Synthesis of Several Sugar Acetates and their Structures Characterization

2012 ◽  
Vol 602-604 ◽  
pp. 1373-1378
Author(s):  
Jing Liang ◽  
Zhen Xing Cheng ◽  
Lian Yuan Wang ◽  
Hai Yan Zhu ◽  
Shi Gao ◽  
...  
Keyword(s):  
Reaction Time ◽  
Acetic Anhydride ◽  
Reaction Temperature ◽  
Soluble Starch ◽  
Degree Of Substitution ◽  
High Yield ◽  
Reaction Conditions ◽  
Alkaline Catalyst ◽  
Acetate Esters ◽  
Acidic Catalyst

Several acetate esters were synthesized by reacting sugars, i.e. glucose, soluble starch, and dextrin, with acetic anhydride in the presence of some catalysts. Their structures were confirmed by IR and MS. Influences of the reaction conditions, such as catalyst and its dosage, reaction time, reaction temperature and acetic anhydride content, on the value of degree of substitution (DS) and the yield for starch acetates had also been investigated. Results showed that glucose could be easily completely acetylated; acidic catalyst tended to form a configuration of α-glucose penta-acetate (α-GPA), while alkaline catalyst β-GPA. However, soluble starch and dextrin were more difficult to be completely substituted by acetic anhydride. The DS value of soluble starch was below 2; for dextrin, its DS value could reach 2.3, close to the theoretical value of 3. An appropriate reaction temperature and reaction time were important for high yield as well as high DS value.

scholarly journals Synthesis of propylene carbonate from urea and 1,2-propylene glycol over metal carbonates

2011 ◽  
Vol 17 (3) ◽  
pp. 323-331 ◽  
Author(s):  
Jiancheng Zhou ◽  
Wu Dongfang ◽  
Birong Zhang ◽  
Yali Guo
Keyword(s):  
Reaction Time ◽  
Propylene Glycol ◽  
Propylene Carbonate ◽  
Reaction Temperature ◽  
Reaction Conditions ◽  
Lead Carbonate ◽  
Synthetic Process ◽  
Metal Carbonates ◽  
Optimal Reaction ◽  
Mixed Carbonate

A series of single-metal carbonates and Pb-Zn mixed-metal carbonates were prepared as catalysts for alcoholysis of urea with 1,2-propylene glycol (PG) for the synthesis of propylene carbonate (PC). The mixed carbonates all show much better catalytic activities than the single carbonates, arising from a strong synergistic effect between the two crystalline phases, hydrozincite and lead carbonate. The mixed carbonate with Pb/Zn=1:2 gives the highest yield of PC, followed by the mixed carbonate with Pb/Zn=1:3. Furthermore, Taguchi method was used to optimize the synthetic process for improving the yield of PC. It is shown that the reaction temperature is the most significant factor affecting the yield of PC, followed by the reaction time, and that the optimal reaction conditions are the reaction time at 5 hours, the reaction temperature at 180 oC and the catalyst amount at 1.8 wt%, resulting in the highest PC yield of 96.3%.

Synthesis of a Ruthenium Complex Based on 2,6-Bis[1-(Pyridin-2-yl)-1H-Benzo[d]Imidazol-2-yl]Pyridine and Catalytic Oxidation of (1H-Benzo[d]-Imidazol-2-yl)Methanol to 1H-Benzo[d]Imidazole-2-Carbaldehyde with H2O2

2017 ◽  
Vol 41 (2) ◽  
pp. 88-92
Author(s):  
Shenggui Liu ◽  
Rongkai Pan ◽  
Wenyi Su ◽  
Guobi Li ◽  
Chunlin Ni
Keyword(s):  
Reaction Time ◽  
Catalytic Oxidation ◽  
Reaction Temperature ◽  
Ruthenium Complex ◽  
Reaction Conditions ◽  
Molar Ratios ◽  
Optimal Reaction

2,6-Bis[1-(pyridin-2-yl)-1H-benzo[d]-imidazol-2-yl]pyridine (bpbp), which has been synthesised by intramolecular thermocyclisation of N2,N6-bis[2-(pyridin-2-ylamino)phenyl]pyridine-2,6-dicarboxamide, reacts with sodium pyridine-2,6-dicarboxylate (pydic) and RuCl3 to give [Ru(bpbp)(pydic)] which can catalyse the oxidation of (1H-benzo[d]imidazol-2-yl)methanol to 1H-benzo[d]imidazole-2-carbaldehyde by H2O2. The optimal reaction conditions were: molar ratios of catalyst to substrate to H2O2 set at 1: 1000: 3000; reaction temperature 50 °C; reaction time 5 h. The yield of (1H-benzo[d]imidazol-2-yl) methanol was 70%.

scholarly journals Microwave Assisted One Pot Synthesis of 3,4-Dihydropyrano[c]chromene Derivatives using [Emim]OH Ionic Liquid as Novel Catalyst

2019 ◽  
Vol 31 (4) ◽  
pp. 829-833
Author(s):  
D.S. Bhagat ◽  
S.G. Pande ◽  
M.V. Katariya ◽  
R.P. Pawar ◽  
P.S. Kendrekar
Keyword(s):  
Ionic Liquid ◽  
Reaction Time ◽  
High Yield ◽  
Reaction Conditions ◽  
One Pot ◽  
Short Reaction Time ◽  
Aryl Aldehydes ◽  
Microwave Assisted ◽  
Novel Catalyst ◽  
Work Up

One-pot efficient protocol to the synthesis of 2-amino-5-oxo-4,5-dihydropyrano(3,2-c)chromene-3-carbonitrile derivatives via condensation of various aryl aldehydes, dicyanomethane and 4-hydroxycoumarin in presence of Emim hydroxide as an excellent homogeneous liquid catalyst. The key advantages of this methodology are mild reaction conditions, novel catalyst, short reaction time, eco-friendly, easy work-up procedure and high yield of isolation of derivatives.

Preparation and Characterization of Cationic Cassia Tora Gum

2013 ◽  
Vol 781-784 ◽  
pp. 526-530 ◽  
Author(s):  
Shao Ying Li ◽  
Chun Mei Niu ◽  
Hua Yu Zhong
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Water Solubility ◽  
Cold Water ◽  
Water Solution ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Cassia Tora ◽  
Dispersing Agent

Series of cationic cassia tora gum (CCTG) were synthesized using 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) as cationic etherifying agent, isopropanol-water solution as dispersing agent, in presence of sodium hydroxide under different reaction conditions. The optimum ratio for preparing the cationic cassia tora gum are that CHPTAC-CTG molar ratio is 0.6:1; NaOH-CHPTAC molar ratio is 1.3:1.The optimum conditions are that reaction temperature is 55°Cand reaction time is 3.5 h. The cold water solubility was improved apparently. The solution transmittance has corresponding relationship with the nitrogen content (N%) in the certain range, and the maximum transmittance is up to 87.2%. N% increased with the increase of reaction time and stable N% can be obtained in shorter reaction time at higher reaction temperature. The products were characterized by 13C-NMR. The heat resistance of CTG and CCTG were analyzed.

The Synthesis of High Yield Diglycerin Borate

2011 ◽  
Vol 55-57 ◽  
pp. 312-316
Author(s):  
Qi Wang ◽  
Guo Zheng ◽  
Jian Jie Ai ◽  
Xue Jing Wei
Keyword(s):  
Boric Acid ◽  
Reaction Temperature ◽  
Raw Materials ◽  
High Yield ◽  
Optimum Process ◽  
Process Conditions ◽  
Temperature Reaction ◽  
Reaction Conditions ◽  
Reaction Pressure

High yield diglycerin borate(DGB) have been synthesized by the raw materials glycerol and boric acid in this paper. The structure of the products was characterized by FTIR and11B NMR. The yield of the products was discussed by reaction conditions that were material ratio, reaction temperature, reaction pressure etc. and then the optimum process conditions of preparing DGB was decided. In this condition, high yield DGB can be prepared which could reach more than 96%.

Synthesis of Butanone 1,2 - Propanediol Ketal by Sulfamic Acid as Catalyzed

2013 ◽  
Vol 781-784 ◽  
pp. 276-279
Author(s):  
Yu Hang Zhao ◽  
Li Cui ◽  
Da Zhi Wang ◽  
Tong Kuan Xu ◽  
Yong Peng Li
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Raw Materials ◽  
Sulfamic Acid ◽  
Product Yield ◽  
Experimental Results ◽  
Reaction Conditions ◽  
Optimal Reaction

Butanone 1,2-propanediol ketal was synthesized by butanone and 1,2-propanediol as raw materials and sulfamic acid as catalyst. The effects of the mole ratio of raw materials agent, the dosage of the water-carrying agent and catalyst, reaction time on the product yield were discussed separately. Experimental results showed that sulfamic acid was a suitable catalyst for synthesizing of butanone 1,2-propanediol ketal. And the optimal reaction conditions are as follows: the mole ratio of butanone to 1,2-propanediol is 1:1.5, the amount of the catalyst is 2.2%, the water-carrying agent is 25ml, the reaction temperature is 358-378K and reaction time 3h. In this condition, the yield of production could reach 93.8%.

Synthesis of Diethyl Carbonate from Ethyl Carbamate and Ethanol with Acid as Catalyst

2013 ◽  
Vol 821-822 ◽  
pp. 1081-1084 ◽  
Author(s):  
Xian Ye Qin ◽  
Biao Liu ◽  
Bing Han ◽  
Wen Bo Zhao ◽  
Shui Sheng Wu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Ethyl Carbamate ◽  
Diethyl Carbonate ◽  
Bronsted Acid ◽  
Optimal Conditions ◽  
Reaction Conditions ◽  
Brönsted Acid ◽  
Pyrophosphoric Acid

The catalytic activity of many Lewis and Bronsted acid for the synthesis of diethyl carbonate (DEC) from ethyl carbamate (EC) and ethanol was evaluated in a bath reactor. Pyrophosphoric acid (H4P7O2) which showed the best activity was selected to further investigate the effect of reaction conditions, such as reaction temperature, catalyst dose and reaction time, on the yield of DEC. Under the optimal conditions, DEC yield can reach 29.1%.

Improve the Temperature Resistance of Guar Gum by Silanization

2011 ◽  
Vol 415-417 ◽  
pp. 652-655
Author(s):  
Jie Zhang ◽  
Gang Chen
Keyword(s):  
High Temperature ◽  
Reaction Time ◽  
Hydraulic Fracturing ◽  
Reaction Temperature ◽  
Guar Gum ◽  
Molar Ratio ◽  
Fracturing Fluid ◽  
Reaction Conditions ◽  
Temperature Resistance ◽  
Optimized Conditions

For gelating agent in hydraulic fracturing fluid, the temperature resistance is required. To improve the temperature resistance of Guar gum (GG), it was modified by silanization. The reaction conditions were investigated, and the optimized conditions were as following: the reaction temperature of 85°C, 5: 1 molar ratio of guar gum to TMS-Cl and 4-6 h of reaction time. The viscosity of silanized guar gum (SGG) aqueous gel was greatly improved even high temperature at 80°C.

Effects of Microwave and Additional Co–Solvents on Two–Stage Waste Cooking Oil to Biodiesel Conversion

2012 ◽  
Vol 209-211 ◽  
pp. 1136-1141
Author(s):  
Ming Chien Hsiao ◽  
Yung Hung Chang ◽  
Li Wen Chang
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Waste Cooking Oil ◽  
Molar Ratio ◽  
Phase System ◽  
Reaction Conditions ◽  
Two Stage ◽  
Second Stage ◽  
Cooking Oil ◽  
Standard Value

This paper introduced a better solution to accelerating the production of biodiesel from waste cooking oil by using suitable acidic and alkaline catalysts in a two-stage catalytic reaction. Next, a co-solvent named tetrahydrofuran (THF), which significantly increased mixing level of the reactants in the mixture of vegetable oil and methanol, was added to form a single phase system. The whole system was then put into a microwave oven to support heat for the transesterification of biodiesel to shorten the reaction time. Reaction conditions of the first stage were methanol to oil molar ratio of 9:1, catalyst amount 1wt%, reaction temperature 60 oC and reaction time 7.5 minutes. In the second stage, for the transesterification, reaction conditions were methanol to oil molar ratio 12:1, catalyst loadings 1 wt%, reaction temperature 60 oC and reaction time 1.5 minutes. Finally, the conversion rate of biodiesel after the nine-minute reaction time was 97.38% which was higher than the EU EN14214 standard value of 96.5%.

scholarly journals Enhancement of Biodiesel Production from Marine Alga,Scenedesmussp. throughIn SituTransesterification Process Associated with Acidic Catalyst

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Ga Vin Kim ◽  
WoonYong Choi ◽  
DoHyung Kang ◽  
ShinYoung Lee ◽  
HyeonYong Lee
Keyword(s):  
Reaction Time ◽  
Biodiesel Production ◽  
Matrix Analysis ◽  
Solvent Ratio ◽  
Alkaline Catalyst ◽  
Catalyst Amount ◽  
Acidic Catalyst ◽  
Lipid Weight ◽  
Level 2

The aim of this study was to increase the yield of biodiesel produced byScenedesmussp. throughin situtransesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36%) > catalyst (28.62%) > time (19.72%) > temperature (17.32%). The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4in an acidic process, at 55.07 ± 2.18% (based on lipid weight) versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70°C (level 2), reaction time of 10 hrs (level 2), catalyst amount of 5% (level 3), and biomass to solvent ratio of 1 : 15 (level 2), respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction within situtransesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from aScenedesmussp.

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