Preparation of Aromatic Carboxylic Acids by Side-Chain Oxidation with Dilute Nitric Acid at High Temperature and Pressure.

Bengtsson, Erik B.; Nielsen, Erling Juhl; Reiter, Richard C.; Schønfeldt, E.; Steensgaard, Inger; Rosenberg, Th.

doi:10.3891/acta.chem.scand.07-0774

Cited by 9 publications

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“…The autoclave was sealed and heated at 180 °C for 3 d and then cooled to room temperature. Minor yellow blocklike product of DPTP-U1 suitable for X-ray studies was isolated along with colorless block crystal of DPTP ligand, which was confirmed by single-crystal and powder X-ray diffraction analyses (Table and Figure S1). Pure powder phase of DPTP-U1 could, however, be obtained by direct reaction of uranyl nitrate, DPTP ligand, and dipy under similar conditions.…”

Section: Methodsmentioning

confidence: 71%

“…It is noted that in both syntheses, nitric acid must be added, which not only keeps the strong acidic condition but also may serve as the oxidant. It is well-known that alkyl chain in aromatic compound can be oxidized to carboxylic group using nitric acid . For example, Tong et al recently reported nitric acid could in situ oxidize substituted methyl group on the pyridine ring into carboxyl. , Therefore, it is reasonable to expect a similar role may be played by nitric acid in the oxidation of DMPDP into DPTP.…”

Section: Resultsmentioning

confidence: 99%

“…As far as we know, most uranyl phosphonates were obtained under low pH, − which facilitates the oxidation of methyl group. (2) Nitrate from the metal salts and the protons in the solution including those added for adjusting pH can act as the oxidant. , (3) In addition to the phosphonate groups, the in situ generated carboxylate moieties can also bind uranyl centers to form intriguing uranyl hybrid coordination polymers. We herein report two novel uranyl carboxyphosphonates (H 2 dipy)[(UO 2 ) 3 (H 2 O) 2 (H 2 DPTP) 2 ]·2H 2 O ( DPTP-U1 ) and (H 2 bbi)[(UO 2 ) 4 (H 2 O) 2 (HDPTP) 2 ] ( DPTP-U2 ; H 6 DPTP = 2,5-diphosphonoterephthalic acid, dipy = 4,4′-bipyridine, bbi = 1,1′-(1,4-butanediyl)bis(imidazole)) that are derived from in situ ligand reaction under hydrothermal condition.…”

Section: Introductionmentioning

confidence: 99%

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Uranyl Carboxyphosphonates Derived from Hydrothermal in Situ Ligand Reaction: Syntheses, Structures, and Computational Investigations

Bai

Tian

et al. 2015

Inorg. Chem.

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Two uranyl carboxyphosphonates (H2dipy)[(UO2)3(H2O)2(H2DPTP)2]·2H2O (DPTP-U1) and (H2bbi)[(UO2)4(H2O)2(HDPTP)2] (DPTP-U2) [H6DPTP = 2,5-diphosphonoterephthalic acid, dipy = 4,4'-bipyridine, bbi = 1,1'-(1,4-butanediyl)bis(imidazole)] were synthesized under hydrothermal conditions. The carboxyphosphonate ligand was formed through the in situ oxidation of (2,5-dimethyl-1,4-phenylene)diphosphonic acid mediated by UO2(2+). Single-crystal X-ray diffraction analyses reveal that DPTP-U1 possesses uranyl carboxyphosphonate layers that are separated by protonated dipy cations. Whereas DPTP-U2 is in a three-dimensional framework structure with channels filled by protonated bbi cations. The computational investigations give an insight into the nature of bonding interactions between uranium(VI) and carboxyphosphonate ligand. The spectroscopic properties were also studied.

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Section: Methodsmentioning

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Uranyl Carboxyphosphonates Derived from Hydrothermal in Situ Ligand Reaction: Syntheses, Structures, and Computational Investigations

Bai

Tian

et al. 2015

Inorg. Chem.

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Über Pyromellitsäure‐ und Cumidinsäure‐Derivate. I. Teil

Hopff

Manukian

1960

Helvetica Chimica Acta

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In einigen alteren Arbeiten ist die Chlorierung von Durol (I) beschrieben wordenl). Wir haben diese Reaktion nachgepruft und stellen ebenfalls fest, dass bei einer sehr kurzen Chlorierungsdauer in der Kalte, in Gegenwart von katalytischen Mengen Jod, primar das Monochlordurol (11) entsteht. Dieses liefert dann bei weiterer Chlorierung das bekannte Dichlordurol (111). Die Isolierung und Reindarstellung des Monochlordurols aus dem Reaktionsgemisch erwies sich als sehr schwierig. Nach mehrmaliger Umkristallisation erhielten wir ein Gemisch, welches 75% Monochlordurol aufwies z). Das Dichlordurol (111) dagegen fallt direkt aus der Reaktionslosung kristallin aus. Wird das Dichlordurol in Petrolather suspendiert und bei Tageslicht weiter chloriert, so geht es in kurzer Zeit in Losung. Nach einer Weile fallt eine weisse, kristalline Masse der Bruttoformel C,,HloC1, aus. Das UV.-Absorptionsspektrum (vgl. Fig. 1, Kurve c) sowie das Verhalten der beiden zusatzlichen Chloratome gegen Alkali lassen darauf schliessen, dass die letzteren in die Seitenkette eingetreten sind; sie lassen sich mit verd. Watronlauge quantitativ abspalten 3). Fur die Tetrachlorverbindung standen deshalb die drei Formeln a, b und IV zur Diskussion. Die Konstitution entsprechend IV wurde auf folgende Weise aufgeklart :Nach bekannter Methode wurden p-Xylol und m-Xylol chlormethyliert 4)5)6). Die dabei erhaltenen Verbindungen X und X I wurden in Petrolather, in Gegenwart von katalytischen Mengen Jod, chloriert. Die aus 1,4-Dimethyl-2, 5-bis-chlormethylbenzol (X) erhaltene neue Chlorverbindung ergab im Mischschmelzpunkt mit unserem tetrachlorierten Durol keine Depression. Sowohl die 1R.- (Fig. 2) als auch die UV.-Absorptionsspektren der beiden Produkte waren identisch. Demnach handelt es sich bei unserem chlorierten Durol urn das unbekannte 1,4-Dimethyl-2, 5-bischlormethyl-3,6-dichlor-benzol (IV). Erwartungsgemass erhielt man bei der Chlorierung von 1,5-Dimethyl-2, 4-bis-chlormethyl-benzol (XI) die ebenfalls unbekannte Verbindung XII.

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