4402-30-6Relevant articles and documents
Structural and Thermodynamic Study of the Effect of Sterically Hindering Alkyl Groups on Complex Stability
Damu, Kirty V.,Maumela, Hulisani,Hancock, Robert D.,Boeyens, Jan C. A.,Dobson, Susan M.
, p. 2717 - 2722 (1991)
The balance between steric and inductive effects on the thermodynamic stability of complexes in aqueous solution has been examined as the bulk of N-alkyl substituents is increased along the series methyl, ethyl, isopropyl, tert-butyl.The ligands 7,16-diisopropyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (L3), and RN2 (R = Me, L4; Pri, L5; or But, L6) have been prepared.The formation constants of these ligands, and of other ligands with bulky N-alkyl groups, have been determined with the metal ions CuII, ZnII, CdII, PbII and with CaII, SrII and BaII (L3 only).The N-isopropyl groups of of ligand L3 cause a sharp drop in thermodynamic complex stability for all metal ions, whereas in the series L2-L4 lead(II) is unusual in showing a strong increase in complex stability in response to the inductive effects of the larger alkyl groups.In an attempt to understand the lowering of complex stability by the N-isopropyl groups of L3 the crystal structure of the complex 3>I was determined: monoclinic, space group P21/c, a = 12.603(2), b = 14.875(3), c = 13.877(3) Angstroem, β = 112.81(1) deg, Z = 4, final R = 0.042.The structure indicates some stretching of the K-N bond by the presence of the N-isopropyl groups.The parallel between steric hindrance effects by bulky N-alkyl groups and hard and soft acid and base behaviour is discussed.
METHOD FOR PRODUCING CIS- AND TRANS-ENRICHED MDACH
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, (2017/09/23)
A process for preparing trans-enriched MDACH, including: distilling an MDACH starting mixture in the presence of an auxiliary, which is an organic compound having a molar mass of 62 to 500 g/mol, a boiling point at least 5° C. above the boiling point of cis,cis-2,6-diamino-1-methylcyclohexane, and 2 to 4 functional groups, each of which is independently an alcohol group or a primary, secondary or tertiary amino group. The MDACH starting mixture includes 0 to 100% by weight of 2,4-MDACH and 0 to 100% by weight of 2,6-MDACH, based on the total amount of MDACH present in the MDACH starting mixture. The MDACH starting mixture includes both trans and cis isomers. Trans-enriched MDACH includes 0 to 100% by weight of 2,4-MDACH and 0 to 100% by weight of 2,6-MDACH, where the proportion of trans isomers in the mixture is higher than the proportion of trans isomers in the MDACH starting mixture.
Preparation method of N-alkyl diisopropanolamine
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Paragraph 0030-0037, (2017/04/27)
The invention discloses a preparation process of N-alkyl diisopropanolamine. The preparation process comprises the steps of respectively heating epoxypropane and N-alkylamine by virtue of a heat exchanger, mixing by virtue of a static mixer, introducing the mixture into a pipeline reactor for reaction, distilling out un-reacted N-alkylamine in a vacuum state, and rectifying out a small amount of N-alkyl monoisopropanolamine by virtue of a vacuum rectifying tower, so as to obtain N-alkyl diisopropanolamine. By synthesizing N-alkyl diisopropanolamine with the pipeline reactor, the preparation method has the advantages that the product quality is stable, by-products are few, the production efficiency is high, safety is high,the labor intensity of workers is low, the equipment investment is low, industrial continuous production is beneficially realized, and the like.
