P-31 AND AL-27 NMR INVESTIGATIONS OF HIGHLY ACIDIC, AQUEOUS-SOLUTIONS CONTAINING ALUMINUM AND PHOSPHORUS

被引:63
作者
MORTLOCK, RF
BELL, AT
RADKE, CJ
机构
[1] UNIV CALIF BERKELEY, DEPT CHEM ENGN, BERKELEY, CA 94720 USA
[2] LAWRENCE BERKELEY LAB, CTR ADV MAT, BERKELEY, CA 94720 USA
关键词
D O I
10.1021/j100105a039
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
P-31 and Al-27 NMR spectroscopies have been used to characterize acidic, aqueous solutions of orthophosphoric acid, aluminum chloride, and tetramethylammonium (TMA) hydroxide. The final compositions of the solutions range from 0.1 to 1 mol % P, 0.0 to 20 mol % HCI, P/Al = 0.1 to 20, and P/(TMA)20 = 2 to 20. Soluble aluminophosphate cations form reactions of hexaaqua Al monomeric cations, [Al(H20)6]3+, with phosphate ligands (i.e., H3PO4, H2PO4-, and acid dimers H6P2O8 and H5P2O7-). P-31 NMR spectra of aluminophosphate solutions reveal five distinct chemical shift regions. Free phosphate molecules and ions resonate at 3 to 5 ppm, P nuclei in acid dimers bonded to Al monomers resonate at -3.5 to -5.5 ppm, P nuclei in H2PO4- ions bonded to Al monomers resonate at -8.5 to -11 ppm, P nuclei in H3PO4 molecules bonded to Al monomers resonate at -11 to -13 ppm, and P nuclei bridging two Al monomers resonate at < 15 ppm. A correlation between the partial charge on P nuclei (calculated using semiemperical molecular orbital theory, MNDO [modified neglect of differential overlap]) and the P-31 NMR chemical shift confirms the assignments of the P-31 NMR resonances. Regardless of the total charge of the complex or the connectivity of the Al to -0-P units, the MNDO calculations show that P atoms in the same type of phosphate ligand bonded to Al monomers have similar partial charges, and, therefore, exhibit nearly identical P-31 chemical shifts. Al-27 NMR spectra of aluminophosphate solutions display four resonances: A peak at 0 ppm assigned to free Al monomers, a peak from -3 to -5 ppm assigned to Al monomers bonded to phosphate acid dimers, a peak from -6 to -7.5 ppm assigned to Al monomers bonded to H3PO4 molecules, and at peak from -7.5 to 9 ppm assigned to Al monomers bonded to H2PO4- ions. The assignment of the Al-27 NMR resonances is based on the manner in which the Al-27 and P-31 NMR peaks change in intensity with pH, P, and Al concentration. Estimates of the number of Al-O-P bonds are calculated independently from P-31 and Al-27 NMR spectra and agree quite closely for a range of pH's and both Al and P concentrations.
引用
收藏
页码:767 / 774
页数:8
相关论文
共 43 条
[1]   HYDROLYSIS AND DIMERISATION OF AQUEOUS ALUMINIUM SALT SOLUTIONS [J].
AKITT, JW ;
GREENWOOD, NN ;
LESTER, GD .
JOURNAL OF THE CHEMICAL SOCIETY D-CHEMICAL COMMUNICATIONS, 1969, (17) :988-+
[2]   AL-27 NUCLEAR MAGNETIC-RESONANCE STUDIES OF HYDROLYSIS AND POLYMERIZATION OF HEXA-AQUO-ALUMINUM(III) CATION [J].
AKITT, JW ;
LESTER, GD ;
KHANDELWAL, BL ;
GREENWOOD, NN .
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, 1972, (05) :604-+
[3]   NUCLEAR MAGNETIC RESONANCE AND RAMAN STUDIES OF ALUMINIUM COMPLEXES FORMED IN AQUEOUS SOLUTIONS OF ALUMINIUM SALTS CONTAINING PHOSPHORIC ACID AND FLUORIDE IONS [J].
AKITT, JW ;
LESTER, GD ;
GREENWOOD, NN .
JOURNAL OF THE CHEMICAL SOCIETY A -INORGANIC PHYSICAL THEORETICAL, 1971, (15) :2450-+
[4]   AL-27, P-31, AND SI-29 MAS NMR-STUDIES OF THE SILICOALUMINOPHOSPHATE MOLECULAR-SIEVE SAPO-5 [J].
APPLEYARD, IP ;
HARRIS, RK ;
FITCH, FR .
CHEMISTRY LETTERS, 1985, (11) :1747-1750
[5]  
Barrer R. M., 1982, HYDROTHERMAL CHEM ZE
[6]  
BJERRUM N, 1931, Z PHYS CHEM BODENSTE, P627
[7]   AL-27 AND P-31 NUCLEAR MAGNETIC-RESONANCE STUDIES OF ALUMINOPHOSPHATE MOLECULAR-SIEVES [J].
BLACKWELL, CS ;
PATTON, RL .
JOURNAL OF PHYSICAL CHEMISTRY, 1984, 88 (25) :6135-6139
[8]   SOLID-STATE NMR OF SILICOALUMINOPHOSPHATE MOLECULAR-SIEVES AND ALUMINOPHOSPHATE MATERIALS [J].
BLACKWELL, CS ;
PATTON, RL .
JOURNAL OF PHYSICAL CHEMISTRY, 1988, 92 (13) :3965-3970
[9]  
CHAKRABORTY AK, 1988, THESIS U DELAWARE
[10]  
CHESNUT DB, 1987, PHOSPHORUS 31 NMR PR