Silphox [POCl3−n (SiO2) n ] as a new,efficient and heterogeneous reagent for the preparation of N-sulfonyl imines under solvent-free conditions

An efficient, simple and clean solvent-free procedure for the preparation of N-sulfonyl imines is described. The reaction of sulfonamides with different aromatic aldehydes in the presence of silica-phosphinoxide (Silphox) [POCl_3?n(SiO₂)_n] as a new and heterogeneous reagent affords the title compounds in good to high yields.     

Indoor air quality,air exchange rates,and radioactivity in new built temporary houses following the Great East Japan Earthquake in Minamisoma,Fukushima

This study measured air exchange rates, indoor concentrations of aldehydes and volatile organic compounds (VOCs), and radioactivity levels at 19 temporary houses in different temporary housing estate constructed in Minamisoma City following the Great East Japan Earthquake. The 19 surveyed houses represented all of the companies assigned to construct temporary houses in that Minamisoma City. Data were collected shortly after construction and before occupation, from August 2011 to January 2012. Mean air exchange rates in the temporary houses were 0.28/h, with no variation according to housing types and construction date. Mean indoor concentrations of formaldehyde, acetaldehyde, toluene, ethylbenzene, m/p‐xylene, o‐xylene, styrene, p‐dichlorobenzene, tetradecane, and total VOCs (TVOCs) were 29.2, 72.7, 14.6, 6.35, 3.05, 1.81, 7.29, 14.3, 8.32, and 901 μg/m³, respectively. The levels of acetaldehyde and TVOCs exceeded the indoor guideline (48 μg/m³) and interim target (400 μg/m³) in more than half of the 31 rooms tested. In addition to guideline chemicals, terpenes (α‐pinene and d‐limonene) and acetic esters (butyl acetate and ethyl acetate) were often detected in these houses. The indoor radiation levels measured by a Geiger–Müller tube (Mean: 0.22 μSv/h) were lower than those recorded outdoors (Mean: 0.42 μSv/h), although the shielding effect of the houses was less than for other types of buildings.     

Acetic acid removal by Saccharomyces cerevisiae during fermentation in oenological conditions. Metabolic consequences

The commercial Saccharomyces cerevisiae strains used in champagne winemaking were tested for their ability to metabolise acetic acid during alcoholic fermentation. Fermentation tests were performed in conditions close to oenological ones using a Chardonnay grape juice supplemented with acetic acid. The amount of acetic acid metabolised by wine yeast increased with increasing initial acetic acid concentration and this elimination occurred during the second part of the exponential growth phase. When the initial acetic acid concentration exceeds 1 g/l, and whatever the yeast strain used, the concentration of acetic acid in the resulting wine cannot be reduced to an acceptable level according to the current legislation. Acetic acid removal modified yeast metabolism, since more acetaldehyde, less glycerol and less succinic acid were produced. Considering the reduction of the NADPH/NADP⁺ ratio following acetic acid consumption, we propose, as a new hypothesis, that acetic acid could modify yeast metabolism by reducing the activity of the NADP⁺ dependent aldehyde dehydrogenase Ald6p.     

生物柴油醛、酮类污染物的排放特性与分析

采用2,4-二硝基苯肼(DNPH)衍生法和高效液相色谱(HPLC)技术,对柴油机排气中的醛、酮污染物进行了捕集和分离测定,考察了柴油机燃用BD100、BD50、BD0时,不同负荷下的醛、酮污染物排放规律,分析了燃料组分、缸内温度、压力、排气温度等对醛、酮污染物排放的影响。研究结果表明,该方法可实现微量醛、酮污染物的准确、快速测定;柴油机排气中含量较高的羰基物有甲醛、丙醛、丙烯醛、乙醛、丙酮、丁酮和丁醛,其排放水平均随负荷增大而呈下降的趋势;高负荷时,高温区域的滞留时间延长,醛、酮类被再次氧化、转化几率增加;较高的排气温度会促使排气中的醛、酮类物质和HC燃料再次氧化生成CO和CO2。     

柴油-生物柴油-乙醇混合燃料发动机的醛类化合物排放特性研究

在一台单缸柴油机上进行燃用BE-D与柴油后的醛类排放物试验对比,采用衍生法捕集发动机排气中的醛类污染物,应用液相色谱分析醛类成分与浓度。结果表明,排气中总醛类化合物的排放率随发动机负荷增加而减少;甲醛和乙醛是排放的醛类中占有率最大的两种醛,大部分工况下占有率达80%左右;C4以上的醛占有率很低。随发动机负荷增加,甲醛占有率增加,乙醛占有率减少;大多数工况下甲醛占有率比乙醛高。BE-D的总醛类化合物的排放率在1200r/min和1800r/min下较柴油低,1500r/min下较柴油高。BE-D的丙醛排放比柴油高,丙烯醛排放却比柴油低;丁醛排放在高负荷下BE-D比柴油高,低负荷下则比柴油低。提出了醛类化合物毒性当量的计算方法,并进行了计算,发现BE-D的醛类化合物毒性当量明显比柴油低,最低达40%。     

Effect of acetaldehyde and several acids on the formation of vitisin A in model wine anthocyanin and colour evolution

Summary It was found that the reaction between malvidin 3-glucoside and added pyruvic acid (PA), leading to the formation of vitisin A in model wine solutions, was not prevented by the addition of either acetaldehyde (A) or several organic acids. The acylated forms of vitisin A (3-acetylvitisin A and 3- p -coumarylvitisin A) were formed through the interaction of malvidin 3-acetylglucoside and malvidin 3- p -coumarylglucoside. Disappearance of the three main anthocyanins (malvidin 3-glucoside, malvidin 3-acetylglucoside and malvidin 3- p- coumarylglucoside) from the model wine with time followed first order kinetics. Acetaldehyde had the effect of increasing the total amount of these losses but producing smaller amounts of vitisin A. During ageing model solutions developed some browness. The brownest solution was obtained without A and a reduced rate of browning was found in the presence of A. This latter result can be explained by the assumption of a superimposition of a blueing effect upon reactions of A with anthocyanins. In the presence of PA the formation of vitisin A compounds gave an intermediate colour, contributing a reddish hue to the solution. A good correlation (r²= 0.96) between the percentage of vitisin A, of the total anthocyanins and the hue angle was observed. The addition of large amounts of organic acids that are normally found in wine into the model solutions did not lead to the formation of new anthocyanins. The linear loss of PA in all model systems indicates that a first order reaction occurs and 35.35 times more PA than total anthocyanin was lost to form the new compounds.     

The effects of selected aldehydes, ketones and carboxylic acids on off-flavours in water

The effects of selected aldehydes, ketones and carboxylic acids on the development of off‐flavours in water were studied. Combinations of hexanal, octanal, 2‐octanone, 5‐nonanone, hexanoic acid and nonanoic acid were rated by the off‐flavour intensities they created in water at concentrations just at or below the threshold value of each analyte. Two different sensory panels evaluated the off‐flavours induced by different combinations of the analytes. The observations of the two panels agreed well. From these studies, it could be concluded that aldehydes play an important role in the development of off‐flavours intensities in water. There were synergistic effects between aldehydes and ketones, as well as between aldehydes and carboxylic acids. Small amounts of aldehydes and carboxylic acids – well below their respective threshold values – caused an increase in the off‐flavour intensity. No synergism between ketones and carboxylic acids could be observed.     

双醛淀粉中有反应活性醛基含量的研究

将已知醛基含量的双醛淀粉水悬浮液在不同pH值条件进行各种加热处理.通过滴加羟胺,测定肟的生成数量,来计算有反应活性醛基((CHO)Toxime)的含量,有反应活性的醛基含量要比真实的醛基含量低.     

酚醛树脂复合板在热连轧机中的应用

重点分析了现有F7机架出口导卫装置的情况。原导卫材料是由铸钢制造 ,由于摩擦和高温常常引起热连轧带钢表面划伤 ,根据现场实际情况用酚醛树脂复合板替代铸钢导卫装置。实践表明 ,这种改造即可行又可靠 ,并取得了好的效果     

一种新型多功能建筑胶

该胶研制了一种由脲醛改性聚乙烯醇水性胶组成、具有成本低、性能好、用途广等特点，可广泛用于建筑及装饰行业的建筑胶。