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51.
《Journal of Nuclear Science and Technology》2013,50(4):607-622
A calculation model has been developed in order to evaluate effectiveness of hydrazine and hydrogen co-injection (HHC) into reactor water for mitigation of intergranular stress corrosion cracking of structural materials used in boiling water reactors (BWRs). The HHC uses the strong reducing power of hydrazine radical, which is produced in the downcomer region under irradiation by γ-rays and neutrons. Some reactions and their reaction rate constants were determined based on experiments which were carried out in aerated water, hydrogenated water, and deaerated water. The calculated results were in good agreement with experimental data by a factor of two. The model was applied to a BWR and it was found that the HHC cut oxygen and hydrogen peroxide amounts dissolved in reactor water more effectively than hydrogen water chemistry alone. Thus, the required amount of hydrogen for hydrazine injection was much lower than that for hydrogen water chemistry. Consequently, electrochemical corrosion potential of structural materials could be lowered below–0:1V vs. SHE without any increase of MS line dose rate, which has been a limitation of the conventional hydrogen water chemistry. The HHC was predicted to decrease crack growth rate of structural materials by a factor of 10. 相似文献
52.
氧化钯使用常规的酸溶方法难溶。采用水合肼作为还原剂,于80 ℃时,在氧化钯的悬浮水溶液中,将氧化钯还原为金属钯黑,过滤后,该金属钯黑连同滤纸经过盐酸及硝硫混酸碳化处理后,钯进入溶液,从而解决了难溶氧化钯的溶样难题。然后,于pH 5.8的醋酸-醋酸钠缓冲介质中,以二甲酚橙为指示剂,锌盐返滴定过量EDTA,用丁二酮肟析出与钯等量的EDTA,三氯甲烷萃取丁二酮肟-钯沉淀,锌盐滴定析出的EDTA以测定钯含量,从而建立了水合肼还原-EDTA滴定法测定难溶氧化钯中钯的方法。按照实验方法测定实际样品中钯,结果的相对标准偏差(RSD,n=5)在0.12%~0.20%之间。对基准物质氧化钯中钯进行分析,测定值与理论值相符合。 相似文献
53.
《Journal of Sulfur Chemistry》2013,34(3):276-283
In this work, we have studied the reaction of substituted 2-thiocyanoacetophenone and hydrazine hydrate as a novel and simple pathway for the preparation of the substituted 1,4,5-thiodiazepine ring system. The mechanism of this reaction revealed that in the initial step condensation of hydrazine with carbonyl groups of substituted 2-thiocyanoacetophenons 2a–2f gives the corresponding substituted aromatic dithiocyano azide intermediates which in turn undergo cyclization to1,4,5-thiadiazepines in the presence of hydrazine. This cyclization is a novel method for the preparation of sulfide bond from the reaction of hydrazine and a dithiocyano intermediate. An account of the reaction mechanism is given. 相似文献
54.
Qiu YupingDai HaoDai HongbinWang Ping 《金属学报》2018,(9):1289-1296
Hydrous hydrazine (N2H4 center dot H2O) is a water-like liquid with a high hydrogen density (8%, mass fraction), relatively low cost, and satisfactory stability under ambient conditions. Owing to these favorable attributes, N2H4 center dot H2O has attracted considerable attention as a promising hydrogen carrier for on-board or portable applications. The synthesis of highly active and selective catalysts is a central issue in developing practical hydrous hydrazine-based hydrogen generation systems. The development of high-performance catalysts requires fundamental knowledge of the correlation between the surface composition of the catalyst and its catalytic performance. In the present work, a supported Ni-Pt/CeO2 bimetallic nanocatalyst was prepared by a one-pot co-reduction method, and its use for catalyzing hydrous hydrazine decomposition to generate hydrogen was reported. The surface composition of the Ni-Pt/CeO2 catalyst was regulated by heat treatments under different atmospheres, such as air, NH3, H-2, and CO and at different temperatures. It was found that changing the annealing conditions may result in altered Ni/Pt ratio at the catalyst surface, and as a consequence the catalytic performance can be tailored. When the molar Ni/Pt ratio at the catalyst surface was 0.8 similar to 1.14, the catalyst has been found to possess remarkable catalytic activity towards hydrous hydrazine decomposition. Additionally, it was found that incorporation of non-metallic N element on the catalyst surface may result in remarkably improved catalytic activity of NiPt/CeO2 towards hydrous hydrazine decomposition. This finding may open new avenues for the development of high-performance catalyst for promoting hydrogen generation from hydrous hydrazine. 相似文献
55.
介绍了水合肼产品及其应用领域,概述了水合肼的国内市场状况,分析了广西及周边地区水合肼的消费情况。市场分析结果表明水合肼作为一种液体产品,本公司虽有生产的原料优势,但市场销售优势并不明显,建设水合肼项目具有较大的市场风险。 相似文献
56.
以4-硝基苄醇为原料,分别采用Pd/C,Fe(Ⅲ)-MgO或Fe(Ⅲ)-水合肼为催化剂合成了对氨基苄醇。通过对比三种催化剂所得产物的收率和气相色谱检测的含量可知:以4-硝基苄醇合成对氨基苄醇时应选用Fe(Ⅲ)-水合肼为催化剂,其收率可达79.8%,气谱检测含量为98.7%。 相似文献
57.
研究了4-甲基-2-肼基苯并噻唑改进合成工艺.邻甲基苯基硫脲(简称苯基硫脲)溶于二氯乙烷中,然后通入氯气,生成4-甲基-2-氨基苯并噻唑盐酸盐(简称AMBT盐酸盐).然后以AMBT、AMBT盐酸盐和水合肼为原料,乙二醇为反应溶剂,通过取代反应合成4-甲基-2-肼基苯并噻唑.产品及重要中间体经红外光谱、核磁共振确定并经气相色谱测定产品纯度为98.2%,收率达到90.3%.综合考虑了影响反应的因素:成环反应试剂的选择、投料比、溶剂量、反应时间和反应温度.最佳反应条件:采用氯气来替代SOCl2或KBr,AMBT与水合肼的摩尔比为1∶6.5,乙二醇15 mL,取代反应时间为7 h,反应温度115℃.该路线工艺条件温合,操作简单,产品含量高,具有较好的社会效益和经济效益,适合工业化生产. 相似文献
58.
Jingqi Chi Lili Guo Jiayu Mao Tong Cui Jiawei Zhu Yanan Xia Jianping Lai Lei Wang 《Advanced functional materials》2023,33(46):2300625
The electrocatalytic production of hydrogen from seawater provides a low-cost way to realize energy conversion, but is restricted by high potential for seawater electrolysis and the chlorine oxidation reaction (ClOR) at the anode. Here, the self-growth of Mo-doped Ni2P nanosheet arrays with rich P vacancies on molybdenum-nickel foam (MNF) (Mo-Ni2Pv@MNF) is reported as bifunctional catalyst for Cl-free hydrogen production by coupling hydrogen evolution reaction (HER) with hydrazine oxidation reaction (HzOR) in seawater. Impressively, the Mo-Ni2Pv@MNF electrode as bifunctional catalyst has an excellent activity for overall hydrazine splitting (OHzS) with an ultralow voltage of only 571 mV at 1000 mA cm−2 and can maintain stability for an ultra-long time of 1000 h at 100 mA cm−2. Moreover, integration of OHzS into self-assembled hydrazine fuel cells (DHzFC) or solar cells can enable the self-powered H2 production. The industrial hydrazine sewage as feed for the above eletrolysis system can be degraded to ≈5 ppb rapidly. Density functional thoery calculations demonstrate that the electronic structure modulation induced by P vacancies and Mo doping can not only achieve thermoneutral ΔGH* for hydrogen evolution reaction but also enhance dehydrogenation kinetics from *N2H4 to *NHNH2 for HzOR, achieving enhanced dehydrogenation kinetics. 相似文献
59.
以水合肼和二硫化碳为原料合成了1,3-二氨基硫脲(简称TCH)。确定了合成中间体HDTC的最适宜工艺条件为水合肼:C_2=2.2:1(物质的量比)、温度 20℃、反应时间45min。重点对HDTC分解生成最终产物TCH的工艺进行了改进,结果表明:当HDTC分解反应在水合肼溶液中进行,并加入适量的仰制剂,不仅可使反应时间从20h缩短至8h,而且第一步反应结束后不必除去过量的水合肼即可进行第二步反应,TCH的产率接近90%。 相似文献
60.
Chemically beneficiated high silica/alumina iron ore rejects (27–76% Fe2O3) were used to synthesize iron oxides of purity 96–98% with SiO2/Al2O3 ratio reduced to 0.03. The major impurities on chemical beneficiations were Al, Si, and Mn in the range 2–3%. A 99.73% purity
Fe2O3 was also prepared by solvent extraction method using methyl isobutyl ketone (MIBK) from the acid extracts of the ore rejects.
The magnesium ferrite, MgFe2O4, prepared from these synthetic iron oxides showed high resistivity of ∼ 108 ohm cm. All ferrites showed saturation magnetization, 4πMs, in the narrow range of 900–1200 Gauss and the Curie temperature,T,
cof all these fell within a small limit of 670 ± 30 K. All ferrites had low dielectric constants (ε′), 12–15, and low dielectric
loss, tan δ, which decreased with the increase in frequency indicating a normal dielectric dispersion found in ferrites. The
presence of insignificant amount of polarizable Fe2+ ions can be attributed to their high resistances and low dielectric constants. Impurities inherent in the samples had no
marked influence on the electrical properties of the ferrites prepared from the iron ore rejects, suggesting the possibility
of formation of ferrite of constant composition, MgFe2O4, of low magnetic and dielectric losses at lower temperatures of 1000°C by ceramic technique. 相似文献