Alkaline hydrolysis of dimethyl terephthalate in the presence of [LiAl2(OH)6]Cl·2H2O

Lei, Lixu; Zhang, Weifeng; Hu, Meng; Zheng, He‐Gen

doi:10.1016/j.jssc.2006.07.038

Cited by 6 publications

(5 citation statements)

References 14 publications

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“…Monovalent ions such as Li + may fill 100% of the vacancies resulting in the ideal chemical composition of [LiAl 2 (OH) 6 ] + [A n – ] 1/ n · n H 2 O. Both inorganic and organic Li + salts have been used as starting materials for insertion of Li + into gibbsite − and bayerite. ,,, In 2004 a new subclass of Al(OH) 3 -LDHs was obtained by incorporation of divalent cations (M(II) = Ni(II), Co(II), Zn(II), and Cu(II)) filling up to half the vacancies in the parent gibbsite structure . This was achieved by hydrothermal treatment of a physical mixture of activated gibbsite with an excess of M(II) salts .…”

Section: Introductionmentioning

confidence: 99%

“…5 Two classes of LDHs are known. The first can be viewed as divalent metal hydroxides (M(II) (OH) 2 ) with partial substitution of the divalent ions (M(II)) by trivalent cations (M(III)) accompanied by insertions of anions and water in the interlayer, that is, "hydrotalcite-type" named after the mineral hydrotalcite [Mg 6 Al 2 (OH) 16 x/n mH 2 O] (where M(II) = Mg 2+ , Ca 2+ , Zn 2+ , Fe 2+ , Co 2+ , ..., M(III) = Al 3+ , Fe 3+ , Co 3+ , Ga 3+ , and A n− is an inorganic or organic anion) have been developed. The flexible chemistry of the cation layers in combination with a vast number of possible anions ranging from simple anions such as halides or oxyanions to complex organic anions or biomolecules account for their popularity and widespread applications.…”

Section: ■ Introductionmentioning

confidence: 99%

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Structural Investigation of Zn(II) Insertion in Bayerite, an Aluminum Hydroxide

et al. 2016

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Bayerite was treated under hydrothermal conditions (120, 130, 140, and 150 °C) to prepare a series of layered double hydroxides (LDHs) with an ideal composition of ZnAl4(OH)12(SO4)0.5·nH2O (ZnAl4-LDHs). These products were investigated by both bulk techniques (powder X-ray diffraction (PXRD), transmission electron microscopy, and elemental analysis) and atomic-level techniques ((1)H and (27)Al solid-state NMR, IR, and Raman spectroscopy) to gain a detailed insight into the structure of ZnAl4-LDHs and sample composition. Four structural models (one stoichiometric and three different defect models) were investigated by Rietveld refinement of the PXRD data. These were assessed using the information obtained from other characterization techniques, which favored the ideal (nondefect) structural model for ZnAl4-LDH, as, for example, (27)Al magic-angle spinning NMR showed that excess Al was present as amorphous bayerite (Al(OH)3) and pseudoboehmite (AlOOH). Moreover, no evidence of cation mixing, that is, partial substitution of Zn(II) onto any of four Al sites, was observed. Altogether this study highlights the challenges involved to synthesize pure ZnAl4-LDHs and the necessity to use complementary techniques such as PXRD, elemental analysis, and solid-state NMR for the characterization of the local and extended structure of ZnAl4-LDHs.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Structural Investigation of Zn(II) Insertion in Bayerite, an Aluminum Hydroxide

et al. 2016

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“…The Li−Al LDHs are unique among the wider class of layered hydroxides, for their important applications in catalysis and in particular their tendency to exhibit shape-selective intercalation of anions. − It is suggested that the origin of this shape selective intercalation lies in the unique structure of this material and in the cation ordering within the layers. A knowledge of the structure of the bayerite-based Li−Al LDHs should throw some light into these phenomena.…”

Section: Introductionmentioning

confidence: 99%

Structure of Bayerite-Based Lithium−Aluminum Layered Double Hydroxides (LDHs): Observation of Monoclinic Symmetry

Britto

Kamath

2009

Inorg. Chem.

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The double hydroxides of Li with Al, obtained by the imbibition of Li salts into bayerite and gibbsite-Al(OH)(3), are not different polytypes of the same symmetry but actually crystallize in two different symmetries. The bayerite-derived double hydroxides crystallize with monoclinic symmetry, while the gibbsite-derived hydroxides crystallize with hexagonal symmetry. Successive metal hydroxide layers in the bayerite-derived LDHs are translated by the vector ( approximately -1/3, 0, 1) with respect to each other. The exigency of hydrogen bonding drives the intercalated Cl(-) ion to a site with 2-fold coordination, whereas the intercalated water occupies a site with 6-fold coordination having a pseudotrigonal prismatic symmetry. The nonideal nature of the interlayer sites has implications for the observed selectivity of Li-Al LDHs toward anions of different symmetries.

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“…The precipitation of aluminum trihydroxides is considered a crucial step in the Bayer process therefore several syntheses start from highly concentrated sodium or potassium aluminate solutions [22][23][24] . Recently, bayerite has received attention in the preparation of a prominent class of materials, namely layer double hydroxides, LDH [25][26][27] . Bayerite has been synthesized by ageing the alumina gels in water, acidification of aluminate solutions by use of HClO 4 , HNO 3 and or CO 2 , and from aluminum powder in alkaline media [28][29][30][31] .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and properties of new paramagnetic hybrid bayerite from Al(0)/naphthalene dianhydride reaction

et al. 2010

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The reaction of Naphthalene 1,4,5,8-dianhydride (NTCDA) with elemental aluminum(0) powder is studied in an aqueous alcoholic KOH mixture to search for the NTCDA anion and dianion electron-adducts. After analyzing various reaction conditions it was found that the reaction yielded a greenish precipitate in 3:1 (v:v) ethanol:water mixture. This powder is composed mainly of aluminum trihydroxide crystallites of bayerite [a-Al(OH 3 ) (s) ] and the organic content is approximately 6%. This hybrid material proved to be paramagnetic even after exposure to air for one year and at temperatures up to 200 °C. Typical carbonylic bound to metal IR bands and reflectance UV-VIS spectra demonstrate the entrapment of NTCDA radical anion into the aluminum trihydroxide, hence rendering its green color and a paramagnetic behavior. Thus, besides the understanding of an aluminum reaction in suspension, the entrapment of an organic material (NTCDA) that stays stable as the corresponding radical can provide an interesting option for the synthesis of aluminum trihydroxide composites.

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Alkaline hydrolysis of dimethyl terephthalate in the presence of [LiAl2(OH)6]Cl·2H2O

Cited by 6 publications

References 14 publications

Structural Investigation of Zn(II) Insertion in Bayerite, an Aluminum Hydroxide

Structural Investigation of Zn(II) Insertion in Bayerite, an Aluminum Hydroxide

Structure of Bayerite-Based Lithium−Aluminum Layered Double Hydroxides (LDHs): Observation of Monoclinic Symmetry

Synthesis and properties of new paramagnetic hybrid bayerite from Al(0)/naphthalene dianhydride reaction

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