7428-48-0Relevant articles and documents
Preparation of PbS and PbSe nanocrystals by a new solvothermal route
Gautam, Ujjal K.,Seshadri, Ram
, p. 669 - 676 (2004)
A new solvothermal route for the preparation of nanocrystals of PbS and PbSe, involving the reaction of lead stearate with sulfur or selenium and tetralin (tetrahydronaphthalene) in toluene solvent is described. Tetralin in the presence of S/Se gives H2S/H2Se and gets aromatized to naphthalene. The nanocrystals have been characterized by powder X-ray diffraction and electron microscopy. Use of surfactant Triton X-100 (polyoxyethylene(10)isooctylphenyl ether) resulted in both nanorods and nanoparticles of PbSe. Capping by citric acid and malonic acid reduce the particle sizes to less than 10nm.
Scanning Tunneling Microscopy and UV-Visible Spectroscopy Studies of Lead Sulfide Ultrafine Particles Synthesized in Langmuir-Blodgett Films
Zhu, Rong,Min, Guangwei,Wei, Yu,Schmitt, Hans J.
, p. 8210 - 8211 (1992)
Ultrafine semiconductor particles of lead sulfide were synthesized by exposing lead stearate Langmuir-Blodgett films to hydrogen sulfide gas.By heating the Langmuir-Blodgett films containing PbS ultrafine particles in nitrogen gas at 120 deg C for 1 h, the molecules for stearic acid were evaporated and the lead sulfide particles were left.The PbS ultrafine particles before and after evaporation were analyzed by using a scanning tunneling microscope and a UV-visible spectrophotometer.
Coordination geometry of lead carboxylates - Spectroscopic and crystallographic evidence
Catalano, Jaclyn,Murphy, Anna,Yao, Yao,Yap, Glenn P. A.,Zumbulyadis, Nicholas,Centeno, Silvia A.,Dybowski, Cecil
, p. 2340 - 2347 (2015/01/30)
Despite their versatility, only a few single-crystal X-ray structures of lead carboxylates exist, due to difficulties with solubility. In particular, the structures of long-chain metal carboxylates have not been reported. The lone electron pair in Pb(ii) can be stereochemically active or inactive, leading to two types of coordination geometries commonly referred to as hemidirected and holodirected structures, respectively. We report 13C and 207Pb solid-state NMR and infrared spectra for a series of lead carboxylates, ranging from lead hexanoate (C6) to lead hexadecanoate (C18). The lead carboxylates based on consistent NMR parameters can be divided in two groups, shorter-chain (C6, C7, and C8) and longer-chain (C9, C10, C11, C12, C14, C16, and C18) carboxylates. This dichotomy suggests two modes of packing in these solids, one for the short-chain lead carboxylates and one for long-chain lead carboxylates. The consistency of the 13C and 207Pb NMR parameters, as well as the IR data, in each group suggests that each motif represents a structure characteristic of each subgroup. We also report the single-crystal X-ray diffraction structure of lead nonanoate (C9), the first single-crystal structure to have been reported for the longer-chain subgroup. Taken together the evidence suggests that the coordination geometry of C6-C8 lead carboxylates is hemidirected, and that of C9-C14, C16 and C18 lead carboxylates is holodirected.
Synthesis of biodiesel via homogeneous Lewis acid catalyst
Di Serio,Tesser,Dimiccoli,Cammarota,Nastasi,Santacesaria
, p. 111 - 115 (2008/10/09)
Nowadays, most biodiesel (fatty acids methyl esters, FAME) is produced by the transesterification of triglycerides (TG) of refined/edible type oils using methanol and an homogeneous alkaline catalyst. However, production costs are still rather high compared with the ones of petroleum-based diesel fuel. To lower costs and make biodiesel competitive less-expensive feedstocks such as waste fats or non-edible type oils could be used. The use of homogeneous alkaline catalysts in the transesterification of such types of fats and oils poses great difficulties due to the presence of large amounts of free fatty acids (FFA). This paper studies the use of carboxylic salts as a possible alternative, because these catalysts are active also in the presence of high FFA concentrations. The most active catalyst (Cd, Mn, Pb, Zn carboxylic salts) have been individuated and a correlation of the activities with the cation acidity has been found.
