PERFORMANCE OF A MULTISTAGE FERMENTOR WITH CELL RECYCLE FOR CONTINUOUS ETHANOL PRODUCTION

The unsteady and steady-state performance of a multistage fermentor with cell recycle is investigated numerically for continuous production of ethanol. The tanks-in-series model is employed to describe the flow behaviour of culture in multiple tanks. In establishing mass balances, the cell volume fraction and the equilibrium partition coefficient for intracellular and extracellular ethanol concentrations are taken into account. Kinetic expressions are taken from the literature. Compared to a single tank fermentor with recycle, multi-staging and cell recycle are shown to bring high cell and product concentrations and low substrate concentration in the final tank during unsteady-state operation. Solutions to the steady state model are presented graphically, showing concentrations as a function of dilution rate for different numbers of tanks. Results are given for the maximum ethanol productivity as a function of the optimal dilution rate, with parameters of tank number, bleed ratio and recycle ratio. Also, the effects of the fractional tank volume and the saturation constant on the productivity and the substrate conversion are examined.     

Synthesis of derivatives of alkylamino alkyloxy propanol structures by N-alkylation, acylation, and nitration. Application as fuel additives

Polyfunctional compounds were prepared by alkylation, acylation, and nitration of hydroxyl and amine functions of the following alkanolamine ether structures: (di)alkylamino alkyloxy propanol, hydroxy alkyloxy (di)alkylamino propanol, and their dimer compounds. The resulting compounds were characterized by conventional spectroscopic methods, and complete nuclear magnetic resonance data are given. These reactions extented the application of these propanic compounds to use as multipurpose fuel additives. In particular, they enhance phase stability and improve the cetane number in ethanol-diesel fuel blends.     

Chemical celluloses derived from Pinus radiata wood pulps for nitrocellulose preparation

The nitration capabilities of a range of chemical celluloses, including some containing the cellulose-II polymorph, were examined. The cellulose samples, derived from Pinus radiata wood by bisulphite, prehydrolysis-kraft or kraft pulping, were compared with a commercial nitration-grade cellulose and two bleached cotton linters samples. All samples on nitration gave nitrocelluloses (degree of substitution ≈ 2–45) which had satisfactory stabilities and solubilities, with the exception of a P. radiata bisulphite cellulose which had a high pentosan value. The presence of cellulose-II in the samples was not an impediment to the nitration. High performance size exclusion chromatography of the nitrocelluloses showed that the molecular weight distributions of samples derived from the P. radiata celluloses were generally similar to that derived from a commercial nitration-grade cellulose.     

一种合成间硝基苯甲醛的新方法

报道一种合成间硝基苯甲醛的新方法，将苯甲醛先制成苯甲醛缩亚胺，再硝化制得间硝基苯甲醛，该法具有异构体少、分离简便、收率高、产品纯度好的特点，较苯甲醛硝化法经济效益显著。     

3-硝基-1,8-萘酐的合成

研究了乙酸和乙酸酐反应体系下,利用硝酸盐对1,8-萘酐进行的硝化反应,发现在该体系当中,多数硝酸盐可以将1,8-萘酐进行硝化,最终在其3-位引入1个硝基。     

ATMOSPHERIC OCCURRENCE OF 2-NITROBENZANTHRONE ASSOCIATED WITH AIRBORNE PARTICLES IN CENTRAL TOKYO

2- and 3-Nitrobenzanthrones (NBAs) in airborne particles collected in central Tokyo on a seasonal basis from 1996 to 2001 are quantified and possible sources are investigated. The concentrations of 2- and 3-NBA are found to range from 49 to 831 fmol m^–3and 0.5 to 3.5 fmol m^–3, while the nitrated polycyclic hydrocarbons 1-nitropyrene and 2-nitrofluoranthene are found at concentrations of 100–492 fmol m^–3 and 10–97 fmol m^–3. Significant linear correlations are identified between 2-NBA and NO₂, a photochemical product, suggesting that 2-NBA is formed by atmospheric reactions of benzanthrone initiated by hydroxyl or nitrate radicals in the presence of NO₂. 2-NBA is not correlated with directly emitted compounds such as 1-nitropyrene. The concentration ratio of 2-NBA to 1-nitropyrene is 5 or greater in all samples. Nitrated polycyclic aromatic compounds formed by atmospheric reactions therefore appear to represent a substantial contribution to the mutagenicity of airborne particulate matter.     

Chlorination,Nitration, and Amination Reactions of Asphaltene

Asphaltenes are well known for their problematic characterstics during petroleum refining as well as dubiously complex structure. In this work, chlorination of various types of asphaltenes have been achieved by sulfuryl chloride with and without AIBN initiator, while nitraion and reactions with amines (aniline, triethylamine, t-butyl amine, and piperidine) were accomplished through nitrous acid and diazotization process, respectively. The charaterization of the products obtained were performed by FTIR spectroscopy. The data regarding the composition of the asphaltenes generated in this work will surely enhance our understanding toward the asphaltenes. It is envisaged that such reactions will provide an opportunity to investigate further the reacting behavior of asphaltenes for better industrial use.     

5-硝基-3-三硝甲基-1H-1,2,4-三唑和5,5'-双(三硝甲基)-3,3'-偶氮-1H-1,2,4-三唑的合成与理论研究

以氨基胍碳酸氢盐与丙二酸为原料,经缩合-环化反应、重氮化-取代反应、氧化偶联反应和硝化反应分别合成出5-硝基-3-三硝甲基-1H-1,2,4-三唑(TNNT)和5,5'-双(三硝甲基)-3,3'-偶氮-1H-1,2,4-三唑(BTNAT)。用红外光谱、核磁共振、元素分析表征了它们的结构。进行了B3LYP/6-31G(d,p)基组水平下它们的全结构优化和自然键轨道(NBO)分析。用DSC测定了它们的分解温度。结果表明,10℃·min~(-1)升温速率,氮气气氛条件下,TNNT和BTNAT的分解温度分别为135℃和146℃。     

2,6-二硝基-3,7-二硝亚胺基-2,4,6,8-四氮杂双环[3.3.0]辛烷的合成及性能

以二硝基甘胍为原料,乙酸酐为酰化试剂,经酰化及硝化反应得到一种新型高能量密度化合物2,6-二硝基-3,7-二硝亚胺基-2,4,6,8-四氮杂双环[3.3.0]辛烷(四硝基甘胍,TNGG),并对其结构进行了表征。研究了影响TNGG产率的因素,并通过热重分析-差示扫描量热分析(TG-DSC)研究了其热分解行为,基于密度并结合等键反应及Kamlet-Jacobs公式计算得到该化合物的爆轰性能。结果表明,在反应时间为15 min,温度为25℃,98%发烟硝酸/P_2O_5硝化体系下,TNGG的产率最高,为31.3%。该化合物热分解过程在700℃内完成,整个过程失重约为100%,热分解峰温为182.6℃,热稳定性较好。理论计算结果表明,TNGG水解稳定性优于四硝基甘脲(TNGU)。TNGG的理论爆速为9.76 km·s~(-1),爆压为44.0 GPa,优于RDX和HMX。     

二硝基甲苯硝化反应的热危险性分析

采用差示扫描量热仪(DSC)、绝热加速度量热仪(ARC)和反应量热仪(RC)对二硝基甲苯(DNT)硝化反应的热危险性进行了研究。DSC的测试结果表明产物梯恩梯(TNT)的起始分解温度是298.38℃,低于DNT的起始分解温度;而ARC的测试结果显示TNT的开始分解温度为232℃,最大反应速率达到时间为24h时所对应开始温度TD24为224℃;反应量热实验表明DNT硝化过程的放热剧烈,且110℃时反应放热量是90℃的1.4倍,这些热量中有很大一部分来自于副反应放热。因此,该反应必须严格控制温度,避免温度过高引起放热副反应加剧和产物的二次分解。