火试金法测定多金属复杂铜阳极泥中金

铜阳极泥中因含有大量金、银、铂、钯等贵金属而具有较高回收价值,其中金是价值最高的元素,金的精准检测对其综合回收具有重要指导意义。由于生产铜阳极泥的阳极板成分、生产指标控制、设备设施水平等因素的不同,导致其主要成分及含量均有较大差异,实验针对代表性的多金属复杂铜阳极泥,考察了多因素对火试金检测结果的影响。在硅酸度K=1.8、铅扣质量为35 g、氧化铅过量系数为1.8、熔炼温度为1100℃、熔炼升温时间和保温时间均为30 min时,加标回收率在99.4%~101%,RSD为0.15%~0.29%。优化条件下可实现多金属复杂铜阳极泥中金的精准检测。     

火试金减杂-电感耦合等离子体原子发射光谱法（ICP-AES）法测定高冰镍的金、银、铂、钯含量

建立了火试金减杂-电感耦合等离子体原子发射光谱法（ICP-AES）测定高冰镍中金、银、铂、钯含量的分析方法。实验采用火试金富集、熔融、灰吹得到合粒,通过减杂法得到银含量,通过ICP-AES法测定得到金、铂、钯含量。金、银、铂、钯的加标回收率在99.53%-101.83%之间,相对标准偏差小于3%。此方法快速、简洁,准确度高、精密度好,能够满足高冰镍的测定需求。     

火焰原子吸收光谱法直接测定锡阳极泥中的银

建立了火焰原子吸收光谱法(FAAS)测定锡阳极泥中银含量的方法。文章考察了不同的测定介质、酸度对测定结果的影响。实验结果表明在选定条件下,锡阳极泥中的锡、锑、铅等杂质不干扰银的测定。方法加标回收率在99.2%~103%,精密度实验结果表明,相对标准偏差(RSD,n=11)均小于4%。操作过程简单,能满足生产的需要。     

火试金-重量法测定阳极铜中的金和银

阳极铜是铜电解过程的重要产品,其中含有一定量的金、银等贵金属,快速准确地测定阳极铜中的贵金属含量,具有重要的现实意义。采用火试金重量法可以同时且快速地测定出样品中的金量和银量,试样与适量的熔剂经高温熔融,铅将金、银富集起来形成铅扣,灰吹得到金、银合粒,用硝酸分金,重量法测得金量;用电感耦合等离子体发射光谱(ICP-OES)法测定分金液中的杂质量和金量,合粒质量减去金量及杂质量即为银量。此方法精密度好,准确度高。金、银的加标回收率在97.6%~102%,可以很好地满足阳极铜中金、银含量的测定。     

乙酸除铋火试金法测定粗铋中的金银含量

建立了用乙酸分离粗铋中铋-火试金重量法测定粗铋中金和银含量的方法。首先把粗铋焙烧氧化,然后用乙酸溶解粗铋的氧化物,过滤除去铋,消除铋对火试金法的干扰,将沉淀物灰化后,配料、高温熔融,熔态的金属铅捕集试样中的贵金属形成铅扣,将铅扣灰吹,得到金银合粒,用硝酸溶解分离金,用重量法测定金含量。方法准确度高,精密度好,金的加标回收率为99.2%～101%,银的加标回收率为98.2%～99.7%。能很好地满足粗铋中金、银的测定。     

碘酸钾滴定法测定铜阳极泥分银渣中的锡

建立了碘酸钾滴定法测定铜阳极泥分银渣中锡的含量。通过硝酸溶解,过滤除铜,还原铁粉置换分离锑、铋、砷等元素,消除了铜阳极泥分银渣中的铜、锑、砷等杂质元素对锡测定的干扰。方法加标回收率在99.7%~100%。精密度实验结果表明,相对标准偏差(RSD,n=11)小于1.1%。操作过程简单,能满足生产的需要。     

火试金富集-ICP-AES法测定锡阳极泥中的铂、钯

确立了火试金富集-电感耦合等离子体原子发射光谱法(ICP-AES)测定锡阳极泥中铂、钯的分析方法。在实验确定的分析谱线及最佳工作条件下,方法测定铂,钯的加标回收率在95%~98%,相对标准偏差(n=8)均小于3%。方法简便、快速,能够满足日常分析对锡阳极泥中铂、钯的测定要求。     

火试金法测定锡阳极中金量和银量

锡阳极是锡冶炼过程中的一种中间产物,其中含有大量的金银贵金属。准确测定锡中金银含量有很重要的现实意义。采用火试金法能实现锡中金、银连测,该方法准确度高,精密度好,金银回收率在97.47～101.66％之间,能很好的满足锡阳极中高品位金银的测定。     

焙烧除硒-火试金法测定银硒渣中金、银含量

建立了银硒渣中金、银含量的测定方法。通过高温焙烧除去银硒渣中的硒,然后用火试金法测定金、银含量。硒在750℃下焙烧30min能够完全除去,不会对火试金中金、银造成损失,在焙烧时铺垫二氧化硅避免样品黏附在试金坩埚壁上,并且配料时易于搅拌均匀。通过加标回收实验,测得金回收率为98.9%～101%,银的回收率为96.3%～98.6%。金相对标准偏差(RSD)小于2.5%,银相对标准偏差(RSD)小于1.1%。方法不仅简单、快速,而且准确度高、精密度好。     

混砂焙烧-火试金法测定文丘里泥中金、银含量

建立了文丘里泥中金、银含量的测定方法。将所称试样置于已有10g的石英砂中,并混匀;在750℃的条件下焙烧90min除去硒后,将冷却至室温的试料搅散,加入试金熔剂,用火试金法连续测定金、银的量。测定文丘里泥中金、银的相对标准偏差分别小于1.5%、0.70%,加标回收率金为98.6%～103%;银为96.7%～98.2%。结果稳定、可靠,且同时测定金、银含量。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.