COOCH3 Group Research Articles

Enhancing Pectin Particles with Polymer Additives: Mitigating Rumen Degradation and Minimizing Yellowish Milk Color in Grazed Cows.

The pigments consumed in grazing give the milk from dual-purpose cows raised in tropical conditions a yellowish color, affecting the quality and price of the milk. This study aimed to develop an economical method with supplementary pectin to antagonize the availability of carotenes by designing microparticles with shellac and palm oil as a viable alternative to protect pectin degradation against rumen microbes. Three preparations of microparticles based on citrus pectin were synthesized: unprotected (PnP), protected with palm oil (PwP), and protected with palm oil and shellac (PwPL) microparticles. Samples were roughly characterized by spectroscopy and electron microscopy techniques. The effect of PnP, PwP, and PwPL on blood metabolites and physicochemical characteristics of the milk of grazing lactating cows was evaluated through in vivo assays. The release of citrus pectin from microparticles was determined as uronic acids using solutions with distinct pH, whereas its degradation was studied using in situ tests. Results revealed that PnP, PwP, and PwPL are amorphous structures with sizes that range from 60 to 265 nm or 750 to 3570 µm and have surface charges that range from -11.5 to -50.2 mV. Samples exhibited characteristic peaks during FTIR analyses that corresponded to O-H, C=O, and COOCH3 groups and bands within the UV-vis region that indicated the absorption of pectin. The EDS analysis revealed the presence of carbon, oxygen, or calcium in samples. The release of uronic acids was higher at pH 2-3 with PwPL. The in situ degradability of PnP, PwP, and PwPL was 99, 28.4, and 17.7%, respectively. Moreover, PwPL decreased the blood concentration of glucose, cholesterol, and lactate. In contrast, 100 g of pectin per animal daily during the feed process reduced yellow coloring. In conclusion, designing particles protected with lipids and polymers as shellac is an economical method that resists degradation at pH levels greater than five.

Rapid detection of Ag+ in food using cholesteric chiral artificial receptor L5

A cholesteric chiral artificial receptor L5 was synthesized, which recognized and cooperated with Ag+ in metal ions, and a rapid method for detecting Ag+ was established in food. It was found by fluorescence spectroscopy analysis that the L5 could recognize Ag+ in DMSO solution; with the help of fluorescence and UV titration, job test and interference test to verify its recognition pattern, and founded that the L5 and guest Ag+ were combined with 1:1 coordination ratio. Then, the recognition mechanism between L5 and guest Ag+ was explored by measures of nuclear magnetic titration, infrared spectroscopy, electron microscopy and computer molecular simulation. It was speculated that the carbonyl oxygen atom near the amide of the MeO-PhCONH group and the carbonyl oxygen atom of the –COOCH3 group cooperated with Ag+ throµgh electrostatic gravitational interaction. This method was used to establish the detection of Ag+ in food in which the detection limit of L5 for Ag+ was derived as 0.13 µmol/L, and the silver ions in wolfberry, milk powder,wheat flour, tea leaf and soybean were accurately detected. This method can be used to quantify Ag+ content in actual samples accurately and efficiently.

Janus ZIF-8/P(AN-MA) hybrid microfiltration membrane with selected wettability for highly efficient separation of water/oil emulsions

The separation of oil-in-water and water-in-oil emulsions with high efficiency and environmental friendly remains a challenge in the past decade. This work describes a new method to improve the trade-off of the poly(acrylonitrile-co-methyl acrylate) (P(AN-MA))-based membrane for water/oil separation. P(AN-MA) microfiltration (MF) membrane was fabricated via thermally induced phase separation (TIPS) method in this study. Then, some of the –CN groups and –COOCH3 groups were converted to –COOH groups via hydrolyzing. Finally, the selected wettability was attained by grafting PEI on one side while ZIF-8 was anchored to the other side via self-assembly and in-situ interfacial reaction methods. The ZIF-8/P(AN-MA) hybrid MF membranes are superoleophobic underwater on the PEI side while super-hydrophobic under oil on the ZIF-8 side, which can efficiently and accurately separate oil-in-water and water-in-oil emulsions at a low pressure (0.01 MPa). The separation fluxes of the PEI side were as high as 3053 L/m2 h and 1035 L/m2 h respectively, for the surfactant-free mixtures and surfactant-stabilized emulsions. For water-in-oil emulsions, the fluxes were up to 2316 L/m2 and 878 L/m2 h on the ZIF-8 side, respectively. The separation efficiency of all the mixtures and emulsions was higher than 97.5 %. Moreover, the Janus membranes showed excellent anti-oil-fouling and anti-water-fouling properties on the two sides of the membranes, as well as remarkable durability during the 10 cycles in oil/water separation. Hence, Janus ZIF-8/P(AN-MA) hybrid MF membranes show potential application prospects in oil/water separation.

Synthesis and characterization of photo-crosslinkable cinnamate-functionalized pectin

The polysaccharide pectin (PC) was functionalized with the photo-responsive cinnamic acid hydrazide (CN) to produce the photo-crosslinkable PC-CN hydrogel material that was then evaluated as a carrier for encapsulation of the drug model aspirin. Cinnamic acid hydrazide was first prepared and then incorporated with the abundant –COOCH3 groups on the pectin chain via hydrazide linkage. The obtained polymeric derivatives have been characterized by means of instrumental techniques including FTIR and NMR. The obtained PC-CN hydrogels with different cinnamic functionality were also freeze-dried and examined by SEM, which indicated more coherent hydrogel texture by increasing the cinnamic functionalization. The effect of the photo-curing time, as well as the functionalization degree, on the swelling and gelation of the obtained hydrogel was also studied to evaluate the potential of the developed material in drug delivery systems using aspirin as a common and available drug model. The developed PC-CN hydrogel materials exhibited high potential as a drug carrier that enables the control of the drug release via optimizing both the degree of cinnamic functionality and the photo-curing time.

Experimental and kinetic modeling studies of furfural pyrolysis at low and atmospheric pressures

Furfural (2-furaldehyde) is a promising platform chemical for lignocellulosic biofuels, but its thermal decomposition channels are not well understood. To better understand furfural thermal decomposition kinetics, flow tube reactor pyrolysis combined with synchrotron vacuum ultraviolet photoionization mass spectrometry at low and atmospheric pressures and temperatures from 929 to 1365 K was investigated. Carbon monoxide, methane, acetylene, propyne, allene, furan, and vinylketene as the main products were detected and measured. A detailed kinetic model for furfural pyrolysis consisting of 585 species and 3018 reactions was built based on the potential energy surface, and validated against the experimental data from the current and previous studies. Rate of production analysis shows that furfural mainly underwent unimolecular non-radical decomposition channel to form vinylketene and carbon monoxide. Sequential decomposition of vinylketene led to the production of allene, propyne and carbon monoxide, etc. H-atom addition reactions on the furan ring was the main source of furan. HCO, CH3 and COOCH3 groups influence the decomposition pathways of furanic fuels, and accelerate their decomposition with decomposition temperatures in the sequence of methyl 2-furoate < furfural < 2,5-dimethylfuran < 2-methylfuran < furan.

N‐Confused Porphyrin – A Unique “Turn‐On” Chemosensor for CN− and F− ions and “Turn‐Off” Sensor for ClO4− ions

N-Confused meso-tetrakis(4-carbomethoxyphenyl)porphyrin (1) and its Ni(II) complex (1 a) have been synthesized and utilized for anion sensing studies, and the results are compared with N-confused meso-tetraphenylporphyrin (NCTPP). Anion susceptibilities of 1 and 1 a were investigated using spectroscopic, electrochemical, and DFT studies. Porphyrins 1 and 1 a were able to detect CN- , F- , and ClO4 - ions selectively over the tested set of anions even at ppm level. Interestingly, the addition of ClO4 - ions resulted in fluorescence quenching (turn off) whereas the addition of F- or CN- resulted in fluorescence enhancement (turn on). Notably, the TFA addition resulted in fluorescence quenching, whereas the fluorescence enhancement was observed while adding TBAOH. The higher association constant (Ka ) values with anions, lower detection limit, and shifts in redox potentials are due to the electron-withdrawing effect of the -COOCH3 group at the para-position of the meso-phenyl ring. This electron-withdrawing nature is crucial for the higher affinity towards anions. The anion sensing description in this article may not only unveil the built-in nature of N-confused porphyrins, but may also provide a general proposal for the development of novel anion sensors based on porphyrinoids. The electron-deficient porphyrin framework, large polarisable π-system, and anion binding through the outer NH or a combination of the above factors serve as a foundation for N-confused porphyrin to act as an anion sensor.

Preparation and fluorescence properties of novel 2-quinolone derivatives and their corresponding Eu(III) complexes

A series of novel 2-quinolone ligands and their corresponding Eu(III) complexes were prepared. The effect of different solvents, different ligand concentrations and different substituents on the fluorescence intensity of ligands were investigated in detail. The fluorescence intensity of Eu(III) complexes were studied by comparing different substituents on the ligand. The results indicate that all ligands show the strongest fluorescence intensity in ethanol with the ligand concentration of 50 μM. Among these ligands, the ligand (K6) containing -COOCH3 group owns the strongest fluorescence intensity and the corresponding fluorescence quantum yield reaches 0.317. All complexes exhibit characteristic red light of Eu(III) ions with good thermal stability. The effect of diverse substituents on the fluorescence intensity is ordered: -COOCH3>-Cl> -Br> -OCH3>-CH3>-H, which indicates the complex [EuK6(NO3)3]·2H2O with the strongest electron-donating group (-COOCH3) possesses the strongest fluorescence intensity. The above analysis shows that the ligand (K6) and corresponding Eu(III) complex [EuK6(NO3)3]·2H2O own the best fluorescence property, which has an outstanding application prospect in the field of optical materials and biomedicine materials.

Fluorescent microspheres of zinc 1,2-dicarbomethoxy-1,2-dithiolate complex decorated with carbon nanotubes

A new discrete bis-dithiolene complex, [PPh4]2[Zn(DMED)2] (1; DMED = 1,2-dicarbomethoxy-1,2-dithiolate) with sulfur-based radical character was synthesized and structurally characterized. Complex 1 is stable and exhibits a square planar geometry around the zinc metal. 1 forms nanospheres through a one-pot water-induced self-assembly in a mixture of solvents (acetonitrile–water). These nanospheres were further decorated with water-soluble carbon nanotubes (wsCNTs) through hydrogen bonding between the peripheral –COOCH3 groups of 1 and surfacial carboxyl groups of wsCNTs to assemble into a spherical nanocomposite. The as-prepared nanocomposite showed fluorescence emissions in visible region due to the separation of energy states of the nanospheres assisted by wsCNTs, suggesting the future possibilities of these new materials for use in biomedical application.

Stabilization of perfluorinated ethylene-propylene by esterification with short-chain alcohols

The perfluorinated ethylene-propylene (FEP) having unstable end groups (–COOH, –COF and –CF=CF2) were stabilized via esterification with short-chain alcohols. The effect of different alcohols on the esterification of FEP was evaluated by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis with mass spectrometry (TGA-MS). The results of IR indicated that the end-capping using methanol at 140 °C (FEP-M140) got the much better effect in converting the labile end groups of FEP into –COOCH3 group with high stability, which was further proven by TG-MS that more weight loss together with more evolved CO2 gas for FEP compared with FEP-M140 were detected. It was very visual that more bubbles caused by the evolved gas distributed in FEP than FEP-M140 films during hot processing, further confirming the end-capped FEP displayed better thermal stability than the uncapped one.

Rhenium-Loaded TiO2 : A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2.

Herein, we report a heterogeneous TiO2 -supported Re catalyst (Re/TiO2 ) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2 . Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.

Relationships between fusion, solution, vaporization and sublimation enthalpies of substituted phenols

In this work a method for determination of sublimation and vaporization enthalpies of substituted phenols was developed. This method is a modification of solution calorimetry approach. Modification is based on the novel relations, which bind solution, vaporization and sublimation enthalpies at 298.15K and fusion enthalpy at the melting temperature. According to novel relations the equations for calculating sublimation and vaporization enthalpies at 298.15K were offered. Calculated values of sublimation and vaporization enthalpies of phenol derivatives containing alkyls, halogens, –OCH3, –NO2, –COCH3, –COOCH3 groups, and dihydroxybenzenes were compared with literature data (298.15K) obtained by conventional methods. In most of the cases divergence does not exceed 2–3%.

Structural and spectroscopic study of a pectin isolated from citrus peel by using FTIR and FT-Raman spectra and DFT calculations

In this work, pectin isolated from citrus peel with a degree of esterification of 76% was characterized by Fourier Transform Infrared (FTIR) and Fourier Transform Raman (FT-Raman) spectroscopies. Structural studies were carried out taking into account their partial degree of esterification and considering the polygalacturonic acid chain as formed by two different subunits, one with both COOH and COOCH3 groups (Ac) and the other one as constituted by two subunits with two COOCH3 groups (Es). Their structural properties, harmonic frequencies, force fields and force constants in gas and aqueous solution phases were calculated by using the hybrid B3LYP/6-31G∗ method. Then, their complete vibrational analyses were performed by using the IR and Raman spectra accomplished with the scaled quantum mechanical (SQM) methodology. Reactivities and behaviors in both media were predicted for Ac and Es by using natural bond orbital (NBO), atoms in molecules (AIM), and frontier orbitals calculations. We report for first time the complete assignments of those two different units of polygalacturonic acid chain which are the 132 normal vibration modes of Ac and the 141 normal vibration modes of Es, combining the normal internal coordinates with the SQM methodology. In addition, three subunits were also studied. Reasonable correlations between the experimental and theoretical spectra were obtained. Thus, this work would allow the quick identification of pectin by using infrared and Raman spectroscopies and also provides new insight into the interactions that exist between subunits of a large pectin chain.

Synthesis and structure-activity relationship studies of novel 3,9-substituted α-carboline derivatives with high cytotoxic activity against colorectal cancer cells

In our continued focus on 1-benzyl-3-(5-hydroxymethyl-2-furyl)indazole (YC-1) analogs, we synthesized a novel series of 3,9-substituted α-carboline derivatives and evaluated the new compounds for antiproliferactive effects. Structure activity relationships revealed that a COOCH3 or CH2OH group at position-3 and substituted benzyl group at position-9 of the α-carboline nucleus were crucial for maximal activity. The most active compound, 11, showed high levels of cytotoxicity against HL-60, COLO 205, Hep 3B, and H460 cells with IC50 values of 0.3, 0.49, 0.7, and 0.8 μM, respectively. The effect of compound 11 on the cell cycle distribution demonstrated G2/M arrest in COLO 205 cells. Furthermore, mechanistic studies indicated that compound 11 induced apoptosis by activating death receptor and mitochondria dependent apoptotic signaling pathways in COLO 205 cells. The new 3,9-substituted α-carboline derivatives exhibited excellent anti-proliferative activities, and compound 11 can be used as a promising pro-apoptotic agent for future development of new antitumor agents.

Influence of carboxylic group or methyl ester group on the interactions of copper cation with aromatic system of naproxen, naphthalene acetic acids and their methyl esters

Solutions containing naproxen, its methyl ester and Cu2+, or naphthalene acetic acid, its methyl ester and Cu2+ was analyzed by using electrospray ionization mass spectrometry. As a result of interaction between Cu2+ and aromatic system (Cu2+–π interaction), the respective molecular ions were obtained. The interactions of Cu2+ with –COOH and –COOCH3 groups compete with that of Cu2+ with naphthalene rings, affecting the formation of molecular ions. Because of inductive effect of –CH3 moiety, –COOCH3 group interacts with Cu2+ stronger than –COOH group. ESI mass spectrum obtained for a mixture of isotopically labeled 1-naphthalene acetic acid methyl ester, 2-naphthalene acetic acid methyl ester and Cu2+ showed that second isomer is more prone to form molecular ions than the first.

Nanospheres of copper(iii) 1,2-dicarbomethoxy-1,2-dithiolate and its composite with water soluble carbon nanotubes

We report here the synthesis and structural characterization of a new discrete bis-dithiolene complex, [PPh4][Cu(DMED)2] (1; DMED = 1,2-dicarbomethoxy-1,2-dithiolate), involving the reaction between a copper polysulfide precursor with activated acetylene. 1 is stable, showing a sulfur-based radical character, as observed by electronic, EPR and cyclic voltammetric studies. This complex, possessing terminal –COOCH3 groups, forms nanospheres by hydrogen bonding in a mixture of solvents containing water as one of the components. These nanospheres further aggregate with water soluble (carboxylated) carbon nanotubes (wsCNTs). These nano-composites are assisted by hydrogen bonding between the carboxylic acid groups of the wsCNTs and the peripheral –COOCH3 groups of the coordinated dithiolenes of the nanospheres, which is promoted by water molecules. Interaction between the nanospheres on wrapping with wsCNTs, in forming the nano-composites, showed a perturbed EPR signal of the sulfur radical originating from the oxidised dithiolate ligand of the discrete complex 1.

Novel Ni(II) and Zn(II) complexes coordinated by 2-arylaminomethyl-1H-benzimidazole: Molecular structures, spectral, DFT studies and evaluation of biological activity

[NiL1,2Cl2(OH2)3]·zH2O and [ZnL1,2(CH3CO2)2] (L1=(1H-benzimidazol-2-ylmethyl)-N-phenyl amine, z=0 and L2=2-[(1H-Benzimidazol-2-ylmethyl)-amino]-benzoic acid methyl ester, z=1) complexes have been synthesized and characterized by a variety of physico-chemical techniques. The central Ni(II) ion is coordinated by only the pyridine-type nitrogen (Npy) of benzimidazole ring, three water molecules and two chlorido ligands forming a distorted octahedral geometry. Five coordinated zinc complexes were obtained, where the coordination sphere of zinc ion is made up of secondary amino group (NHsec), Npy and two acetate groups, one acts as a unidentate and the other as a bidentate. A theoretical DFT/UB3LYP method combined with LANL2DZ basis set shows that all the metal–ligand bonds are of the L→M type. Electronic structures have been calculated using TD-DFT method. The antibacterial activity of NiL2 complexes decreases by the introduction of COOCH3 group in the ortho-position of the aniline moiety.

A one‐step approach for esterification of zein with methanol

AbstractZein (corn protein) was reacted with methanol in the presence of para‐toluenesulphonic acid under mild conditions to give a material formed by esterification of predominantly the amide groups of the protein. The formation of methyl zeinate was confirmed by proton NMR. The new signal appeared at 3.67 ppm in zein methylation product, which is absent for pure zein can be assigned to the protons of the CH3 group of an ester. The strong CO stretching vibration due to the presence of ester group in the region of 1739 cm−1 in case of methylated zein was also noticed from FTIR studies. The increase in the C : N atom ratio in the zein methylation product obtained from elemental analysis results further indicates the conversion of a significant proportion of the CONH2 groups in zein to COOCH3 groups in the esterified product. The methylated product had glass transition temperature about 20°C lower than that of the unmodified zein. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Method to Synthesize Silver Nano-particles for Inkjet Inks to Reduce Environmental Load

We have been studying the method to prepare metal nano-particles in aqueous solution. We presented the role of low molecular compounds as a dispersing agent in aqueous solutions to synthesize silver particles at NIP27, last year. At NIP28 of this year, we would like to present the effect of PVA and polyacrylic acid compounds on the growth of silver particles. The PVA used in this experiment are as follows: Saponification ratio is 78.5-99.4 mol% and polymerization degree is 500-2600, where the saponification ratio is defined as the ratio of the number of OH group to total number of OH and COOCH3 groups. The above both factors have affected the growth of silver particles and we have found in a series of our experiments that the PVA with the polymerization degree of 500 and the saponification ratio of 99.4 mol% has produced mono-dispersed silver particles of 10nm in average diameter. Furthermore, we have found that polyacrylic acid compounds as a dispersing agent have resulted in around 5nm in average diameter. Since this method to synthesized silver nano-particles does not use any organic solvents, we can avoid the problem regarding environmental pollution caused by organic fluids.

Absolute configuration of methyl isoeichlerialactone

The title compound, C28H44O4·0.56H2O, is a co-crystal of methyl isoeichlerialactone monohydrate as the major component and methyl isoeichlerialactone as the minor component in a 0.55778 (3):0.44222 (3) ratio. The conformations of both components are identical except for that of the –COOCH3 group of the methyl propanoate side chain on the cyclo­hexane ring which is positionally disordered over two orientations. The mol­ecule of methyl isoeichlerialactone has three fused rings and all rings are trans-fused. The two cyclo­hexane rings are in standard chair conformations and the cyclo­pentane ring adopts an envelope conformation. In the crystal, weak C—H⋯O inter­actions link methyl isoeichlerialactone mol­ecules into screw chains along [010]. The crystal structure is further stabilized by O—H⋯O hydrogen bonds and weak C—H⋯O inter­actions.

Vibrational spectral studies of methyl 3-(4-methoxyphenyl)prop-2-enoate, a new organic non-linear optic crystal

Single crystals of methyl 3-(4-methoxyphenyl)prop-2-enoate were grown by the slow evaporation technique and vibrational spectral analysis was carried out using near-IR Fourier transform Raman and Fourier transform IR spectroscopy. Ab initio quantum computations were also performed at the HF/6–311G (d,p) level to derive the equilibrium geometry, vibrational wavenumbers and intensities and first hyperpolarizability. The large NLO efficiency predicted for the first time in this new class of compounds was confirmed by powder efficiency experiments. Hartree–Fock calculations reveal that the endocyclic angle at the junction of the propeonate group and the phenyl ring is decreased from 120° by 2.5°, whereas the two neighbouring angles around the ring are increased by 2.1° and 1.2°, associated with charge-transfer interaction. Vibrational analysis indicates the lowering of asymmetric stretching modes of Me1 and Me2 due to the electronic effects simultaneously caused by back-donation and induction due to the presence of the oxygen atom. The occurrence of Fermi resonance is also identified. The carbonyl stretching vibrations were lowered owing to conjugation and the hydrogen bonding network inside the crystal. The vibrational spectra confirm that the charge-transfer interaction between the COOCH3 group and phenyl ring through the ethylenic bridge must be responsible for simultaneous IR and Raman activation of C7C18 stretching and ring modes 8 and 19. The large intensity differences observed between the 8a and 8b modes in both the IR and Raman spectra are due to the algebraic difference of the electronic effects of the substitutents. The charge transfer interaction between the COOCH3 group and phenyl ring through the ethylenic bridge resulting in π-electron cloud movement from donor to acceptor can make the molecule highly polarized. Intramolecular charge transfer must be responsible for the NLO activity of MMP. Copyright © 2004 John Wiley & Sons, Ltd.