P-methylbenzoic Acid Research Articles

Removal of BTEX from water system by synergistic flocculation of biosurfactant and iron salt

The adsorption micelle flocculation (AMF) effect of biosurfactants (rhamnolipids, RL) and polymerized ferric sulfate (PFS) on the removal of low molecular weight benzoic acid (benzoic acid and p-methyl benzoic acid) and phenol (2,4-dichlorophenol and bisphenol A) organics was investigated. The coexistence system of RL and organic matter was constructed, and the effects of pH, Fe concentration, RL concentration and initial concentration of organic matter on the removal effect were discussed. For benzoic acid and p-methyl benzoic acid, the increase of Fe and RL concentrations was beneficial to their removal rates under weak acidic conditions, and the removal rate of the coexistence system was higher for methyl benzoic acid (87.7 %) than for benzoic acid (78.6 %), which might be attributed to the stronger hydrophobicity of the coexistence system for methyl benzoic acid; while for 2,4-dichlorophenol and bisphenol A, pH and Fe concentration changes had less effect on the removal rate, but the increase in RL concentration was favorable to the removal rate, which was 93.1 % and 86.7 % for BPA and 2,4-dichlorophenol, respectively. These findings provide feasible ideas and directions for the removal of organics by AMF using biosurfactants.

Inexpensive bioluminescent genosensor for sensitive determination of DNA damage induced by some commonly used sunscreens

Sunscreens (SSs) are highly applied all over the world on large areas of human body. Benzophenone chemical group constitute a major part in most SSs. Benzophenones are reported to induce changes in nucleic acids upon UV-irradiation. These alterations may potentially lead to DNA mutation, cell apoptosis, and eventually skin cancer. This work compares the kinetics of the induced DNA damage by some SSs after UV-irradiation. Six commonly used SSs; 4-t-butyl-4-methoxy dibenzoyl methane, 4-methoxycinnamic acid, 2-hydroxy-4-methoxybenzophenone (BZ-3), Dibenzoyl methane, 2,2′-dihydroxy-4-methoxy benzophenone (BZ-8) and p-methylbenzoic acid; are investigated. In this work, terbium chloride bioluminescent genosensor is used for sensitive, simple and inexpensive determination of induced DNA-damage. Results reveal that only BZ-3 and BZ-8 induced DNA-damage upon UV-irradiation that are confirmed by both absorption spectroscopy and viscosity measurements. Moreover, viscosity studies indicated the possible intercalation of the SS into DNA prior to initiation of DNA damage. Furthermore, the potency of BZ-3 and BZ-8 to induce DNA damage upon UVA irradiation was assessed on calf thymus DNA. The low cost of the proposed bioluminescent genosensor allows it to be an automatic simple process for the investigation of any DNA-drug interactions without the need of coupling with other analytical methods.

Conjugate Acid-Base Interaction Driven Phase Transition at a 2D Air-Water Interface.

A lattice model is described to explain a recent striking Sum Frequency Generation (SFG) observation of a cooperative surface adsorption effect for an organic acid system at an air-water interface. The reported anomalous pH-dependent enhancement in p-methylbenzoic acid (pmBA) arises from an interaction between the acid (HA) and its conjugate base anion (A-), which competes with strong Coulombic repulsion between the conjugate bases (A--A -). Using a statistical mechanical approach, this lattice gas model reveals an analogy to well-studied magnetic systems in which the attraction between the two different molecular species leads to a phase transition to a two-dimensional checkerboard phase consisting of a network of anion-acid complexes formed at the low-dielectric air-water interface. Cooperative acid-anion interactions that control partitioning at solution and aerosol interfaces are of interest to fields ranging from oceanic and atmospheric chemistry, pharmacology, and chemical engineering.

Spectral-Luminescent Properties of Mixed-Ligand Europium(III) Complexes with p-Methylbenzoic Acid

The spectral-luminescent properties of europium(III) complexes with p-methylbenzoic acid and nitrogen- and phosphorus-containing neutral ligands of compositions [Eu(p-MBA)3 · D]2 · xH2O and [Eu(p‑MBA)3 · 2H2O]n, where p-MBA is the anion of p-methylbenzoic acid and D is 1,10-phenanthroline (phen), 2,2' dipyridyl (dipy), triphenylphosphine oxide (tppo) (х = 0), hexamethylphosphortriamide (hmpa) (x = 1), or benzotriazole (bt) (x = 2) are studied. The electronic absorption spectra, the luminescence excitation spectra, and the Stark structure of 5D0−7Fj ( j = 0–2) electronic transitions in low-temperature luminescence spectra of complex europium(III) p-methylbenzoates are analyzed. It is found that the excitation energy transfer to europium ions occurs from the levels of both p-methylbenzoic acid and neutral ligands.

Mixed-Ligand Europium(III) Complexes with 4-Methylbenzoic Acid

Europium(III) complexes with p-methylbenzoic acid and nitrogen- or phosphorus-containing neutral ligand with the compositions [Eu(p-MBA)3·D]2·xH2O and [Eu(p-MBA)3·2H2O]n [where p-MBA is p-methylbenzoate anion and D is 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy), dimethylformamide (dmf), triphenylphosphine oxide (tppo), hexamethylphosphoramide (hmpa) (x = 1), or benzotriazole (bt) (x = 2)] have been synthesized, and their thermal decomposition has been studied.

Screening chemical modulators of benzoic acid derivatives to improve lipid accumulation in Schizochytrium limacinum SR21 with metabolomics analysis

BackgroundSchizochytrium sp. is a marine fungus with great potential as an alternative commercial source of lipids rich in polyunsaturated fatty acids (PUFAs). To further increase lipid accumulation in Schizochytrium sp., the effect of exogenous additives has become one of the hotspots of current research. Although benzoic acid derivatives showed positive effects on lipid accumulation in Schizochytrium, the biochemical mechanism needs further investigation.ResultsFour benzoic acid derivatives (sodium benzoate, p-aminobenzoic acid, p-methyl benzoic acid and folic acid) were screened and evaluated for their effect on lipid accumulation in Schizochytrium limacinum SR21. The lipid yield was increased by 56.84% with p-aminobenzoic acid (p-ABA) at a concentration of 200 mg/L among the four tested chemical modulators. The metabolomics analysis showed that 200 mg/L p-ABA was optimal for promoting glucose catabolism in glycolysis with an increase in the mevalonate pathway and a weakening of the tricarboxylic acid (TCA) cycle. Moreover, p-ABA increased NADPH generation by enhancing the pentose phosphate pathway (PPP), ultimately redirecting the metabolic flux to lipid synthesis. Fed-batch fermentation further proved that p-ABA could significantly increase the yield of lipid by 30.01%, reaching 99.67 g/L, and the lipid content was increased by 35.03%, reaching 71.12%. More importantly, the yields of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were increased by 33.28% and 42.0%, respectively.ConclusionThe addition of p-ABA could promote the synthesis of tetrahydrofolate, enhancing NADPH, which ultimately promoted the flow of carbon flux to lipid synthesis. These findings provide a valuable strategy for improving the lipid accumulation in Schizochytrium by additives.

Cladosporium cladosporioides from the perspectives of medical and biotechnological approaches.

Fungi are important natural product sources that have enormous potential for the production of novel compounds for use in pharmacology, agricultural applications and industry. Compared with other natural sources such as plants, fungi are highly diverse but understudied. However, research on Cladosporium cladosporioides revealed the existence of bioactive products such as p-methylbenzoic acid, ergosterol peroxide (EP) and calphostin C as well as enzymes including pectin methylesterase (PME), polygalacturonase (PG) and chlorpyrifos hydrolase. p-Methylbenzoic acid has ability to synthesise 1,5-benzodiazepine and its derivatives, polyethylene terephthalate and eicosapentaenoic acid. EP has anticancer, antiangiogenic, antibacterial, anti-oxidative and immunosuppressive properties. Calphostin C inhibits protein kinase C (PKC) by inactivating both PKC-epsilon and PKC-alpha. In addition, calphostin C stimulates apoptosis in WEHI-231 cells and vascular smooth muscle cells. Based on the stimulation of endoplasmic reticulum stress in some types of cancer, calphostin C has also been evaluated as a potential photodynamic therapeutic agent. Methylesterase (PME) and PG have garnered attention because of their usage in the food processing industry and significant physiological function in plants. Chlorpyrifos, a human, animal and plant toxin, can be degraded and eliminated by chlorpyrifos hydrolase.

The role of the host–guest interactions in the relative stability of compressed encapsulated homodimers and heterodimers of amides and carboxylic acids

A theoretical study has been carried out on the encapsulation of heterodimers and homodimers of p-methylbenzoic acid, p-ethylbenzoic acid, p-methylbenzamide, and p-ethylbenzamide molecules in reversible capsules with a very limited cavity. The drastic compression of the guests in the capsules has been studied by density functionally theory employing the M06-2X and ωB97X-D functionals with the 6-31G(d,p) basis set following preliminary calculations by the fast ONIOM[M06-2X/6-31G(d,p):PM6] methodology. Both functionals are in agreement with respect to the geometry, the interaction energies between the monomers and the relative ordering of the isomers. We found that encapsulation is favorable even for the larger p-ethyl compounds, but complexes of encapsulated dimers lie more than 4 kcal/mol above complexes with two non-interacting encapsulated monomers. The monomers prefer to be by themselves in the host. This is the reason why the present encapsulated dimers have not been found experimentally. The relative stability of the encapsulated complexes is reversed compared to complexes in a large cavity (Tzeli et al. in J Am Chem Soc 133:16977, 2012). This shows the possibility of separation of competitive guests via reversible encapsulation under appropriate conditions.

Syntheses, Crystal Structures and Magnetic Properties of Two Nickel(II) Compounds with 4,4´- Bipyridine Ligands

Hydrothermal reactions of 4,4´-bipyridine, benzoic acid/p-methylbenzoic acid, Ni(NO3)2 · 6H2O and NH4OH yielded [Ni(bpy)1.5(H2O)2(BA)2]·H2O (1) and [Ni(bpy)(HMBA)(MBA)2]n (2) (bpy = 4,4´-bipyridine, HBA = benzoic acid, HMBA = p-methylbenzoic acid). The Ni(II) ions of compound 1 are six-coordinated and bridged by 4,4´-bipyridine ligands to form a binuclear structure while complex 2 features polymeric chains which are connected by 4,4´-bipyridine molecules. Variabletemperature magnetic susceptibility measurements from 300 to 30 K showed the presence of weak ferromagnetic interactions between the Ni(II) (S = 1) ions via the 4,4´-bipyridine bridges.

Supramolecular Assembly and Ab Initio Quantum Chemical Calculations of 2-Hydroxyethylammonium Salts of para-Substituted Benzoic Acids

Crystal structures of seven salts of 2-hydroxyethylamine with benzoic acid (1) and different substituted benzoic acids, such as p-methylbenzoic acid (2), p-methoxybenzoic acid (3), p-hydroxybenzoic acid (4), p-chlorobenzoic acid (5), p-bromobenzoic (6), and p-iodobenzoic (7) have been studied. The salts units of 1–7 serve as building blocks (BB) of the supramolecular architecture. In a crystal they are held together via proton-transferred N–H···O and normal O–H···O hydrogen bonds. The substituents on anions influence dipole–dipole interactions between anions and cations in molecular aggregates. As a result, they are organized in building blocks either via one charge-assisted (1, 2) hydrogen bond or via two (3–7) hydrogen bonds. The dispersion interaction significantly contributes to intermolecular force fields driving the organization of hydrogen bonds in BB. In all studied compounds, building blocks are consolidated into 2-D layers through the N–H···O and O–H···O hydrogen bonds. For the crystal structure...

Metallo-deuteroporphyrin as a novel catalyst for p-xylene oxidation using molecular oxygen

The liquid phase oxidation of p-xylene with air as oxygen source catalyzed by metallo-deuteroporphyins [M(DPDME)], where M=Fe(III)Cl, Co(II), or Mn(III)Cl, were carried out in the absence of additives and solvents. Oxidation of p-xylene by M(DPDME) resulted in the formation of p-methylbenzaldehyde, p-methylbenzyl alcohol and p-methylbenzoic acid as major products. The complexed metals have an important effect on the activities of these metallo complexes and the distribution of the products. The oxidation reaction initiated by M(DPDME) was deemed to undergo a different path from metallo-tetraphenylporphyrins, and most of M(DPDME) may convert to μ-oxo dimmer as the active intermediate during the oxidation of p-xylene.

Coexistent Ag⋯Ag and Ag⋯C interactions in three photoluminescent silver(I) coordination networks based on o-, m-, p-methylbenzoic acid

Three new silver(I) coordination polymers (CPs) [Ag4(o-mba)4]n (1), [Ag2(m-mba)2]n (2) and [Ag2(p-mba)2]n (3) have been constructed from AgNO3 and three isomeric ligands, o-, m-, p-methylbenzoic acid (Hmba = methylbenzoic acid), and characterized by elemental analysis, infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. In 1, μ3–η1: η2 and μ4–η1: η3 o-mba ligands link Ag(I) ions to form a 1D chain based on a tetranuclear Ag(I) aggregation with a folded rhombus geometry. When the methyl group was moved from o- to m-position, we obtained 2 as a similar 1D chain but incorporating a parallelogram tetranuclear Ag(I) aggregation, where two crystallographically independent m-mba ligands show the identical μ3–η1: η2 coordination fashion. Using p-Hmba as ligand, complex 3 becomes a 2D (3,6) net with μ3–η1: η2 p-mba ligands. Interestingly, all CPs exhibit diverse Ag⋯Ag and Ag⋯C interactions, which are in the range of 2.7899(10)–3.3666(7) Å and 2.843(11)–3.336(10) Å, respectively. These secondary interactions cooperatively play important roles in the formation of the resulting 3D supramolecular frameworks. The structural dissimilarity can be mainly assigned to the change of relative positions of methyl and carboxyl groups. Moreover, the thermal stabilities and photoluminescence properties of 1–3 were investigated.

Solubilities of Benzene Carboxylic Acids in Isobutyl Acetate from (299.73 to 353.15) K

Solubilities of benzoic acid, p-methylbenzoic acid, o-phthalic acid, m-phthalic acid, and terephthalic acid in isobutyl acetate were measured in the temperature range from (299.73 to 353.15) K. The solubility data showed notable distinction in terms of different orders of magnitude. The experimental data were correlated by the universal quasichemical activity coefficient (UNIQUAC) model and the Wilson model. Generally, the UNIQUAC model was slightly superior to the Wilson model.

Spectroscopic properties of lanthanoid benzene carboxylates in the solid state: Part 1

Europium and terbium complexes of benzoic acid (HBA), 9-anthracene carboxylic acid (9-HACA), 1-naphthoic acid (1-HNA), 2-naphthoic acid (2-HNA), cinnamic acid (HCA), o-phenylbenzoic acid ( o-HPhBA), p-phenylbenzoic acid ( p-HPhBA), o-methylbenzoic acid ( o-HMeBA), m-methylbenzoic acid ( m-HMeBA), p-methylbenzoic acid ( p-HMeBA), p- tert-butylbenzoic acid ( p- tert HBuBA), phthalic acid (H 2Phth), isophthalic acid (H 2-IsoPhth) and terephthalic acid (H 2-TerePhth) were synthesised by aqueous metathesis reactions. The compositions were determined by microanalysis, DTA, and EDTA volumetric methods. Structural conclusions were drawn from powder XRD patterns and IR spectra. The optoelectronic properties were determined in the solid state, including reflectance, excitation, emission, and excitation efficiency, complemented by considering triplet state energies, which were derived from phosphorescence spectra of the corresponding gadolinium complexes. Besides the emission efficiencies, the splitting pattern of the 5D 0 → 7F J transitions of Eu 3+ were used to derive structural information and the intensities relative to the 5D 0 → 7F J were used to gain information about the mechanism, adding electronic allowed dipole character to the forbidden emissions.

Reactions of Quinazoline Alkaloids and their Derivatives with Electrophilic Reagents

Nitration of deoxypeganine (DOP), deoxyvasicinone (DOV), 2,3-tetramethylene-, 2,3-pentamethylene-, and 3,4-dihydroquinazol-4-ones and their 1,2-dihydro derivatives was studied. It was shown that the reaction pathway changed depending on the presence of a carbonyl on C-4 and an N=C bond in these compounds. Only the H atom on C-6 was subject to nitration if both functional groups were present, for example DOV and its homologs. Substitution of the H atom of either the 6-position (DOP, 1,2-dihydro-DOV, and their homologs) or the 6- and 8-positions simultaneously (DOP and its homologs) was enhanced if one of these functional groups was missing depending on the substrate:nitrating agent ratio. The bromination and nitration reactions of 1,2-dihydro-DOV and its analogs in a 1:2 ratio were accompanied by oxidation of the N 1 H-CH bond with formation of 6,8-dibromo- and 6,8-nitro-DOV and their homologs. The difference in the behavior of these compounds was due to the different nucleophilicity of the benzene rings in them. The reaction of 1,2-dihydro-DOV and its homologs with isocyanates and p-nitro- and p-methylbenzoic acid chlorides was studied. 6-Nitro- and 6,8-dinitro-DOP and 6,8-dibromo- and 6,8-dinitro-DOV and their homologs and 6-bromo- and 6-nitro-1,2,3,4-tetrahydro-2,3-polymethylenequinazol-4-ones and their 1-alkyl(aryl)-carbamoyl and p-nitro(methyl)-benzoyl derivatives were synthesized. The molecular structures of 1-ethyl-and 1-(o-chlorophenyl)-carbamoyl-1,2-dihydrodeoxyvasicinones and 6,8-dinitro-2,3pentamethylene-3,4-dihydroquinazol-4-one were established.

Solubilities of Benzoic Acid, p-Methylbenzoic Acid, m-Methylbenzoic Acid, o-Methylbenzoic Acid, p-Hydroxybenzoic Acid, and o-Nitrobenzoic Acid in 1-Octanol

Using a laser monitoring observation technique, the solubilities of benzoic acid, p-methylbenzoic acid, m-methylbenzoic acid, o-methylbenzoic acid, p-hydroxybenzoic acid, and o-nitrobenzoic acid in...

Hydrogen-Bonded Complexes of Carboxylate Anions and Dextrins in an Aprotic Polar Solvent

Complexation of p-methylbenzoate (p-CH3C6H4CO2−) and alkanoate anions (CnCO2−) with cyclodextrins (CDs) and acyclic dextrins (Gns) through hydrogen bonding in an aprotic polar solvent, [D6]DMSO, has been studied by means of 1H NMR spectroscopy. Although undissociated p-methylbenzoic acid, p-CH3C6H4CO2H, does not interact with dextrins, p-CH3C6H4CO2− binds through hydrogen-bonding interactions with fairly large binding constants (K) both to native CDs such as α-, β-, and γ-CDs and to Gns. Similar complexation was observed with CnCO2− anions. The K values are related to the basicity of the carboxylate anions. 1H NMR spectroscopy shows that the CO2− group of the guest interacts with the secondary OH groups at the vicinal 2- and 3-positions of the dextrins, while the primary OH groups do not participate at all. Formation of the hydrogen-bonded complex of β-CD and p-CH3C6H4CO2− is an entropically favorable process. Addition of a small amount of D2O suppresses the formation of the hydrogen-bonded complexes, suggesting that hydrogen-bonding interactions between simple hosts possessing dense OH groups as hydrogen-bond donors and guests with CO2− groups as hydrogen-bond acceptors hardly occur in aqueous solution.

Studies on Condensed Heterocyclic Compounds. XIII. 6-(4-Methylphenyl)-3-(1-naphthylmethylene)-s-triazolo[3,4-b][1,3,4]thiadiazole

6-(4-Methylphenyl)-3-(1-naphthylmethylene)-s-triazolo[3,4-b][1,3,4]thiadiazole, C21H16N4S, was prepared by cyclization of 3-(1-naphthylmethylene)-4-amino-5-mercapto-1,2,4-triazole with p-methyl benzoic acid in the presence of phosphorus oxychloride. The structure of the compound was determined by elemental analysis, IR and 1H NMR spectroscopy, and X-ray diffraction. The phenyl group and the heteronucleus are almost coplanar. The dihedral angle between the naphthyl group and the heteronucleus is 83.54 ± 0.06°.

Synthesis and Characterization of Bivalent Metal Complexes of Pyrrole-2-Carboxaldehyde Aroylhydrazones

Abstract The complexes of Co(II), Ni(II), Cu(II), Pd(II), Cd(II) and Zn(II) with hydrazones derived from benzoic, p-methylbenzoic or p-nitrobenzoic acid hydrazides and pyrrole-2-carboxaldehyde have been synthesized. The complexes have been characterized by elemental analyses, molar conductance, spectral (IR and visible) and magnetic studies. All the complexes are non-electrolytes. The IR spectral data show that the ligands act as neutral or monoanionic bidentates or as monoanionic tridentates. Spectral and magnetic studies suggest octahedral structures for all Co(II) and Ni(II) complexes, square-planar structures for [Cu(PBH)2], [Cu(PMBH)2].H2O and all Pd(II) complexes and a tetragonally distorted octahedral structure for [Cu(PNBH)2].

Dealkylation of esters via treatment with N-(trimethylsilyl) diethylamine and methyl iodide

A method for the conversion of esters to carboxylic acids has been reported. Reaction of methyl o-methoxybenzoate with N-(trimethylsilyl)diethylamine and methyl iodide, followed by hydrolysis, afforded o-methoxybenzoic acid with a 94% yield based on 96% conversion. Methyl esters of not only aromatic acids but also aliphatic acids were converted to the corresponding acids with high yields. A combination of N-(trimethylsilyl)dimethylamine and methyl iodide was also effective to give p-methylbenzoic acid with a 85% yield based on 90% conversion from the corresponding methyl ester.