Amination of biochar surface from watermelon peel for toxic chromium removal enhancement

Watermelon peel residues were used to produce a new biochar by dehydration method. The new biochar has undergone two methods of chemical modification and the effect of this chemical modification on its ability to adsorb Cr(VI) ions from aqueous solution has been investigated. Three biochars, Melon-B, Melon-BO-NH_2 and Melon-BO-TETA, were made from watermelon peel via dehydration with 50% sulfuric acid to give Melon-B followed by oxidation with ozone and amination using ammonium hydroxide to give Melon-BO-NH_2 or Triethylenetetramine(TETA) to give Melon-BO-TETA. The prepared biochars were characterized by BET, BJH,SEM, FT-IR, TGA, DSC and EDAX analyses. The highest removal percentage of Cr(VI) ions was 69% for Melon-B,98% for Melon-BO-NH_2 and 99% for Melon-BO-TETA biochars of 100 mg·L~(-1) Cr(VI) ions initial concentration and 1.0 g·L~(-1) adsorbents dose. The unmodified biochar(Melon-B) and modified biochars(Melon-BO-NH_2 and Melon-BO-TETA) had maximum adsorption capacities(Qm) of 72.46, 123.46, and 333.33 mg·g~(-1), respectively.The amination of biochar reduced the pore size of modified biochar, whereas the surface area was enhanced.The obtained data of isotherm models were tested using different error function equations. The Freundlich,Tempkin and Langmuir isotherm models were best fitted to the experimental data of Melon-B, Melon-BO-NH_2 and Melon-BO-TETA, respectively. The adsorption rate was primarily controlled by pseudo-second–order rate model. Conclusively, the functional groups interactions are important for adsorption mechanisms and expected to control the adsorption process. The adsorption for the Melon-B, Melon-BO-NH_2 and Melon-BO-TETA could be explained for acid–base interaction and hydrogen bonding interaction.     

In-chain functionalization by alternating anionic copolymerization of styrene and 1-(4-dimethylaminophenyl)-1-phenylethylene

Anionic copolymerizations of styrene (M₁) with excess 1-(4-dimethyl-aminophenyl)-1-phenylethylene (M₂) were conducted in benzene at 25°C for 24h, using sec-butyllithium as initiator. Narrow molecular weight distribution copolymers with M?;_n = 16.1 × 10³ g/mol (M?_w/M?_n = 1.04) and 38.2 × 10³g/mol (M?_w/M?_n = 1.05), and 24 and 38 moles of M₂ per macromolecule, respectively, were characterized by size exclusion chromatography, ¹H NMR spectroscopy and DSC. The monomer reactivity ratio, r₁ = 5.6, was obtained from the copolymer composition at complete consumption of M₁, assuming that the rate constant k₂₂ =0,i.e. r₂ =0. The polymers exhibited T_g values of 128 and 119°C, respectively, which correspond to an estimated T_g = 217°C for the hypothetical homopolymer of M₂.     

8种新型7胺-基取代的1,4二-氢-3H-2,3苯-并噁嗪-3甲-酸乙酯衍生物的合成

1,4二-氢-3H-2,3苯-并口恶嗪-3甲-酸乙酯经过硝化、还原和重氮化溴代得到了7溴--1,4二-氢-3H-2,3苯-并口恶嗪-3甲-酸乙酯(C)。以Pd(OAc)2/R(+)B INAP(2,2′-二苯膦-1,1′-联萘)为催化体系,C与苯胺、N-甲基苯胺、对氟苯胺、对乙氧基苯胺、环己胺、吗啡、四氢吡咯及六氢吡啶等8种有机胺类化合物(Am ine1~8),在氮气保护下,以碳酸铯为碱于干燥的甲苯中100℃反应16~24 h,生成了相应的8种新的7胺-基取代的1,4二-氢-3H-2,3苯-并口恶嗪-3甲-酸乙酯类化合物(D1~8),反应收率分别为83%、85%、71%、90%、72%、63%、75%和83%。通过1HNMR、质谱和元素分析对这些化合物的结构进行了表征。     

Characterization and performance of Pd-La/spinel catalyst for preparation of 2,6-diisopropylaniline

The Pd-La/spinel catalyst for the preparation of 2,6-diisopropylaniline (2,6-DIPA) by gas-phase amination of 2,6-diisopropylphenol (2,6-DIPP) has been studied. The catalysts before and after reaction were characterized by BET, XRD, differential thermal analysis (DTA)-thermo gravimetric analysis (TGA), FTIR, and NH₃-TPD techniques. The DTA study results show two kinds of coke deposited on the metal and support of Pd-La/spinel catalyst, and they are combusted at about 242 and 324 °C, respectively. The XRD and FTIR spectra of the Pd-La/spinel catalyst show that the coke contains the aromatic and aliphatic rings, alkyl groups, polynuclear aromatic system, hydroxyl groups, and amine groups. The reason for catalyst deactivation can be expressed as follows: coke formed on palladium metals may move from metal to the interface or boundaries of metal-support and acid sites of the support where further dehydrogenation and polymerization are occurring. The H₂ plays a key role in retarding coke formation, but must be in suitable amount to get relatively high selectivity. The rare earth promoter La not only promotes the activity and selectivity by retaining Pd species in the metallic state, but also decreases the formation of carbon by neutralizing the strong acid sites on the catalyst.     

Study of the amination of fatty alcohols catalyzed by Cu−Ni catalysts

Amination of fatty alcohols by hydrogenation and dehydrogenation catalysis is one of the main commercial processes for the production of dimethylalkylamines. The key factor in this process is the preparation of catalysts with high selectivity. A study of amination catalyzed by Cu−Ni catalysts supported on CaCO₃ is reported in this paper. Selectivity of the catalysts was adjustable by varying the ratio of Cu to Ni or by adding a third element (Zn or Mg). The promotion of catalyst selectivity was mainly attributable to the effect of the components on the reducibility of Ni²⁺ in the catalysts. Lower reducibility of Ni²⁻ led to higher catalyst selectivity.     

2，4－二硝基－6－氰苯胺的合成研究

以水杨酸为原料，经硝化、酰卤化、氨化等三步反应，得到重要的染料中间体２，４－二硝基－６－氰苯胺，总收率７０．５％。     

稀土元素对脂肪醇胺化催化剂性能的影响

无论是作为脂肪醇胺化催化剂的活性组分还是载体 ,La和Gd均能提高目前工业用Cu—Ni催化剂的活性和选择性 ,可以使生成的高沸物小于 2 % ,二甲基叔胺的收率大于 97% ,而Nd和Ce则无明显的促进作用。这些稀土元素均对催化剂的稳定性没有改善     

合成胺的工业化过程

回顾了最近十几年中甲胺、C2～C5的烷基胺、环已胺的合成工艺，重点讨论了技术的发展。研究过的新技术包括沸石催化的甲胺合成，异丁烯直接胺化制叔丁胺，以及催化精馏制丁胺和环已胺。还讨论了过程发展的方向。     

脂肪醇醚的催化胺化及其季铵化衍生物的制备

描述了用带气相循环的１０Ｌ反应系统进行醇醚（ＡＥＯ３）的催化胺制备醚叔胺的工艺以及醇醚叔胺的氯甲烷季铵化反应,制得两种醇醚叔胺及其季铵化衍生物,其中双烷基醚胺含量〉７０％,单烷基醚含量〉６５％,两种季铵盐活化物浓度为４０％,未反应胺〈１．３％。     

Palladium-catalysed amination of bromofluorans and an investigation of their thermochromic behaviour

The palladium-catalysed amination of readily accessible bromofluorans and bromobenzo[a]fluorans has been accomplished with a series of anilines and morpholine. The resulting aminofluorans generated intense black shades upon formulation in methyl stearate containing bisphenol A. The route provides an alternative approach to various amino substituted fluorans without the need of a series of individual diphenylamine intermediates.