scholarly journals Study on Soy-Based Adhesives Enhanced by Phenol Formaldehyde Cross-Linker

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 365 ◽  
Author(s):  
Zhigang Wu ◽  
Xuedong Xi ◽  
Hong Lei ◽  
Jiankun Liang ◽  
Jingjing Liao ◽  
...  
Keyword(s):  
13C Nmr ◽  
Soy Protein ◽  
Water Resistance ◽  
Phenol Formaldehyde ◽  
Ionization Mass ◽  
Model Compounds ◽  
Esi Ms ◽  
13C Nuclear Magnetic Resonance ◽  
Ft Ir ◽  
Cross Linker

To find the effects of cross-linker phenol-formaldehyde (PF) resin on the performance of soy-based adhesives, the reaction between model compounds hydroxymethyl phenol (HPF) and glutamic acid were studied in this paper. HPF prepared in laboratory conditions showed higher content of hydroxymethyl groups than normal PF resin, which was proved by the results of Electrospray Ionization Mass Spectrometry (ESI-MS) and 13C Nuclear Magnetic Resonance (13C-NMR). The results of ESI-MS, Fourier transform infrared spectroscopy (FT-IR), and 13C-NMR based on resultant products obtained from model compounds showed better water resistance of the soy protein-based adhesive modified by PF-based resin, which indicated the reaction between PF resin and soy protein. However, it seemed that the soy-based adhesive cross-linked by HPF with the maximum content of hydroxymethyl groups did not show the best water resistance.

scholarly journals A highly sensitive octopus-like azobenzene fluorescent probe for determination of abamectin B1 in apples

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhenlong Guo ◽  
YiFei Su ◽  
Kexin Li ◽  
MengYi Tang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Ionization Mass ◽  
Limit Of Quantification ◽  
Visible Absorption ◽  
Esi Ms ◽  
Relative Standard ◽  
Ft Ir

AbstractThe development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5′-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule has been characterized by ultraviolet–visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectra. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L−1 and 4.4 μg L−1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was present based on relative standard deviation of 2.2%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe demonstrated reasonable sensitivity, specificity and selectivity. The results indicate that the octopus-like azobenzene fluorescent probe can be expected to be reliable for evaluating abamectin B1 in agricultural foods.

Synthesis and characterization of carbonate-encapsulated ytterbium- and yttrium-containing polyoxotungstates

2018 ◽  
Vol 74 (11) ◽  
pp. 1355-1361 ◽  
Author(s):  
Reetam Kaushik ◽  
Imran Khan ◽  
Mukesh Kumar Saini ◽  
Firasat Hussain ◽  
Masahiro Sadakane
Keyword(s):  
Sodium Salt ◽  
Lone Pair ◽  
Analytical Techniques ◽  
Lanthanide Ions ◽  
Ionization Mass ◽  
Sodium Acetate Solution ◽  
Acetate Solution ◽  
Esi Ms ◽  
Sandwich Type ◽  
Ft Ir

A sandwiched-type carbonate-encapsulated yttrium-containing arsenotungstate(III) has been synthesized under mild reaction conditions. The polyanion [NaCH3COO{Y2(H2O)3(B-α-AsW9O33)2(W2O5)(CO3)}]12− (1) was isolated as a solid crystalline material by the reaction of a YIII salt with the sodium salt of trilacunary [AsW9O33]9− in sodium acetate solution. The sodium salt of the polyanion, i.e. Na12[Na(CH3COO){Y2(AsW9O33)2(W2O5)(CO3)(H3O)3}]·22H2O (1a), was characterized by various analytical techniques, such as FT–IR, single-crystal X-ray diffraction (SC–XRD), TGA (thermogravimetric analysis), 13C NMR and ESI–MS (electrospray ionization mass spectrometry). SC–XRD studies revealed that the polyanion crystallizes in the triclinic space group P\overline{1}. The structure showed that the polyanion is a carbonate-encapsulated sandwich-type species, consisting of two trilacunary B-α-[AsW9O33]9−, with a lone-pair-containing AsIII heteroatom, together with two extra tungsten centres and two yttrium cations at the sandwich position, where CH3COO− and Na+ ions act as linkers between the two polyanion units. In addition, we have also synthesized two carbonate-encapsulated germanotungstates(IV), without lone-pair-containing heteroatoms, with the formula [Ln3(A-β-GeW9O34)2(CO3)(H2O)3]13− [Ln = YIII (2) and YbIII (3)], i.e. Y2K3Na4[Y3(A-β-GeW9O34)2(CO3)(H2O)3]·19H2O (2a) and YbK8Na2[Yb(A-β-GeW9O34)2(CO3)(H2O)3]·16H2O (3a), and characterized them by FT–IR, SC–XRD, TGA and ESI–MS. Here, the lanthanide ions act as linkers, extending the structures into higher dimensions. Sodium and potassium ions also play a key role as linkers, further extending the structure. The packing shows the presence of certain hydrophilic pores within the structure.

A highly sensitive octopus-like azobenzene fluorescent probe for determination of abamectin B1 in apples

2020 ◽  
Author(s):  
Zhenlong Guo ◽  
YiFei Su ◽  
Kexin Li ◽  
MengYi Tang ◽  
Qiang Li ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Limit Of Detection ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Ionization Mass ◽  
Limit Of Quantification ◽  
Visible Absorption ◽  
Esi Ms ◽  
Relative Standard ◽  
Ft Ir

Abstract The development of detecting residual level of abamectin B1 in apples is of great importance to public health. Herein, we synthesized a octopus-like azobenzene fluorescent probe 1,3,5-tris (5'-[(E)-(p-phenoxyazo) diazenyl)] benzene-1,3-dicarboxylic acid) benzene (TPB) for preliminary detection of abamectin B1 in apples. The TPB molecule was characterized by ultraviolet-visible absorption spectrometry, 1H-nuclear magnetic resonance, fourier-transform infrared (FT-IR), electrospray ionization mass spectroscopy (ESI-MS) and fluorescent spectrum. A proper determination condition was optimized, with limit of detection and limit of quantification of 1.3 µg L-1 and 4.4 μg L-1, respectively. The mechanism of this probe to identify abamectin B1 was illustrated in terms of undergoing aromatic nucleophilic substitution, by comparing fluorescence changes, FT-IR and ESI-MS. Furthermore, a facile quantitative detection of the residual abamectin B1 in apples was achieved. Good reproducibility was shown based on relative standard deviation of 2.20%. Six carboxyl recognition sites, three azo groups and unique fluorescence signal towards abamectin B1 of this fluorescent probe decided ideal sensitivity, specificity and selectivity. The results show that the octopus-like azobenzene fluorescent probe may be promising for evaluating abamectin B1 in agricultural foods.

scholarly journals 4,6-Dinitro-7-(thiazol-2-ylamino)benzo[c][1,2,5]oxadiazole 1-oxide

Molbank ◽  
10.3390/m1165 ◽  
2020 ◽  
Vol 2020 (4) ◽  
pp. M1165
Author(s):  
Gabriele Micheletti ◽  
Dario Telese ◽  
Carla Boga
Keyword(s):  
1H Nmr ◽  
13C Nmr ◽  
Esi Ms ◽  
Snar Reaction ◽  
Ft Ir

4,6-Dinitro-7-(thiazol-2-ylamino)benzo[c][1,2,5]oxadiazole 1-oxide was synthesized by a SNAr reaction between 7-chloro-4,6-dinitrobenzofuroxan and 2-aminothiazole. The structure of the newly synthesized compound (45% yield) was elucidated based on 1H-NMR, 13C-NMR, NOESY-1D, ESI-MS, UV-Vis, and FT-IR techniques.

1H, 13C NMR, FT-IR, ESI MS and PM5 studies of a new 3,6,9-trioxadecylamide of monensin A and its complexes with Li+, Na+ and K+ cations

2011 ◽  
Vol 990 (1-3) ◽  
pp. 121-131 ◽  
Author(s):  
Daniel Łowicki ◽  
Adam Huczyński ◽  
Bogumil Brzezinski ◽  
Franz Bartl
Keyword(s):  
13C Nmr ◽  
Esi Ms ◽  
Ft Ir ◽  
Monensin A

scholarly journals Structural Characterization of Cure Bio-based Phenol Formaldehyde Wood Adhesive

2020 ◽  
pp. 12-19
Author(s):  
Y. B. Olayiwola
Keyword(s):  
13C Nmr ◽  
Liquid State ◽  
Phenol Formaldehyde ◽  
Wood Adhesive ◽  
Resin System ◽  
Nmr Study ◽  
13C Nmr Analysis ◽  
13C Nuclear Magnetic Resonance ◽  
Phenolic Components

Bio-phenol formaldehyde (BPF) resole resins were characterized by liquid-state 13C Nuclear Magnetic Resonance (NMR) spectroscopy. The liquid 13C NMR analysis indicated that the condensation reactions between the bark phenolic compounds and the formaldehyde occurred during the synthesis of the resins. Methylene ether bridges in the resins were more pronounced in the BPF resin when compared to the PF resin system. The liquid-state 13C NMR study revealed significant differences in the resins structures induced by the inclusion of bark-phenolic components. The bark-phenolic components favored the formation of para-ortho methylene linkages in the BPF resins and also enhanced the cure rate of the BPF resin system.

Sign in / Sign up

Export Citation Format

Share Document