Tanaka H, Oomori K, Hino R. Intercalation of n-alkyltrimethylammonium ions into layered calcium octyl phosphates thermally treated in vacuo.
J Colloid Interface Sci 2004;
273:685-9. [PMID:
15082410 DOI:
10.1016/j.jcis.2003.11.063]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2003] [Accepted: 11/21/2003] [Indexed: 10/26/2022]
Abstract
Layered calcium octyl phosphate (CH3(CH2)7OPO3Ca.1.6H2O: CaOP), which is composed of a multilayer alternating bilayer of octyl phosphates and a dicalcium phosphate dihydrate (DCPD)-like phase, was thermally treated in vacuo and the intercalation of n-alkyltrimethylammonium ions into the materials was examined. The octyl groups in the layer were eliminated by outgassing above 250 degrees C to give the amorphous calcium phosphates. Further, the specific surface area was steeply increased and mesopores with a diameter of ca. 2.0 nm were formed. IR results indicated that the surface P-OH groups were generated by outgassing at 250 degrees C. When the CaOP outgassed at 250 degrees C was treated with n-alkyltrimethylammonium ion solutions (carbon number of alkyl group, n=14-18), three XRD peaks reappeared below 2theta=15 degrees and the d-spacing ratio of these peaks was 1:1/2:1/3. These facts indicate that the n-alkyltrimethylammonium ions were intercalated into the amorphous calcium phosphate phases.
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