山楂风味啤酒酿造工艺研究

目的 探究山楂风味啤酒酿造工艺的可行性。方法 以进口澳麦、小麦芽、啤酒花、山楂汁和山楂粉等为原料, 采用单醪浸出糖化法、经接种WB-06上面酵母、发酵等工艺制备山楂风味啤酒, 采用pH计检测成品啤酒的pH, 滴定法检测其总酸含量, 邻苯二胺法和碘量法分别检测其双乙酰和总黄酮含量, 并进行感官品评。结果 酿造出的山楂风味啤酒色度值在16~35 EBC, 总黄酮含量大于15 μg/mL, 双乙酰含量低于 0.15 mg/L, 总酸大于5 mL/100 mL。与传统小麦啤酒进行比较, 山楂风味啤酒不仅具有麦芽香和酒花香气, 还具有山楂果的香气, 口味清爽, 苦味适宜。结论 在小麦啤酒酿造工序中添加山楂制品酿造山楂啤酒是可行的, 可获得具有山楂风味, 且品质较好的啤酒。     

铝矾土粉料结构特性对铸型涂料性能的影响

通过涂料配比试验,分析了铝矾土粉料的体积密度、表面酸碱性及多孔结构对铸型涂料性能的影响。结果表明,采用高体积密度的铝矾土粉料可得到涂层致密的砂型醇基涂料;根据铝矾土粉料表面酸碱性合理选择聚合磷酸盐的种类,可使砂型水基涂料具有良好的稳定性;铝矾土粉料的多孔结构有利于改善消失模涂料的透气性。     

乙酸乙酯/乙酸丁酯联产工艺产品酸度控制模拟研究

根据乙酸乙酯与乙酸丁酯生产特点所提出的两者联合生产流程,采用模拟软件 AspenPlus 对联产工艺流程进行模拟计算,考察了回流比、侧线抽出位置、侧线抽出量、进料比变化对产品酸度的影响,得出了适宜的联产工艺操作条件,为试验研究提供理论指导。     

高温下多种工业固体废弃物复配体系的熔融特性研究

以粉煤灰、煤矸石、电石渣、镁渣和赤泥等五种工业固体废弃物为原料,按照不同酸度系数进行复配,分别采用灰熔融温度测定仪和高温黏度测定仪测定了高温下复配样品的熔融特征温度和黏度变化。结果发现,酸度系数在0.95~1.19范围内时,熔融特征温度随酸度系数的增大而升高;在酸度系数较大时,酸度系数对熔融温度的影响更为明显;熔体的黏度随温度降低而增加;当黏度在0~1000 mPa·s范围内,随样品中Fe2 O3含量增加,熔体黏度随温度的变化速度降低。     

Sulfated zirconia catalysts: Are Brønsted acid sites the source of the activity?

The thermal decomposition products of pyridinium sulfate differ from those of pyridinium sulfate supported on zirconia which in turn differs from that of pyridine adsorbed on a sulfated zirconia. Unsupported pyridinium sulfate decomposes to produce pyridine and sulfuric acid, and these subsequently react to produce oxides of carbon and sulfur. Zirconia that is sulfated and then exposed to pyridine does not release detectable amount of pyridine during heating in an inert gas; rather the pyridine undergoes oxidation reduction reactions simultaneously to release CO₂ and sulfur compounds. Pyridinium sulfate supported on zirconia decomposes upon heating to release pyridine and sulfuric acid, which reacts with the zirconia. The desorption of pyridine in one case and only CO₂/SO_x in the other case suggests that sulfated zirconia does not contain Brønsted acidity that can form pyridinium sulfate.     

甲苯-甲醇侧链烷基化制苯乙烯的研究进展

通过甲苯与甲醇在碱性催化剂作用下侧链烷基化制备重要化工原料苯乙烯,是具有重要工业价值和科学意义的一个反应。从催化剂体系、催化机理等方面综述了近年来国内外有关甲苯-甲醇侧链烷基化反应的研究现状,总结了目前催化剂研究中需要解决的问题,并对相应的改进方法提出了一些建议。     

Impact of curing condition on pH and alkalinity/acidity of structural wood adhesives

Nine formulations were selected for evaluating the effect of different curing methods on pH and alkalinity or acidity of various structural wood adhesives. These included four phenol–formaldehyde (PF) resins with high pH, one phenol–resorcinol–formaldehyde (PRF) resin with intermediate pH, two melamine–urea–formaldehyde (MUF) resins, and two melamine–formaldehyde (MF) resins with low pH. The four curing methods used in the study were: (1) curing at 102–105°C for 1 h (based on CSA O112.6‐1977), (2) four‐hour curing at 66°C followed by 1‐hour curing at 150°C (based on ASTM D1583‐01), (3) curing at room temperature overnight (based on ASTM D 1583‐01), and (4) cured adhesive squeezed out from glue lines of bonded shear block samples. The effect of the different methods on pH and alkalinity/acidity of the cured adhesive depended strongly on the individual adhesives. For the PF, the alkalinity was different for the different formulations in the liquid form, while in the cured form, the difference in the alkalinity depended on the curing method used. The MF and the MUF were the adhesives most affected by the method used. In particular, the MUF showed much higher cured film pH values when cured by method 2 compared to the other three methods, while both the cured MF and MUF exhibited quite variable acidity values when cured with the different methods. The PRF showed reasonably uniform cured film pH but varying acidity values when cured with the different methods. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Infrared characterization of the surface intermediates in the oxidation of toluene on vanadyl pyrophosphate catalysts

The adsorption and reaction of toluene on vanadyl pyrophosphate catalysts was studied by in situ infrared spectroscopy. Strongly adsorbed benzaldehyde and physically adsorbed cyclic anhydride species were observed at temperatures above 523 K. Water formed during reaction generates acid hydroxyl groups which cause a stronger adsorption of benzaldehyde and consecutive oxidation reactions. By co-adsorption of pyridine the acid sites are blocked and the deeper oxidation is suppressed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of slaked lime and gypsum on acidity alleviation and nutrient leaching in an acid soil from Southern China

A soil column experiment was made to study the effects of slaked lime (Ca(OH)₂) and gypsum (CaSO₄·2H₂O) on soil acidity, soil solution chemistry and nutrient leaching in an acid soil from Southern China. Results showed that application of sufficient slaked lime to initially increase the pH of the topsoil by 1 unit caused an increase in pH to 5 cm deeper than the layer of application as a result of bicarbonate leaching. With leaching of Ca from slaked lime or gypsum from the topsoil to the subsoil there was a decrease in exchangeable Al in the subsoil. Surface application of slaked lime or gypsum or both decreased the activity of toxic Al and increased AlSO₄⁺ activity in the subsoil solution. The Ca added in slaked lime or gypsum was accounted for by the increase in exchangeable Ca over the soil profile and the leaching loss. By contrast there was a negative balance of extractable sulfate and aluminum in the soil, indicating the formation of precipitates. There was little mineralisation of N and formation of NO₃^- under the conditions of the experiment. The leaching of cations in this soil treated with slaked lime or gypsum was driven by the dynamics of sulfate.