Comparison between Conventional and Ultrasonic Preparation of Chitosan from Shrimp Shells Waste

2015 ◽  
Vol 1123 ◽  
pp. 205-208
Author(s):  
Zainal Arifin ◽  
D. Irawan
Keyword(s):  
Reaction Time ◽  
Sodium Hydroxide ◽  
Ultrasonic Irradiation ◽  
Ultrasound Irradiation ◽  
Promising Alternative ◽  
Acidic Solutions ◽  
Degree Of Deacetylation ◽  
Shrimp Shells ◽  
Ultrasonic Preparation ◽  
Enzymatic Methods

Chitosan is a natural biopolymer derived by deacetylation of chitin from the two main sources of crustaceans, shrimp and crabs. Chitosan, which is soluble in acidic solutions, is used in many applications (biomedical/pharmaceutical, water engineering, food, cosmetics). There have been many researchers who have developed a process of deacetylation of chitin from shrimp shells waste by thermochemical or enzymatic methods. However, application of ultrasonic irradiation for chitin deacetylation has received little attention. In this work, the deacetylation of chitin with concentrated sodium hydroxide was performed using ultrasound irradiation (80 W, 42 kHz). The reaction time and degree of deacetylation were compared with conventional process. Results showed that under the same condition, the degree of deacetylation was similar. However, the use of ultrasonic irradiation decreased the reaction time, showing that this method may be a promising alternative method to the conventional method.

Synthesis of Ropivacaine under Ultrasound Irradiation

2013 ◽  
Vol 634-638 ◽  
pp. 1152-1156
Author(s):  
Sai Li ◽  
Xiao Bin Fu ◽  
Li Liu ◽  
Nuo Lan ◽  
Weng Qi Meng ◽  
...  
Keyword(s):  
Reaction Time ◽  
Ultrasonic Irradiation ◽  
Total Yield ◽  
Ultrasound Irradiation ◽  
Pipecolic Acid ◽  
Successive Reaction ◽  
Present Procedure ◽  
Conventional Methods ◽  
Ropivacaine Hydrochloride

Ropivacaine hydrochloride was synthesized from 2-pipecolic acid by successive reaction with SOCl2 and 2,6-dimethylaniline at 40°C under ultrasonic irradiation to give (S)-N-(2,6-dimethylphenyl)-piperidin-2-carboxamide (4), and 4 was reacted with 1-bromopropane at 50°C for 1 h under ultrasonic irradiation. The effect of reaction solvent, temperature and time under ultrasonic irradiation were investigated. Compared with conventional methods, the main advantages of the present procedure are milder conditions, shorter reaction time and higher yields. The total yield was 63.1%, [α]25 D= – 6.7°(c = 2, H2O).

scholarly journals Chemical modification of alginic acid by ultrasonic irradiation

2016 ◽  
Vol 3 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Dilyana Murdzheva ◽  
Panteley Denev
Keyword(s):  
Reaction Time ◽  
Chemical Modification ◽  
Ultrasonic Irradiation ◽  
Alginic Acid ◽  
Ultrasound Irradiation ◽  
Ultrasonic Frequency ◽  
Degree Of Esterification ◽  
Reaction Efficiency ◽  
Modification Process ◽  
Ft Spectroscopy

Abstract: Chemical modification of alginic acid has been done by ultrasonic irradiation to obtain its methylated, ethylated and isopropylated derivatives. The influence of ultrasonic frequency and power on esterification process of alginic acid has been investigated. Alginate derivatives have been characterized by degree of esterification (DE) and IR-FT spectroscopy. It has been found that 45 kHz ultrasonic frequency accelerated modification process as reduced the reaction time from 16 hours to 2 hours. The obtained results showed that ultrasound irradiation increased the reaction efficiency in methanol and depended on the ratio of the M/G.

Continuous precipitation of monodispersed yttrium basic carbonate powders: Part III. Kinetics

1992 ◽  
Vol 7 (8) ◽  
pp. 2269-2272 ◽  
Author(s):  
Y-S. Her ◽  
E. Matijević ◽  
W.R. Wilcox
Keyword(s):  
Experimental Data ◽  
Reaction Time ◽  
Linear Function ◽  
Model Equation ◽  
Conversion Yield ◽  
Continuous Precipitation ◽  
Empirical Constant ◽  
Continuous Processes ◽  
Acidic Solutions ◽  
Basic Carbonate

The reaction kinetics involved in the continuous precipitation of monodispersed spherical yttrium basic carbonate particles was studied. The amount of powder produced was a linear function of H2CO3 generated by the decomposition of urea in mildly acidic solutions. A model equation, containing an empirical constant F, was derived to describe the conversion yield as a function of reactant concentrations, reaction time, and temperature. The calculated and experimental data agree well for both the batch and continuous processes.

Catalyst-free, one-pot, four-component green synthesis of functionalized 1-(2-fluorophenyl)-1,4-dihydropyridines under ultrasound irradiation

2016 ◽  
Vol 40 (6) ◽  
pp. 5107-5112 ◽  
Author(s):  
Nhlanhla Shabalala ◽  
Suresh Maddila ◽  
Sreekantha B. Jonnalagadda
Keyword(s):  
Green Synthesis ◽  
Ultrasonic Irradiation ◽  
Aqueous Ethanol ◽  
Ultrasound Irradiation ◽  
One Pot ◽  
Catalyst Free ◽  
New Compounds ◽  
Synthesis Protocol

A catalyst-free synthesis protocol for functionalized 1,4-dihydropyridines under ultrasonic irradiation in aqueous ethanol is reported with excellent yields. Eleven new compounds are synthesized using dimethylacetylenedicarboxylate, 2-fluoroaniline, malononitrile and various substituted aldehydes.

scholarly journals One pot synthesis of 3, 4-dihydropyrimidine-2(1H)-thiones using orange peel powder under ultrasonic irradiation

2020 ◽  
Vol 9 (1) ◽  
pp. 919-923
Keyword(s):  
Reaction Time ◽  
Ultrasonic Irradiation ◽  
Heterocyclic Compounds ◽  
Multicomponent Reactions ◽  
Orange Peel ◽  
Biologically Active ◽  
High Yield ◽  
Atom Economy ◽  
One Pot ◽  
The Past

Biginelli, an important multicomponent reaction provides an avenue for the synthesis of different biologically active heterocyclic compounds. During the past decade, one pot multicomponent reactions have attracted the attention of organic and medicinal chemists due to high atom economy, time and enery saving convergent nature. The present manuscript reports a simple one pot three component synthesis of 3, 4-dihydroprimidin-2(1H)-thiones from various diversely substituted aldehydes, ethyl acetoacetate and thiourea using a orange peel powder as a natural catalyst on ultrasonic irradiation in aqueous medium as the solvent. The advantages of this reaction are less reaction time, high yield, easy availability of the catalyst and green nature.

scholarly journals Central Composite Design and Desirability of RSM for Optimization of Biodiesel Production from Mixture of Animal Waste Fat Oil and used Cooking Oil

2020 ◽  
Vol 9 (4) ◽  
pp. 1565-1571
Keyword(s):  
Reaction Time ◽  
Sodium Hydroxide ◽  
Maximum Yield ◽  
Animal Waste ◽  
Sodium Hydroxide Concentration ◽  
Used Cooking Oil ◽  
Input Parameters ◽  
Desirability Approach ◽  
Central Composite ◽  
Waste Fat

In this work, central composite design(CCD) and desirability approach of Response surface methodology (RSM) has been used for optimization of biodiesel yield produced from mixture of animal waste fat oil and used cooking oil (AWO) in the ratio of 1:1through alkaline transesterification process. In this work, methanol quantity, reaction time and sodium hydroxide concentration are selected as input parameters and yield selected as response. The combined effect of methanol quantity, reaction time and sodium hydroxide concentration were investigated and optimized by using RSM. The second order model is generated to predict yield as a function of methanol quantity, reaction time and sodium hydroxide concentration. A statistical model predicted the maximum yield of 96.9779% at 35ml methanol quantity (% v/v of oil), 75 min. reaction time and 0.6g (% wt./v of oil) of sodium hydroxide. Experimentally, the maximum yield of 97% was obtained at the above optimized input parameters. The variation of 0.02% was observed between experimental and predicted values. In this work, an attempt has also made to use desirability approach of RSM to optimize the input parameters to predict maximum yield. Desirability approach predicts maximum yield (97.075%) at CH3OH (35.832% vol. /vol. of oil), NaOH (0.604 % wt./vol. of oil) and reaction time (79.054min.) was found for the AWO.

Synthetic Technology and Performance of a Novel Fatty Alcohol Polyoxyethylene Carboxylate Surfactants

2011 ◽  
Vol 298 ◽  
pp. 163-168 ◽  
Author(s):  
Yuan Yuan Lei ◽  
Guo Zheng ◽  
Yu Sun ◽  
Yong Zhou
Keyword(s):  
Reaction Time ◽  
Optimum Condition ◽  
Sodium Hydroxide ◽  
Fatty Alcohol ◽  
Succinic Anhydride ◽  
Foam Stability ◽  
Raw Materials ◽  
Molar Ratio ◽  
New Type ◽  
And Performance

In this paper, with fatty alcohol polyoxyethylene (AEO9), succinic anhydride (SA) and sodium hydroxide as raw materials, a new type of fatty alcohol polyoxyethylene carboxylate surfactants (SAE9C-Na) was obtained by esterification and neutralizing effect. The influencing factors were researched and its surface properties were studied. The optimum condition of synthesis was determined: molar ratio of alcohol to acid was 1:1.1, reaction temperature was 85°C, reaction time was 60 min, under this condition, the yield could reach up to 95.8%. The results received from this experiment showed that SAE9C-Na had excellent surface activity and foaming and foam stability, whose emulsification and solubility enhancement were improved greatly.

Biodiesel Production From Crude Rubber Seed Oil Using Supercritical Methanol Transesterification

2015 ◽  
Vol 781 ◽  
pp. 655-658 ◽  
Author(s):  
Thakun Sawiwat ◽  
Somjai Kajorncheappunngam
Keyword(s):  
Reaction Time ◽  
Seed Oil ◽  
Raw Material ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Supercritical Methanol ◽  
Rubber Seed Oil ◽  
Promising Alternative ◽  
Rubber Seed ◽  
Biodiesel Synthesis

Synthesis of biodiesel from rubber seed oil using a supercritical methanol was investigated under various reaction conditions (220 - 300°C, 80 - 180 bar) with reaction time of 1-15 min and oil:methanol molar ratio of 1:20 - 1:60. Free fatty acid methyl esters (FAMEs) content were analyzed by gas chromatography-mass spectroscopy (GC-MS). Most properties of produced biodiesel were in good agreement with biodiesel standard (EN 14214). The maximum FAME yield of 86.90% was obtained at 260°C, 160 bar, 5 min reaction time using oil:methanol molar ratio of 1:40. The result showed the acid value of rubber seed oil decreased to 0.58 mgKOH/g from initial 24 mgKOH/g to. It could be concluded from this findings that crude rubber seed oil is a promising alternative raw material for biodiesel synthesis via supercritical methanol tranesterification.

scholarly journals Physicochemical and Antibacterial Properties of Chitosan Extracted from Waste Shrimp Shells

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
José Carlos Vilar Junior ◽  
Daylin Rubio Ribeaux ◽  
Carlos Alberto Alves da Silva ◽  
Galba Maria De Campos-Takaki
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Properties ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Degree Of Deacetylation ◽  
Shrimp Shells ◽  
Shrimp Shell ◽  
Ft Ir ◽  
High Degree

This research aims to study the production of chitosan from shrimp shell (Litopenaeus vannamei) of waste origin using two chemical methodologies involving demineralization, deproteinization, and the degree of deacetylation. The evaluation of the quality of chitosan from waste shrimp shells includes parameters for the yield, physical chemistry characteristics by infrared spectroscopy (FT-IR), the degree of deacetylation, and antibacterial activity. The results showed (by Method 1) extraction yields for chitin of 33% and for chitosan of 49% and a 76% degree of deacetylation. Chitosan obtained by Method 2 was more efficient: chitin (36%) and chitosan (63%), with a high degree of deacetylation (81.7%). The antibacterial activity was tested against Gram-negative bacteria (Stenotrophomonas maltophiliaandEnterobacter cloacae) and Gram-positiveBacillus subtilisand the Minimum Inhibitory Concentrations (MIC) and the Minimum Bactericidal Concentration (MBC) were determined. Method 2 showed that extracted chitosan has good antimicrobial potential against Gram-positive and Gram-negative bacteria and that the process is viable.

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