葡萄糖与组氨酸热解产物分析及其在卷烟纸中的应用

模拟卷烟纸及卷烟纸助剂燃烧、热裂解环境和条件,采用PY-GC-MS联机分析方法和卷烟感官评吸方法,进行L-组氨酸、葡萄糖及L-组氨酸和葡萄糖混料的热解产物对比分析及应用评价,结果表明:①在200,500,700℃热解温度条件下,L-组氨酸和葡萄糖混料能够产生大量杂环类致香物质,热解反应产物种类数量明显多于L-组氨酸和葡萄糖热解产物种类之和;②L-组氨酸和葡萄糖混料热解反应温度低于L-组氨酸和葡萄糖,且在200℃时就能够发生较为复杂的热解反应;③L-组氨酸和葡萄糖混料能够有效地提高卷烟纸的抽吸品质,增加卷烟香气的丰富性。     

四种有机酸钾盐对卷烟纸热重及卷烟常规烟气的影响

采用同步热分析仪对添加四种有机酸钾盐的卷烟纸进行热重分析,同时检测卷烟常规烟气指标。结果表明,卷烟纸热失重起始温度及最大失重速率温度点与钾盐的含钾量有关,热失重起始温度点和最大失重速率温度点的高低均为:对照>葡萄糖酸钾>苹果酸钾>乙酸钾>草酸钾;焦油和一氧化碳释放量为:对照>葡萄糖酸钾>苹果酸钾>乙酸钾>草酸钾,对4种有机酸钾盐而言,较高的钾含量,卷烟纸起始失重温度和最大失重速率温度点相对较低,同时卷烟总粒相物、焦油和一氧化碳释放量也较低。     

五种卷烟纸助剂热裂解产物分析

对5种卷烟纸助剂在300,600,900℃的空气环境中进行热裂解,并对其裂解产物进行了对比分析。结果表明,5种卷烟纸助剂在不同温度条件下的主要裂解产物为醛酮、呋喃类、稠环芳烃类化合物。5种卷烟纸助剂的裂解产物种类也存在一定差异:柠檬酸镁、柠檬酸钙和柠檬酸锌在600℃和900℃条件下产生刺激性很大的丙烯醛物质;柠檬酸钙在热解过程中产生有刺激性的乙酸;柠檬酸镁、柠檬酸锌在热解过程中产生杂环类香味物质。     

低引燃倾向(LIP)卷烟纸热失重和热裂解产物的研究

采用热重分析法研究了低引燃倾向(LIP)卷烟纸的热失重行为。将LIP卷烟纸分别在300,600,900℃的空气环境下进行热裂解,并与对照卷烟纸的裂解产物进行对比。结果表明:①由于阻燃剂吸收部分热量,LIP卷烟纸起始裂解温度向低温方向偏移;②LIP卷烟纸的裂解产物和对照卷烟纸相比,物质和含量不同,但产物种类相同,主要是酮类、酯类、醛类、酸类物质,在LIP卷烟纸中还检测到21种致香成分,明显多于对照卷烟纸的7种,且致香成分的含量随裂解温度的升高而降低。     

卷烟纸用阔叶木浆热解行为研究

采用热分析以及热裂解气相色谱/质谱联用仪研究了卷烟纸用阔叶木浆的热解行为。在空气氛围中,将阔叶木浆分别在350、383、440和500℃下进行热裂解,并以GC/MS对其裂解产物进行定性和半定量分析。发现阔叶木浆可裂解出3-戊烯-2-酮、糠醛、2-甲基-苯酚和壬酸等47种产物。低温（350℃）下,裂解产物组分主要为醛类和呋喃类化合物,且随着裂解温度的增加,醛类和呋喃类的相对含量逐渐下降。酮类和酸类的相对含量随裂解温度的增加呈现先增大后减小的趋势,440℃达到最大值。在此温度下,阔叶木浆的热解产物对卷烟香气是最有利的。500℃时开始出现2-甲基萘等有害物质,酚类的种类和含量均增加。致香成分的减少和有害物质的增加主要是高温纤维素芳环化的结果。     

助燃剂对卷烟纸及卷烟烟气的影响研究

通过在卷烟纸上添加柠檬酸的钾、钠、镁和锌盐,采用透气度检测、同步热分析和卷烟烟气检测3种方法,研究卷烟纸助燃剂对卷烟纸和卷烟烟气的影响。结果表明:①4种柠檬酸盐在热态下能够提高卷烟纸的透气度,其中钾盐和钠盐提高的幅度较大;②在卷烟纸热解时,4种金属元素能够降低纤维素的热解活化能,其中钾和钠元素的催化作用较为明显;③在4种柠檬酸盐中,钾盐降焦和降CO的作用最为显著。     

活性炭催化热解纤维素协同制备酚类和合成气

苯酚和合成气均为工业生产中重要的基础化工原料。以自制的活性炭为催化剂,以纤维素为原料实现了催化热解液相产物中苯酚和气相产物中CO的同时富集。实验发现,生物质灰分中的钾、热解过程中催化剂/纤维素质量比和热解温度均对气液相产物的品质有着不同程度的影响。研究表明：钾的存在不利于热解产物品质的提高。钾虽然提高了生物油中苯酚的富集度,但降低了实际产率。而热解气中CO的浓度和产率均下降。对催化热解条件的研究表明热解温度450℃,催化剂比例为1∶1时可获得最佳的热解产物。此时,生物油中酚类物质占可检测有机物相对含量的62.31%,其中苯酚为45.37%,产率为1.78%（质量）。热解气中CO的浓度和产率分别为69.21%（体积）和 169.95 ml/g,热值为12.93 MJ/m³。     

卷烟纸用麻浆热解行为研究

采用热分析以及热裂解气相色谱/质谱联用仪研究了卷烟纸用麻浆的热解行为。在空气氛围中,将麻浆分别在350,400,466和500℃下进行热裂解,并以GC/MS对其裂解产物进行定性和半定量分析。结果发现,麻浆可裂解出3-戊烯-2-酮、糠醛、2-甲基-苯酚和庚酸等32种产物。低温(350℃)下,裂解产物组分主要为醛类和呋喃类化合物,且随着裂解温度的增加,醛类和呋喃类的相对含量逐渐下降。466℃时开始出现酚类,500℃时开始出现1-甲基萘等有害物质,酚类的种类和含量都增加了,但同样增加了酸类和醇类。致香成分的减少和有害物质的增加主要是高温纤维素芳环化的结果。     

蔗渣碱木素的热裂解特性

利用热重分析法研究了蔗渣碱木素的热解特性,并利用TG-FTIR和Py-GCMS对碱木素的热解产物种类及分布规律进行了分析。结果表明,木素热解呈现宽温度区域,可分为4个阶段,主要裂解温度范围为200～500℃,在400℃左右失重率最大,残余物得率较高。TG-FTIR分析显示了木素热解过程中气体产物的释放规律,300～500℃为主要热解挥发阶段,大部分气体产物在400℃左右产率达到最大。Py-GCMS分析表明,木素的热解产物大致可分为杂环、苯类芳香族、酚类芳香族、酯和酸等化合物,在主要热分解阶段,随着热解温度的升高,苯类和酚类芳香族化合物的含量增多,600℃时酚类物质的含量最高。     

基于PY-GC/MS的生物质组分间相互作用的热解实验

为研究生物质三组分间热裂解过程中的相互作用,利用热裂解-气相色谱/质谱联用仪（PY-GC/MS）联用的方法,对纤维素、木聚糖（半纤维素的模化物）和木质素进行单独热裂解及两两组分混合热裂解实验。单组分实验结果表明,在热解温度600℃、热解时间10s条件下纤维素的热解产物主要以左旋葡聚糖为主,木聚糖以乙酸和糠醛为主,而木质素主要以酚类物质为主。组分混合热裂解实验结果表明,纤维素促进了木聚糖热裂解生成更多的乙酸和糠醛,而木聚糖和木质素对纤维素热解生成左旋葡聚糖具有强烈的抑制作用;纤维素和木聚糖的存在大大促进了木质素热裂解生成酚类物质,而木质素抑制了木聚糖热裂解生成乙酸和糠醛。此外,研究还发现混合组分热解的相互作用受到热解温度和停留时间的影响。     

A study on the deposition of pyrolytic carbons from hydrocarbons

A new method for forming isotropic, laminar, and columnar pyrolytic carbons is proposed. For this, a low RPM (below 2.4 rpm) tumbling bed has been used to deposit pyrolytic carbons from hydrocarbon gases. All deposits were made on graphite substrates from propane and methane at a constant temperature of 1200°C. The microstructures of the pyrolytic carbons deposited were dependent on the flow pattern of the reactant gas, the rpm of the reactor, the hydrocarbon concentration, the nature of the hydrocarbon, and the geometry of the bed. Isotropic pyrolytic carbon is formed under deposition conditions where homogeneous nucleation occurs in the gas phase and at the gas flow conditions where the gas-borne droplets can collide on the substrate. Laminar carbon is formed under deposition conditions where homogeneous nucleation does not occur in the gas phase and at gas flow conditions where the carbon species existing in the bulk of the gas phase can collide on the substrate. Columnar carbon is formed when any carbon products existing in the bulk of the gas phase cannot collide on the substrate. The suggested deposition mechanism can also be applied to pyrolytic carbons deposited in a fluidized bed or in a stationary bed. In particular, isotropic carbon can be obtained even in a stationary bed if the requirements for the deposition of the isotropic carbon described above are satisfied.     

The influence of the waste ethylene vinyl acetate copolymer on the thermal degradation of the waste polypropylene

The pyrolysis of the waste polypropylene (PP), the waste ethylene vinyl acetate copolymer (EVA) and their blends has been carried out in a fixed bed reactor at 500 °C. The effect of different ratios of the waste EVA in the waste PP/EVA blends on the thermal degradation of the waste PP was investigated in terms of both product distributions and liquid fuel properties. The compositions of pyrolysis products were characterized in detail. The liquid products from the pyrolysis of the waste PP, the waste EVA and their blends were analyzed using different analytical techniques and fuel properties of pyrolytic liquids were investigated in comparison with commercial diesel. There were no synergistic effects between products from the waste PP and products from the waste EVA. While the ratio of the waste EVA increased in the waste PP/EVA blends, aromatic content of the pyrolytic liquids increased and subsequently paraffinic content of the pyrolytic liquids decreased. In addition, the boiling point distributions of pyrolytic liquids derived from the waste PP/EVA blends were found to be similar for all tested ratios of the waste PP/EVA blends.     

Antioxidant activity of amino acid sodium and potassium salts in vegetable oils at frying temperatures

Previous studies reported that several amino acids had strong antioxidant activity in vegetable oils under frying conditions. In this study, amino acids were converted to their sodium or potassium salts, and a heating study was conducted with 5.5 mM amino acid salts in soybean oil (SBO) at 180°C. Sodium salts of amino acids including alanine, phenylalanine, and proline and disodium glutamate had significantly stronger antioxidant activity than the corresponding amino acids, and potassium salts had stronger antioxidant activity than sodium salts. Potassium salts of alanine and phenylalanine more effectively retained tocopherols in SBO than the corresponding amino acids during heating. Phenylalanine potassium salt had stronger antioxidant activity than phenylalanine in other vegetable oils including olive, high oleic soybean, canola, avocado, and corn oils. Phenylalanine potassium salt at 5.5 mM more effectively prevented oil oxidation than tert-butyl hydroquinone, a synthetic antioxidant, at its legal concentration limit (0.02%) indicating its feasibility as a new antioxidant for frying.     

Evaluation of two different scrap tires as hydrocarbon source by pyrolysis

The main objective of the present study is to investigate the effect of the polymer types in scrap tires on the pyrolysis products. Two different types of scrap tires (passenger car tire, PCT and truck tire, TT) have been pyrolyzed in a fixed bed reactor at the temperatures of 550, 650 and 800 °C under N₂ atmosphere. Pyrolysis products (gas, oil and carbon black) obtained from PCT and TT were investigated comparatively. The gaseous products were analyzed by GC–TCD. The psychical and chemical properties of pyrolytic oils were characterized by means of GC–FID, GC–MS, ¹H NMR. In addition, boiling point distributions of hydrocarbons in pyrolytic oils were determined by using simulated distillation curves in comparison with commercial diesel fuel. The production of activated carbon from pyrolytic carbon blacks (CBp) was also carried out. The composition of gaseous products from pyrolysis of PCT and TT were similar and they contained mainly hydrocarbons (C₁–C₄). Pyrolytic oils were found lighter than diesel but heavier than naphtha. The physical properties of pyrolytic oils from PCT and TT were similar at the same temperature. However, the composition of aromatic and sulphur content from pyrolysis of PCT was higher than that of TT. Furthermore, TT derived pyrolytic carbon black was found more suitable for the production of activated carbon due to its low ash content.     

Synthesis and pyrolysis of Ti‐containing precursors for advanced Si/C/N/Ti‐based ceramics

A new kind of polytitanosilazane (PTSZ) precursor for Si/C/N/Ti‐based ceramic was synthesized from the condensation reaction of silazane lithium salts and titanium tetrachloride (TiCl₄). Titanium in the precursors was bonded to silazane compounds in the Si—N—Ti bond. The obtained PTSZs were characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and elemental analyses. The PTSZs were pyrolyzed at 900 to 1300°C under nitrogen, argon, and ammonia atmosphere, respectively, to give amorphous inorganic products. The results indicated that ceramic yields of PTSZs were much higher than that of their corresponding silazane oligomers and ceramic yields increased with the increase in Ti content in PTSZs. Precursors containing reactive vinyl groups gave higher pyrolytic yields. The pyrolytic yield under ammonia is lower than that under nitrogen and argon. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2733–2739, 2004     

Foliar spraying of potassium gluconate promotes the synthesis of the seed oil of Styrax tonkinensis

Styrax tonkinensis is a promising woody biodiesel species. In this experiment, we investigated how foliar spraying of potassium gluconate solution affected the production of seed oil in S. tonkinensis. Leaf spraying of potassium gluconate solution appreciably promoted the photosynthesis of S. tonkinensis leaves through both the light reaction and the dark reaction. By boosting the activity of enzymes involved in glucose metabolism and seed oil synthesis, foliar spraying of potassium gluconate solution also dramatically enhanced glucose metabolism and seed oil synthesis in the S. tonkinensis seeds. This indicates that foliar spraying with potassium gluconate solution discernibly improved the synthesis of seed oil in S. tonkinensis by encouraging the transit of photosynthetic products from the source to the reservoir and the flow of carbon into the seed oil synthesis in the seeds. Overall, the medium concentration of potassium gluconate solution (4 g/L) was found to be the most effective for increasing the oil content of S. tonkinensis seeds. While higher potassium gluconate solution concentrations (6 g/L) had a slight inhibitory effect on specific indicators (ACCase) during specific seed development periods. This study highlighted the importance of potassium for seed oil synthesis in woody plants and provided a useful foundation for future cultivation practices aimed at enhancing seed oil synthesis in woody plants.     

Applications of Phase Transfer Catalysis to Arenediazonium Cation Chemistry

Arenediazonium cations have been known for many years but the synthetic utility has been diminished by their lack of stability and by their proclivity for undergoing sundry side reactions. Arenediazonium BF₄ and PF₆ salts are generally stable solids, but are relatively insoluble in nonpolar organic media. Crown complexation and other forms of phase transfer catalysis increase solubility and allow numerous synthetic transformations to be conducted in good yield. The yield improvements result from a reduction in competing side reactions rather than any fundamental change in mechanism. The reactions to which the phase transfer technique is successfully applied are diazo coupling, reduction, halogenation, arylation and cyclization. In the latter case, the use of potassium superoxide is sometimes a more efficacious reagent than potassium acetate. The phase transfer approach can be used in the high yield synthesis of arenediazosulfones and arenediazocyanides. The latter undergo cycloaddition with many dienes to yield pyridazine derivatives.     

Continuous thermal degradation of pyrolytic oil in a bench scale CSTR reaction system

Continuous thermal degradation of two pyrolytic oils with low (LPO) and high boiling point distribution (HPO) was conducted in a constant stirrer tank reactor (CSTR) with bench scale. Raw pyrolytic oil as a reactant was obtained from the commercial rotary kiln pyrolysis plant for municipal plastic waste. The degradation experiment was conducted by temperature programming with 10 °C/min of heating rate up to 450 °C and then maintained with long lapse time at 450 °C. Liquid product was sampled at initial reaction time with different degradation temperatures up to 450 °C and then constant interval lapse time at 450 °C. The product characteristics over two pyrolytic oils were compared by using a continuous reaction system. As a reactant, heavy pyrolytic oil (HPO) showed higher boiling point distribution than that of diesel and also light pyrolytic oil (LPO) was mainly consisting of a mixture of gasoline and kerosene range components. In the continuous reaction, LPO showed higher yield of liquid product and lower residue than those of HPO. The characteristics of liquid products were influenced by the type of raw pyrolytic oil. Also, the result obtained under degradation temperature programming was described.     

高铁酸钾的制备方法及应用

对次氯酸盐氧化法制备高铁酸钾的工艺进行了研究,确定了NaClO、铁盐、配比、反应温度和时间等工艺条件,并对高铁酸钾的性能与其他药剂进行了处理效果的比较,说明了高铁酸钾是一种多功能的水处理药剂.