 min,使IFT稳定值(～5.8×10-3 mN/m)有所降低,各种醇的影响力相差不大,C3醇略好.当POS-2、ORS-41、C2、C3混合醇(1∶1)质量比为24∶8∶1时,在POS-2浓度0.6～6.0 g/L、NaOH浓度2.5～12 g/L范围出现超低IFT.POS-4/CTMAB或CPC/NaOH复配体系只在很窄的阳离子表面活性剂浓度范围出现超低IFT.OP类和Tween类非离子表面活性剂使POS-2/NaOH体系的IFT升高,升高幅度随加入量和乙氧基数增大而增大.POS-4和ORS-41在油砂上的吸附符合Langmuir定律,从POS-4/ORS-41/NaOH(2.5/0.83/12 g/L)复配体系中的吸附量(饱和吸附量为1.444和6.741 mg/g油砂),低于从POS-4/NaOH(2.5/12 g/L)和ORS-41/NaOH(0.83/12 g/L)体系中的相应吸附量(分别为2.925和7.581 mg/g油砂).图6表1参9.     

Methoxymethylation of Alcohols Catalyzed by Sulfated Metal Oxides

More acidic sulfated metal oxides (SMO) such as SO₄ ^2-/ZrO₂ and SO₄ ^2-/TiO₂ catalyzed the methoxymethylation of alcohols with dimethoxymethane at ambient temperature to achieve a product yield of greater than 90% within a few hours. The reaction displayed a significant steric effect on the product yield with a preferential order of primary alcohol > secondary alcohol tertiary alcohol. The observed steric effect might result from the repulsion between the bulky alkyl group in the alcohol and the two methoxy groups in the protonated dimethoxymethane (oxonium ion).     

Radioisotope tracer study of co-reactions of methanol with ethanol using 11C-labelled methanol over alumina, H-ZSM-5 and Cu-ZSM-5

¹¹C-labelled methanol was introduced for study of co-reaction of methanol with ethanol over alumina, H-ZSM-5 and Cu-ZSM-5 between 200 and 320 °C. The radio-method was applied to distinguish the radio-labelled methanol derivatives and co-products from unlabelled ethanol derivatives during analysis by radio-GC. The co-reaction was compared to ¹¹C-single methanol transformations from the previous work. Besides ¹¹C-dimethyl ether, ¹¹C-methyl ethyl ether as a co-product was formed between 200–240 °C and completely transformed further between 240 and 320 °C over H-ZSM-5 and alumina and partly over Cu-ZSM-5. In view of our results the appearance of ¹¹C-methyl ethyl ether intermediate is related to higher selectivities to form ¹¹C-traced C₃ and C₄–C₅ paraffins compared to the single ¹¹C-methanol transformation over H-ZSM-5 catalyst. These results suggest a modified methanol transformation pathway in the presence of ethanol over H-ZSM-5.     

影响啤酒中高级醇含量的主要因素及控制

阐述了影响啤酒高级醇含量的因素及控制高级醇形成的具体措施.     

Mixed alcohols synthesis from carbon monoxide hydrogenation over potassium promoted β-Mo2C catalysts

Potassium-promoted β-Mo₂C catalysts were prepared and their performances in CO hydrogenation were investigated. The main products over β-Mo₂C catalyst were C₁-C₄ hydrocarbons, only ∼4 C-atom% alcohols were obtained. The products of hydrocarbons and alcohols obeyed traditional linear Anderson-Schultz-Flory (A-S-F) distribution. However, modification with K₂CO₃ resulted in a remarkable selectivity shift from hydrocarbons to alcohols. Moreover, it was found that potassium promoter enhanced the ability of chain propagation of β-Mo₂C catalysts and resulted in a higher selectivity to C₂₊OH. For K/β-Mo₂C catalysts, the hydrocarbon products also obeyed traditional linear A-S-F plots, whereas alcohols gave a unique linear A-S-F distribution with remarkable deviation of methanol compared with that on β-Mo₂C catalyst. It could be concluded that potassium promoter might exert a prominent function on the whole chain propagation to produce alcohols. A surface phase on the K/β-Mo₂C catalysts such as the “K-Mo-C” explained the higher value for C₂₊OH, especially could promote the step of C₁OH to C₂OH, or could have a role in producing directly C₂OH, but again this would be speculative. At the same time, the influence of the loadings of K₂CO₃ on the performances of β-Mo₂C catalyst was investigated and the results revealed that the maximum yield of alcohol was obtained at K/Mo molar ratio of 0.2.     

The use of hydrated nickel–cobalt mixed oxide electrodes for oxidation of aliphatic and aromatic alcohols

Voltammetric studies and galvanostatic oxidation results for the electrochemical oxidation of octyl. hexyl, butyl, isobutyl and benzyl alcohols on hydrated nickel-cobalt oxide electrode in alkaline media are reported. These compounds are oxidised to their corresponding acids with high efficiency. The electrodes are not contaminated and hence their repeated use for the oxidation of same or different compounds is possible. Oxidation of benzyl chloride leads to formation of benzyl alcohol, benzaldehyde along with benzoic acid.     

EPOXIDATION OF FUNCTIONALIZED OLEFINS OVER SOLID CATALYSTS

Heterogeneous catalytic epoxidation of functionalized olefins in the liquid phase has been reviewed, focusing on catalyst performance and its interrelation with the crucial parameters of the catalytic systems. Efficient catalysts include supported and mixed oxides, framework-substituted (“redox”) molecular sieves, layered-type materials, heterogenized homogeneous catalysts, and some others. Among the various substrates, allylic and homoallylic alcohols, and unsaturated carbonyl compounds have received most attention so far. The great variety of available catalysts enables selective epoxidation of most substituted olefins. The mechanistic understanding of heterogeneous catalytic epoxidation is still underdeveloped, rendering catalyst design rather empirical. A considerable potential for future development lies in the area of “heterogenization” of successful homogeneous catalysts especially for asymmetric epoxidation. Crucial requirements in the development of heterogeneous catalytic epoxidation catalysts are, besides good catalytic performance and cheap oxidant, recyclability and resistance to leaching of the active component. Some of the examples shown in the literature do not fulfill the latter requirement.     

Narrow-range ethoxylation of fatty alcohols promoted by a zirconium alkoxide sulfate catalyst

Zirconium dodecanoxide sulfate is a very active catalyst in promoting fatty alcohol narrow-range ethoxylation. The catalytic activity is initially very high but rapidly decreases after the addition of one mole of ethylene oxide per mole of substrate. This peculiar behavior makes it possible to obtain narrow-range ethoxylated products containing not more than two or three ethylene oxide units. Because the catalyst shows a very feeble Brönsted acidity, it must be concluded that its activity originates from the Lewis acidity. This acidity is strongly enhanced from the introduction of the sulfate group in the catalyst molecule, because of the strong electron-withdrawing effect of this group. A kinetic model was developed for explaining experimental results.     

Interfacial activity of narrow-range alcohol oxyethylates

Surface and interfacial tension isotherms for narrow-range distribution ALFOL 1214 alcohol oxyethylates were determined and compared with those obtained for broad-range alcohol oxyethylates. Various adsorption parameters were estimated. The effectiveness of surface tension reduction decreases when the length of polyoxyethylene hydrophile increases. Micellization is observed at log cmc ranging from −4.7 to −3.3. Effects of the length and distribution of the polyoxyethylene chain on cmc are very small. A minimum of A _min/N _av ^0.5 is obtained for N _av=8, where A _min and N _av denote the minimum interfacial area occupied by a statistical molecule at the saturated interface and the average degree of oxyethylation, respectively. The interface becomes saturated at pC ₂₀=−5.61±0.35, where pC ₂₀ denotes the logarithm of concentration required to obtain the surface pressure equal to 20 mNm⁻¹. The highest and lowest values of the surface excess at saturation and the free energy of adsorption, respectively, are obtained for an average degree of oxyethylation equal to 8. Parameters are correlated with the average degree of oxyethylation and the oxyethylene chain distribution parameter according to empirical second-order polynomials. Small differences in adsorption abilities at the water/air interface are only observed for narrow- and broad-range distributed oxyethylates. The differences become important for adsorption at the hexadecane/water interface. The lowest values of interfacial tension are obtained for narrow-range oxyethylates with N _av=7 and 8. The Krefeld fabric detergency tests indicated that the best detergency was observed for alcohol oxyethylates with N _av=5–7. Narrow-range oxyethylates exhibit somewhat better washing abilities than the broad-range products. No relationship between detergency of alcohol oxyethylates and their abilities to adsorb at the water/air and water/hydrocarbon interfaces is observed.