scholarly journals Optimization of Formic Acid/Acetic Acid for Lignin Extraction in Talahib (Saccharum spontaneum L.) and the Analysis of the Adsorbent Properties of Lignin Towards Cu(II) and Pb(II) in Aqueous Solution

KIMIKA ◽  
2021 ◽  
Vol 32 (1) ◽  
pp. 46-57
Author(s):  
Ma. Rickamae Datiles ◽  
Kevinilo Marquez
Keyword(s):  
Acetic Acid ◽  
Reaction Time ◽  
Formic Acid ◽  
Substrate Uptake ◽  
Saccharum Spontaneum ◽  
Spectroscopy Analysis ◽  
Lignin Extraction ◽  
Adsorption Processes ◽  
Pseudo Second Order ◽  
Acetic Acid Water

In this paper, Talahib (Saccharum spontaneum L), was subjected to lignin extraction using Formic Acid/Acetic Acid Pulping. The effect of the formic acid/acetic acid/water ratio and the reaction time to the lignin yield was determined. It was found that increasing the concentration of formic acid decreased the lignin yield due to the formation of formate esters, which in turn decreased its reactivity to condense with other materials in the solution. In terms of reaction time, highest yield was observed at lowest cooking time due to the absence of recondensation reactions. Then, the pulp was subjected to further delignification using peroxyacid treatment, which aided in the isolation of any residual lignin left. The isolated lignin was characterized using UV-Vis and ATR-FTIR spectroscopy. Analysis of the adsorbent capability of lignin towards Cu(II) and Pb(II) showed % equilibrium removal amounts of 14.149 ± 0.227 % and 11.384 ± 0.572 %, respectively, both with an equilibrium contact time of 20 minutes. Through kinetic analysis, it was observed that both adsorption processes follow a pseudo-second order model, which means that the adsorption rate depends on the concentrations of both the metal cation and the lignin adsorbent. It also showed that the substrate uptake was greater with Cu(II) (0.330 ± 0.0082 mg/g lignin) compared to Pb(II) (0.262 ± 0.0159 mg/g lignin).    

Suzuki–Miyaura Cross-Couplings under Acidic Conditions

Synthesis ◽  
2019 ◽  
Vol 52 (06) ◽  
pp. 882-892
Author(s):  
Lucas Pruschinski ◽  
Ana-Luiza Lücke ◽  
Tyll Freese ◽  
Sean-Ray Kahnert ◽  
Sebastian Mummel ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Reaction Time ◽  
Sodium Carbonate ◽  
Acid Water ◽  
Reaction Parameters ◽  
Acid Base ◽  
Acetic Acid Water ◽  
Acidic Conditions ◽  
Carbonate Reaction

Suzuki–Miyaura reactions with Pd(PPh3)4 have been carried out using lithium N-phenylsydnone-4-carboxylate as additive, which gave best yields at pH 5.7 in a mixture of acetic acid, water, and sodium carbonate. Reaction parameters such as the Pd source, the solvent, reaction time and temperature, acid, base and carboxylate have been varied and some representative examples of the Suzuki–Miyaura reaction have been examined.

scholarly journals Comparison of various organic acids for xylo-oligosaccharide productions in terms of pKa values and combined severity

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Rou Cao ◽  
Xinlu Liu ◽  
Jianming Guo ◽  
Yong Xu
Keyword(s):  
Acetic Acid ◽  
Reaction Time ◽  
Organic Acids ◽  
Formic Acid ◽  
Acid Hydrolysis ◽  
Environmental Benefits ◽  
Production Costs ◽  
Raw Material ◽  
Pka Values ◽  
Xylonic Acid

Abstract Background Methods to produce XOS have been intensively investigated, including enzymatic hydrolysis, steam explosion, and acid hydrolysis. Acid hydrolysis is currently the most widely used method to produce XOS due to its advantages of fewer processing steps, stronger raw material adaptability, higher yield, and better reproducibility. Especially, organic acids such as acetic acid, formic acid and xylonic acid work better as compared with mineral acids. However, the catalytic mechanism of different organic acids has been little studied. In this paper, four different organic acids, including formic acid, glycolic acid, lactic acid, and acetic acid were selected to compare their hydrolytic effects. Results Using pKa values as the benchmark, the yield of xylo-oligosaccharide (XOS) increased with the increasing value of pKa. The yield of XOS was 37% when hydrolyzed by 5% acetic acid (pKa = 4.75) at 170 ℃ for 20 min. Combined severity (CS), a parameter associated with temperature and reaction time was proposed, was proposed to evaluate the hydrolysis effect. The results of CS were consistent with that of pKa values on both the yield of XOS and the inhibitor. Conclusion The results based on pKa values and combined severity, a parameter associated with temperature and reaction time, concluded that acetic acid is a preferred catalyst. Combining the techno-economic analysis and environmental benefits, acetic acid hydrolysis process has lower factory production costs, and it is also an important metabolite and a carbon source for wastewater anaerobic biological treatment. In conclusion, production of xylo-oligosaccharides by acetic acid is an inexpensive, environment-friendly, and sustainable processing technique.

scholarly journals Comparison of various orgainc acids for xylo-oligosaccharide productions in term of pKa values and combined severity

2021 ◽  
Author(s):  
Rou Cao ◽  
Xinlu Liu ◽  
Jianming Guo ◽  
Yong Xu
Keyword(s):  
Acetic Acid ◽  
Reaction Time ◽  
Organic Acids ◽  
Formic Acid ◽  
Acid Hydrolysis ◽  
Environmental Benefits ◽  
Production Costs ◽  
Raw Material ◽  
Pka Values ◽  
Xylonic Acid

Abstract Background: Methods to produce XOS have been intensively investigated, including enzymatic hydrolysis, steam explosion, and acid hydrolysis. Acid hydrolysis is currently the most widely used method to produce XOS due to its advantages of fewer processing steps, stronger raw material adaptability, higher yield, and better reproducibility. Especially, organic acids such as acetic acid, formic acid and xylonic acid work better as compared with mineral acids. However, the catalytic mechanism of different organic acids has been little studied. In this paper, four different organic acids, including formic acid, glycolic acid, lactic acid, and acetic acid were selected to compare their hydrolytic effects.Results: Using pKa values as the benchmark, the yield of xylo-oligosaccharide (XOS) increased with the increasing value of pKa. The yield of XOS was 37% when hydrolyzed by 5% acetic acid (pKa=4.75) at 170℃ for 20 min. Combined severity (CS), a parameter associated with temperature and reaction time was proposed, was proposed to evaluate the hydrolysis effect. The results of CS were consistent with that of pKa values on both the yield of XOS and the inhibitor.Conclusion: The results based on pKa values and combined severity, a parameter associated with temperature and reaction time, concluded that acetic acid is a preferred catalyst. Combining the techno-economic analysis and environmental benefits, acetic acid hydrolysis process has lower factory production costs, and it is also an important metabolite and a carbon source for wastewater anaerobic biological treatment. In conclusion, production of xylo-oligosaccharides by acetic acid is an inexpensive, environment-friendly, and sustainable processing technique.

Lignin Separation and Antioxidant Capacity from Acanthopanax senticosus Remainders Using Acetic Acid-Water System

2011 ◽  
Vol 311-313 ◽  
pp. 1514-1517
Author(s):  
Ming Hua Zhu ◽  
Gui Zhen Fang ◽  
Shi Yan Han ◽  
Hai Hong Rong ◽  
Jun Guo ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Reaction Time ◽  
Antioxidant Capacity ◽  
Reaction Temperature ◽  
Water System ◽  
Solution Concentration ◽  
Acid Water ◽  
Acanthopanax Senticosus ◽  
Acetic Acid Water ◽  
Acetic Acid Lignin

Lignin was extracted from Acanthopanax senticosus remainders after pharmaceutical production process, with acetic acid-water as extracting reagent. Four factors effects, namely reaction temperature from 160°C to 220°C, reaction time from 40 min to 100 min, acetic acid concentration from 50% to 80% and solid-liquid ratio from 1:40 to 1:5, were studied and optimized by a four-level orthogonal array design (OAD) on lignin antioxidant capacity. The results indicated the reaction temperature and reaction time were significant factors among these factors. At the same lignin solution concentration, the acetic acid lignin antioxidant capacity was better than that of Kraft lignin, but much lower than that of butylated hydroxyanisole (BHA).

Furfural and Hydroxymethylfurfural as By-Products of FORMACELL Pulping

Holzforschung ◽  
2001 ◽  
Vol 55 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Ralph Lehnen ◽  
Bodo Saake ◽  
Horst H. Nimz
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Room Temperature ◽  
Oxidative Degradation ◽  
Solution Stability ◽  
Radical Scavengers ◽  
Long Time ◽  
Acetic Acid Water ◽  
High Yields ◽  
By Products

Summary The formation and stability of furans formed from pentoses and hexoses were studied in acetic acid/formic acid mixtures which are applied in the FORMACELL pulping process. For comparison, acetic acid/water mixtures with and without addition of HCl were included in the study. The investigations demonstrated that furfural can be obtained in high yields from xylose and xylan. Hexoses are converted to hydroxymethylfurfural (HMF), acetoxymethylfurfural (AMF) and furfural. Here, the water content of the reaction mixture influences the ratio of HMF and AMF in the solution. Stability studies revealed that furfural and HMF exhibit a high stability in acetic acid/formic acid mixtures. This explained the high furfural yields previously published for acetic acid pulping. The long-time stability of furans was investigated for 275 days at room temperature. No significant losses occurred suggesting that organic acids act as radical scavengers inhibiting oxidative degradation.

scholarly journals Comparison of Various Orgainc Acids for xylo-oligosaccharide Productions in Term of pKa Values and Combined Severity

2020 ◽  
Author(s):  
Rou Cao ◽  
Xinlu Liu ◽  
Jianming Guo ◽  
Yong Xu
Keyword(s):  
Acetic Acid ◽  
Reaction Time ◽  
Organic Acids ◽  
Formic Acid ◽  
Acid Hydrolysis ◽  
Environmental Benefits ◽  
Production Costs ◽  
Raw Material ◽  
Pka Values ◽  
Xylonic Acid

Abstract Background: Methods to produce XOS have been intensively investigated, including enzymatic hydrolysis, steam explosion, and acid hydrolysis. Acid hydrolysis is currently the most widely used method to produce XOS due to its advantages of fewer processing steps, stronger raw material adaptability, higher yield, and better reproducibility. Especially, organic acids such as acetic acid, formic acid and xylonic acid work better as compared with mineral acids. However, the catalytic mechanism of different organic acids has been little studied. In this paper, four different organic acids, including formic acid, glycolic acid, lactic acid, and acetic acid were selected to compare their hydrolytic effects.Results: Using pKa values as the benchmark, the yield of XOS increased with the increasing value of pKa. The yield of XOS was 37% when hydrolyzed by 5% acetic acid (pKa=4.75) at 170℃ for 20 min. Combined severity (CS), a parameter associated with temperature and reaction time was proposed, was proposed to evaluate the hydrolysis effect. The results of CS were consistent with that of pKa values on both the yield of XOS and the inhibitor.Conclusion: The results based on pKa values and combined severity, a parameter associated with temperature and reaction time, concluded that acetic acid is a preferred catalyst. Combining the techno-economic analysis and environmental benefits, acetic acid hydrolysis process has lower factory production costs, and it is also an important metabolite and a carbon source for wastewater anaerobic biological treatment. In conclusion, production of xylo-oligosaccharides by acetic acid is an inexpensive, environment-friendly, and sustainable processing technique.

scholarly journals Equilibrium and Kinetic Study of Anionic and Cationic Pollutants Remediation by Limestone–Chitosan–Alginate Nanocomposite from Aqueous Solution

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2586
Author(s):  
Inas A. Ahmed ◽  
Ahmed H. Ragab ◽  
Mohamed A. Habila ◽  
Taghrid S. Alomar ◽  
Enas H. Aljuhani
Keyword(s):  
Physical Adsorption ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Sem Images ◽  
Bet Analysis ◽  
Adsorption Processes ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Multilayer Formation

In this work, low-cost and readily available limestone was converted into nanolimestone chitosan and mixed with alginate powder and precipitate to form a triple nanocomposite, namely limestone—chitosan–alginate (NLS/Cs/Alg.), which was used as an adsorbent for the removal of brilliant green (BG) and Congo red (CR) dyes in aqueous solutions. The adsorption studies were conducted under varying parameters, including contact time, temperature, concentration, and pH. The NLS/Cs/Alg. was characterized by SEM, FTIR, BET, and TEM techniques. The SEM images revealed that the NLS/Cs/Alg. surface structure had interconnected pores, which could easily trap the pollutants. The BET analysis established the surface area to be 20.45 m2/g. The recorded maximum experimental adsorption capacities were 2250 and 2020 mg/g for CR and BG, respectively. The adsorption processes had a good fit to the kinetic pseudo second order, which suggests that the removal mechanism was controlled by physical adsorption. The CR and BG equilibrium data had a good fit for the Freundlich isotherm, suggesting that adsorption processes occurred on the heterogeneous surface with a multilayer formation on the NLS/Cs/Alg. at equilibrium. The enthalpy change (ΔH0) was 37.7 KJ mol−1 for CR and 8.71 KJ mol−1 for BG, while the entropy change (ΔS0) was 89.1 J K−1 mol−1 for CR and 79.1 J K−1 mol−1 BG, indicating that the adsorption process was endothermic and spontaneous in nature.

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