scholarly journals Preparation of Glucosamine Hydrochloride from Indigenous Shrimp Processing Waste

1970 ◽  
Vol 46 (3) ◽  
pp. 375-378 ◽  
Author(s):  
MM Islam ◽  
SM Masum ◽  
MM Rahman ◽  
AA Shaikh
Keyword(s):  
Maximum Yield ◽  
Therapeutic Activity ◽  
Processing Waste ◽  
Reaction Conditions ◽  
Glucosamine Hydrochloride ◽  
Glycoside Linkage ◽  
Shrimp Shell ◽  
Reaction Proceeds ◽  
Ft Ir ◽  
Hydrolysis Of

The present investigation described the effective preparation of glucosamine hydrochloride (GluHCl) from chitin which was extracted from indigenous shrimp shell. GluHCl has attracted much attention owing to its therapeutic activity in osteoarthritis and widely used dietary supplement. The key step involved was extraction of chitin from shrimp skeleton and then hydrolysis of chitin by concentrated hydrochloric acid. The reaction proceeds via break down of glycoside linkage. Structural analysis was carried out by melting point, TLC, FT-IR, elemental analysis and all the data were compared with that of standard GluHCl. The elemental (C, 32.75; H, 6.51; N, 6.20) analysis is good concord with the calculated value (C, 33.42; H, 6.54; N, 6.50). Absence of v max at 1726 cm-1 indicates that GluHCl is a deacetylated product of chitin. The yields of the product mainly depend on reaction conditions. Maximum yield (63.5%) was obtained when chitin was hydrolyzed with concentrated HCl for 1.30 h. Key words: Shrimp shell; Chitin, Acid hydrolysis; Glucosamine hydrochloride Osteoarthritis. DOI: http://dx.doi.org/10.3329/bjsir.v46i3.9046 BJSIR 2011; 46(3): 375-378

Free chymotrypsin-catalyzed synthesis of peptide bond in aliphatic alcohols with low water content

1989 ◽  
Vol 54 (1) ◽  
pp. 266-276 ◽  
Author(s):  
Václav Čeřovský ◽  
Karel Martinek
Keyword(s):  
Dimethyl Sulfoxide ◽  
Water Content ◽  
Maximum Yield ◽  
Peptide Bond ◽  
Aliphatic Alcohols ◽  
Amino Terminal ◽  
Effect Of Water ◽  
Reaction Proceeds ◽  
Hydrolysis Of ◽  
Lower Water Content

The effect of water content on free chymotrypsin-catalyzed reaction of Ac-Tyr-OEt with HBr.Gly-NH2 in triethylamine-containing 2-propanol was studied. Maximum yield of dipeptide Ac-Tyr-Gly-NH2 was obtained in 2-propanol with 2% of water. Lower water content retards the reaction. Although higher water content accellerates the process, the yield of the dipeptide is reduced by enzymatically catalyzed hydrolysis of Ac-Tyr-OEt. The studied reaction proceeds analogously also in other aliphatic alcohols woth low content of water except in methanol; it does not take place in dimethylformamide or dimethyl sulfoxide containing 2% or 20% of water. In 2-propanol with 2% or 5% of water, syntheses of the protected amino-terminal oxytocine and vasopressin tripeptide, as well as other model peptides, were studied. In all the described experiments, α-chymotrypsin without any stabilization or immobilization was employed.

scholarly journals Selective Nitration of Chlorobenzene by NO2 in the Alkali Zeolite NaZSM-5

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Scott J. Kirkby
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Temperature Dependent ◽  
Reaction Conditions ◽  
Cation Site ◽  
Zeolite Lattice ◽  
Reaction Proceeds ◽  
Ft Ir ◽  
Electron Donation

Chlorobenzene was reacted with NO2, in the initially acid-free zeolite NaZSM-5, to yield para-chloronitrobenzene exclusively. The precursors were loaded sequentially into self-supporting pellets of the zeolite, contained within a stainless steel cell, from the gas phase. The reaction proceeds spontaneously at room temperature. It is, however, very temperature dependent and effectively ceases at zero degrees Celsius. The reaction was monitored in situ using FT-IR. The active nitrating agent is formed from the partial electron donation by the NO2 to the Na+ cations present in the zeolite lattice. Under the reaction conditions, chlorobenzene is not readily mobile through the pore system; thus, only the molecules adsorbed near a cation site react to form para-chloronitrobenzene.

scholarly journals Synthesis of poly(γ-tert-butyl L-glutamate): influence of polymerization conditions

2019 ◽  
Vol 16 (3) ◽  
pp. 25
Author(s):  
Phung Thi Thuy Dung ◽  
Nguyen Thi Le Thu
Keyword(s):  
Ring Opening ◽  
Gel Permeation Chromatography ◽  
Attenuated Total Reflection ◽  
Resonance Spectroscopy ◽  
Reaction Conditions ◽  
Tert Butyl ◽  
Ft Ir ◽  
Hydrolysis Of ◽  
Polymerization Conditions

This work presents the synthesis and characterization of poly(γ-tert-butyl L-glutamate) (PtBuLG) via a living ring-opening polymerization procedure of γ-tert-butyl L-glutamate N-carboxyanhydride (tBuLG-NCA). The reaction conditions were investigated to optimize the polymerization yield and molecular weight polydispersity. The synthesized PtBuLG was characterized using nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC) and attenuated total reflection-Fourier transform infrared (ATR FT-IR. Finally, hydrolysis of PtBuLG resulted in poly(L-glutamic acid) (PLGA).

Effect of Fenton pretreatment on enzymatic hydrolysis of poplar

BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1980-1987
Author(s):  
Shujie Wang ◽  
Jin Sun ◽  
Mengjie Chen ◽  
Xianfeng Hou ◽  
Zhenzhong Gao
Keyword(s):  
Enzymatic Hydrolysis ◽  
Maximum Yield ◽  
Amorphous Region ◽  
Xrd Analysis ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
Fast Reaction ◽  
Fenton Reagents ◽  
Ft Ir ◽  
Hydrolysis Of

The Fenton reaction has been widely used in the pretreatment of lignocellulose. It offers the advantages of simple operation, fast reaction speed, and low pollution. In this study, the effects of different proportions of Fenton reagents on the enzymatic hydrolysis of poplar were compared and analyzed, and the optimal ratio of Fenton reagents was obtained. The maximum yield of enzymatic hydrolysis of glucose in Fenton pretreatment samples was 406 mg/g at H2O2 and Fe2+ concentrations of 1.0 mol/L and 0.01 mol/L, respectively, which was 2.5 times that of untreated samples. Meanwhile, the composition analysis and FT-IR analysis showed that Fenton pretreatment could degrade lignin and hemicellulose effectively. X-ray diffraction (XRD) analysis showed that Fenton pretreatment can partially destroy the amorphous region of poplar. These findings will contribute to efforts to improve the viability of the Fenton pretreatment process for converting biomass into energy.

The Preparation of Micro-Molecular Dextran in Sub-Critical Water/CO2

2013 ◽  
Vol 712-715 ◽  
pp. 502-505
Author(s):  
Shu Qiong Liao ◽  
Xiao Yu Peng ◽  
Xue Wang Zhang ◽  
Ke Lin Huang ◽  
Ben Wang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Temperature Reaction ◽  
Liquid Ratio ◽  
Reaction Conditions ◽  
Reaction Pressure ◽  
Optimum Reaction ◽  
Ft Ir ◽  
Solid Liquid ◽  
Hydrolysis Of

Micro-molecular dextran was prepared in sub-critical water/CO2 by hydrolysis of dextran20. The obtained products were mainly characterized by FT-IR and GPC. Furthermore, the reaction temperature, reaction time, reaction pressure, solid-liquid radio and stirring speed were systematically investigated during the work. The optimum reaction conditions are as follows: the reaction temperature was 160°C; the reaction time was 60 min; the reaction pressure was 2.5MPa; the solid-liquid ratio was 0.6 and the stirring speed was 300r/min.

Solid State Analysis and Theoretical Explorations on Polymorphic and Hydrate Forms of p-Hydroxybenzaldehyde Isonicotinichydrazone: Effect of Additives on Polymorphic Crystallization

2018 ◽  
Author(s):  
Lincy Tom ◽  
Victoria A. Smolenski ◽  
Jerry P. Jasinski ◽  
M.R. Prathapachandra Kurup
Keyword(s):  
Hirshfeld Surface ◽  
Framework Analysis ◽  
Reaction Conditions ◽  
Space Groups ◽  
Effect Of Additives ◽  
Ft Ir ◽  
Packing Arrangement ◽  
The Stability ◽  
Ir And Raman ◽  
Isonicotinic Hydrazide

The reaction of p-hydroxybenzaldehyde with an equimolar amount of isonicotinic hydrazide afforded two polymorphic and hydrate forms of p-hydroxybenzaldehyde isonicotinichydrazone (HBIH) by varying the experimental reaction conditions. The compounds are fully characterized by means of single crystal and powder diffraction methods, vibrational spectroscopy (FT-IR and Raman), thermal and elemental analysis. The compound crystallizes in three different forms in two different space groups, P21/c (form PA and PB) and Pbca (PC). The Hirshfeld surface analysis shows the differences in the relative contributions of intermolecular interactions to the total Hirshfeld surface area for the HBIH molecules. The calculated pairwise interaction energies (104-116 kJ/mol) can be related to the stability of the crystals. Energy framework analysis identifies the interaction hierarchy and their topology. The geometry and conformation of the three forms are essentially similar which differ only by packing arrangement.

Solid State Analysis and Theoretical Explorations on Polymorphic and Hydrate Forms of p-Hydroxybenzaldehyde Isonicotinichydrazone: Effect of Additives on Polymorphic Crystallization

2018 ◽  
Author(s):  
Lincy Tom ◽  
Victoria A. Smolenski ◽  
Jerry P. Jasinski ◽  
M.R. Prathapachandra Kurup
Keyword(s):  
Hirshfeld Surface ◽  
Framework Analysis ◽  
Reaction Conditions ◽  
Space Groups ◽  
Effect Of Additives ◽  
Ft Ir ◽  
Packing Arrangement ◽  
The Stability ◽  
Ir And Raman ◽  
Isonicotinic Hydrazide

The reaction of p-hydroxybenzaldehyde with an equimolar amount of isonicotinic hydrazide afforded two polymorphic and hydrate forms of p-hydroxybenzaldehyde isonicotinichydrazone (HBIH) by varying the experimental reaction conditions. The compounds are fully characterized by means of single crystal and powder diffraction methods, vibrational spectroscopy (FT-IR and Raman), thermal and elemental analysis. The compound crystallizes in three different forms in two different space groups, P21/c (form PA and PB) and Pbca (PC). The Hirshfeld surface analysis shows the differences in the relative contributions of intermolecular interactions to the total Hirshfeld surface area for the HBIH molecules. The calculated pairwise interaction energies (104-116 kJ/mol) can be related to the stability of the crystals. Energy framework analysis identifies the interaction hierarchy and their topology. The geometry and conformation of the three forms are essentially similar which differ only by packing arrangement.

Synthesis and Evaluation of Levulinic Ester as Biodiesel Additives

2020 ◽  
Vol 71 (8) ◽  
pp. 21-26
Author(s):  
Elena-Emilia Oprescu ◽  
Cristina-Emanuela Enascuta ◽  
Elena Radu ◽  
Vasile Lavric
Keyword(s):  
Maximum Yield ◽  
Strength Distribution ◽  
Point Of View ◽  
Reaction Parameters ◽  
X Ray ◽  
Ethyl Levulinate ◽  
Ft Ir ◽  
Ir Analysis ◽  
Biodiesel Blend ◽  
Acid Strength Distribution

In this study, the SO42-/TiO2-La2O3-Fe2O3 catalyst was prepared and tested in the conversion of fructose to ethyl levulinate . The catalyst was characterized from the point of view of the textural analysis, FT-IR analysis, acid strength distribution, X-ray powder diffraction and pyridine adsorption IR spectra. The influence of the reaction parameters on the ethyl levulinate yield was study. The maximum yield of 37.95% in levulinate esters was obtained at 180 �C, 2 g catalyst and 4 h reaction time. The effect of ethyl levulinate addition to diesel-biodiesel blend in different rates, i.e, 0.5, 1, 2.5, 5 (w.t %) on density, kinematic viscosity and flash point was evaluated and compared with the European specification.

Process intensification for enzyme assisted turmeric starch hydrolysis in hydrotropic and supercritical conditions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yogita P. Labrath ◽  
Prafulla V. Belge ◽  
Uma G. Kulkarni ◽  
Vilas G. Gaikar
Keyword(s):  
Residence Time ◽  
Filtration Rate ◽  
Room Temperature ◽  
Curcuma Longa ◽  
Process Intensification ◽  
Enzyme Treatment ◽  
Starch Hydrolysis ◽  
Reaction Conditions ◽  
Natural Form ◽  
Hydrolysis Of

Abstract The turmeric rhizome (Curcuma longa) contains curcuminoids embedded in the starch matrix. It is thus important to target starch hydrolysis to enhance extraction of curcuminoids. In the case of starch hydrolysis, α-amylase is more efficient when the starch is in a gelatinised form than when it is in its natural form. The present work includes hydrolysis of turmeric starch in its natural and gelatinised forms using α-amylase in hydrotrope solution (HS) and scCO2. The optimum rate of starch hydrolysis was obtained using 200 IU cm−3 of α-amylase, at reaction conditions of 6.5 pH at 328 K when 10% w/w of turmeric powder was stirred at 900 rpm in HSs. The hydrolysis in 15 MPa scCO2 at room temperature required a phase modifier and 40 min of residence time (RT). The enzyme treatment of turmeric powder in HSs increased the filtration rate for curcuminoid extraction (gelatinised and native) compared to untreated turmeric powder.

scholarly journals Synthesis and Structural Characterization of (E)-4-[(2-Hydroxy-3-methoxybenzylidene)amino]butanoic Acid and Its Novel Cu(II) Complex

Molbank ◽  
10.3390/m1179 ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. M1179
Author(s):  
Eleftherios Halevas ◽  
Antonios Hatzidimitriou ◽  
Barbara Mavroidi ◽  
Marina Sagnou ◽  
Maria Pelecanou ◽  
...  
Keyword(s):  
Schiff Base ◽  
Gamma Aminobutyric Acid ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Polymeric Compound ◽  
Bridging Ligands ◽  
1H And 13C Nmr ◽  
One Dimensional ◽  
Ft Ir

A novel Cu(II) complex based on the Schiff base obtained by the condensation of ortho-vanillin with gamma-aminobutyric acid was synthesized. The compounds are physico-chemically characterized by elemental analysis, HR-ESI-MS, FT-IR, and UV-Vis. The complex and the Schiff base ligand are further structurally identified by single crystal X-ray diffraction and 1H and 13C-NMR, respectively. The results suggest that the Schiff base are synthesized in excellent yield under mild reaction conditions in the presence of glacial acetic acid and the crystal structure of its Cu(II) complex reflects an one-dimensional polymeric compound. The molecular structure of the complex consists of a Cu(II) ion bound to two singly deprotonated Schiff base bridging ligands that form a CuN2O4 chelation environment, and a coordination sphere with a disordered octahedral geometry.

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