89-86-1Relevant articles and documents
Aqueous Kolbe-Schmitt synthesis using resorcinol in a microreactor laboratory rig under high-p,T conditions
Hessel, Volker,Hofmann,Loeb,Loehndorf,Loewe,Ziogas
, p. 479 - 489 (2005)
The aqueous Kolbe-Schmitt synthesis using resorcinol to yield 2,4-dihydroxy benzoic acid was performed in a microreactor rig. This small-scale plant was equipped initially with one capillary reactor and one microstructured cooler only. Later, two upgraded versions were constructed, having in addition a microstructured cooler and a microstructured mixer, respectively. The chemical protocol was significantly varied as compared to standard laboratory operation as described in the literature. Higher temperatures (up to 220°C) and pressures (up to 74 bar) were employed in a facile manner, termed high-p,T processing. In this way, the reaction time could be shortened by orders of magnitude, from about 2 hours to less than one minute, in some cases to some seconds. This resulted in a remarkable increase of the space-time yield by a factor of 440 at best. Productivity was in the L/h range and yielded at best 111 g/h product, corresponding to 4 t/a. Scale-out solutions are indicated. Drawbacks of the microreactor operation were also identified such as high sensitivity to fouling and delicate regulation of the system pressure, leading to partly unstable plant operation. Possibly even a considerable part of the product was rearranged to 2,6-dihydroxybenzoic acid and then thermally decomposed under the harsh reaction conditions. Solutions to overcome or at least diminish these restrictions are envisaged, and in the hope that this may be achieved, a process innovation and business perspective for the high-p,T microreactor processing is depicted.
Nonthermal Plasma-Induced Degradation of Morin and Enhancement of Biological Activities
Jeong, Gyeong Han,Kim, Tae Hoon
, (2020)
In the present study, non-thermal dielectric barrier discharge (DBD) plasma of induced structural changes of morin resulted in the isolation of one previously undescribed benzofuranone derivative, along with two known compounds. The chemical structures of
Bleach catalysis in aqueous medium by iron(III)-isoindoline complexes and hydrogen peroxide
Kaizer, József,Keszei, Soma,Lakk-Bogáth, Dóra,Meena, Bashdar I.
, p. 351 - 360 (2021/11/09)
Hydrogen peroxide and peroxymonocarbonate anion-based bleach reactions are important for many applications such as paper bleach, waste water treatment and laundry. Nonheme iron(III) complexes, [FeIII(L1?4)Cl2] with the 1,3-bis(20-Ar-imino)isoindolines ligands (HLn, n =1–4, Ar = pyridyl, thiazolyl, benzimidazolyl and N-methylbenzimidazolyl, respectively) have been shown to catalyze the oxidative degradation of morin as a soluble model of a bleachable stain by H2O2 in buffered aqueous solution. In these experiments the bleaching activity of the catalysts was significantly influenced by the Lewis acidity and redox properties of the metal centers, and showed a linear correlation with the FeIII/FeII redox potentials (in the range of 197–415 mV) controlled by the modification of the electron donor properties of the ligand introducing various aryl groups on the bis-iminoisoindoline moiety. A similar trend but with low yields was observed for the disproportionation of H2O2 (catalase-like reaction) which is a major side reaction of catalytic bleach with transition metal complexes. The effect of bicarbonate ions might be explained by the reduction of Fe(III) ions and/or the formation of peroxymonocarbonate monoanion, which is a much stronger oxidant and could increase the formation of the catalytically active high-valent oxoiron species.
Kolbe-Schmitt type reaction under ambient conditions mediated by an organic base
Sadamitsu, Yuta,Okumura, Akira,Saito, Kodai,Yamada, Tohru
supporting information, p. 9837 - 9840 (2019/08/20)
The combined use of an organic base for resorcinols realized a Kolbe-Schmitt type reaction under ambient conditions. When resorcinols (3-hydroxyphenol derivatives) were treated with DBU under a carbon dioxide atmosphere, nucleophilic addition to carbon dioxide proceeded to afford the corresponding salicylic acid derivatives in high yields.