The Effect of Dicarboxylic Acid Catalyst Structure on Hydrolysis of Cellulose Model Compound D-Cellobiose in Water

Background: Polycarboxylic acids are of interest as simple mimics for cellulase enzyme catalyzed depolymerization of cellulose. In this study, DFT calculations were used to investigate the effect of structure on dicarboxylic acid organo-catalyzed hydrolysis of cellulose model compound D-cellobiose to D-glucose. Methods: Binding energy of the complex formed between D-cellobiose and acid (Ebind), as well as glycosidic oxygen to dicarboxylic acid closest acidic H distance were studied as key parameters affecting the turn over frequency of hydrolysis in water. Result: α-D-cellobiose - dicarboxylic acid catalyst down face approach showed high Ebind values for five of the six acids studied; indicating the favorability of down face approach. Maleic, cis-1,2-cyclohexane dicarboxylic, and phthalic acids with the highest catalytic activities showed glycosidic oxygen to dicarboxylic acid acidic H distances 3.5-3.6 Å in the preferred configuration. Conclusion: The high catalytic activities of these acids may be due to the rigid structure, where acid groups are held in a fixed geometry.

Beyond conventional construction of phthalimide core: A review

Phthalimides are privileged structural motif frequently found in natural products, pharmaceuticals and organic materials. The Most common strategy for their synthesis involves condensation of phthalic acids/anhydrides with primary amines. However,...

INFLUENCE OF SUBSTITUTES ON THE RATE OF THE REACTION OF META- АND PARASUBSTITUTED BENZOIC ACIDS WTH ANILINE, CATALYZED BY POLYBUTOXYTITANATES

The polybutoxytitanates catalysis of acylation of anilines by meta- and parasubstituted benzoic acid results in substituted benzanilides. The rate constants of this second-order reaction (the first in terms of aniline and substituted benzoic acid; boiling ortho-xylene, 145 °С) correlates well according to the Hammett equation with two straight lines for individual groups of substituents with ρ = 1.76 (electron donors) and 0.12 (electron acceptors). Oxybenzoic and phthalic acids, that do not react with aniline and inhibit the interaction of the latter with benzoic acid, fall out of this dependence. Based on these data, as well as the results of a previous studies of the interaction of substituted anilines with a benzoic acid made under comparable conditions, a mechanism of bifunctional catalysis due to the formation of titanium polybutoxybenzoates in the first minutes of the reaction in situ — the true catalysts of the process, is proposed. The nucleophilic center of the catalyst can be represented by the carbonyl group of a substituted benzoate bound to a titanium atom, forming an H-bond with hydrogen atoms of the amino group of aniline, thus activated to react with a substituted benzoic acid. The titanium atoms of polytitanate (coordination catalysis) and their complexes with the resulting substituted benzanilides (acid catalysis) can act as the electrophilic center of a catalyst that activates the carbonyl group of a substituted benzoic acid to nucleophilic attack by aniline. A titanium atom bound to a substituted benzoate exhibits, depending on the nature of the substituent, various catalytic activity.

Visual discrimination of aromatic acid substitution patterns by supramolecular nanocooperativity

Recognition and visualization of all isomers of phthalic acids by interactions with pillar[4]pyridinium and gold nanoparticles is reported.

Methods for the synthesis of dichloroanhydrides of phthalic acids

Dichloroanhydrides of isophthalic (isophthaloyl chloride) and terephthalic (terephthaloyl chloride) acids are, undoubtedly, strategically important compounds. Among their main application areas is synthesis of Aramid fibers to be used for manufacturing dual use materials including synthesis of Terlon®, Phenylon®, Armos®, Tegelen®, SVM®, and Rusar® fibers. Specific requirements for quality of the target anhydrides and feedstock determine the choice of the synthetic methods. In the review paper, various methods, including catalytic methods, for the synthesis of iso- and terephthaloyl chlorides based on the use of different types of feedstock are discussed. Main methods for analysis of these compounds are described in detail.

The Physiological and Biochemical Effects of Phthalic Acids and the Changes of Rhizosphere Fungi Diversity under Continuous Cropping of Lanzhou Lily (Lilium davidii var. unicolor)

The autotoxicity of root exudates and the change of rhizosphere soil microbes are two important factors that affect the quality and yield of Lanzhou lily (Lilium davidii var. unicolor). Phthalic acid (PA) is a major autotoxin of the root exudates in Lanzhou lily. In this study, we treated plants with different concentrations of PA from the Lanzhou lily root exudates and then analyzed the effects of autotoxins on fresh weight, shoot height, root length, and Oxygen Radical Absorbance Capacity in root. The diversity of soil fungi in Lanzhou lily soil was analyzed using MiSeq. The results showed that PA induced oxidative stress and oxidative damage of Lanzhou lily roots, improved the level of the membrane lipid peroxidation, reduced the content of antioxidant defense enzyme activity and the nonenzymatic antioxidant, and eventually inhibited the growth of the Lanzhou lily. We found that continuous cropping of Lanzhou lily resulted in an increase in fungal pathogens, such as Fusarium oxysporum in the soil, and reduced the size of plant-beneficial bacteria populations. The results in this study indicate that continuous cropping would damage the regular growth of Lanzhou lily.