Investigation of reaction parameters and kinetics for the synthesis of sorbitol-branched azelaic acid ester

The renewable polyol ester produced from the esterification of isosorbide (ISB) and azelaic acid (AA) is substitute to petro-based polyol ester. The reaction of producing isosorbide azelaic acid ester (IAAE) has not been researched intensively and reported in the open literature. Sorbitol or its anhydrides fatty acid ester (SFAE) is typically produced by a homogeneously catalysed process which suffers with the undesired product colouration, corrosive process environment and complex downstream separation process. The unidentified reaction kinetics and correlation of the composition distribution of the sorbitol and its anhydrides with the operating parameters could render to the off specification SFAE. The present work investigated the effect of reaction parameters and kinetics for the synthesis of IAAE through sequential reactions constituted of heterogeneously catalysed sorbitol (SL) dehydration and ISB esterification with AA. Owing to the unavailability of the IAAE standards, the chromatography techniques to quantify the reactants during the esterification process was developed. The gas chromatography analysis of samples derivatised using silylation II with steady heating and reduced carrier gas flow rate outperformed others, producing identical and sharp peak for AA, SL and its anhydrides. Prior to the esterification reaction, the present study dehydrated SL to its anhydrides using the best heterogeneous catalyst, Amberlyst 36 at different important operating parameters. The increase of catalyst loading from 5 to 7 wt% did not significantly affect the ISB yield. A higher temperature increased the reaction rate, whereas a prolonged reaction time increased the conversion of SL and yield of ISB to the maximum. In terms of giving a higher ISB yield during SL dehydration, Amberlyst 36 was found to outperform the other resin catalysts reported in the literature. Both SL conversion and ISB yield of >99% were recorded after a 4 h reaction at 423 K with a catalyst loading of 5 wt% and stirring speed of 300 RPM. The reaction kinetics was evaluated under a mass transfer resistances free condition at the reaction temperature ranged from 373 K to 423 K. The kinetic data well fitted to the Langmuir-Hinshelwood (LH2) model that took side reaction into account. The activation energy for dehydration SL to sorbitan (ST), dehydration ST to ISB and dehydration of SL to other side products such as humins were 109.22, 109.46 and 104.17 kJ/mol respectively. ISB produced from SL dehydration was reacted with AA catalysed by graphite to synthesis the monomer for renewable polyol ester. The critical parameters that influence the product distributions were investigated. It encompassed the stirring speed (0-500 RPM), catalyst particle size (18-120 MESH), catalyst loading (0-2 wt%), the molar ratio of AA to ISB (1:1 to 1:5 and 1:1 to 3:1) and reaction temperature (373-473 K). The best mass-transfer resistance-free condition that maximising the amount of isosorbide monoazelate (ISMA) was found in the reaction catalysed by 1 wt% of graphite catalyst with the particle size ranged 25-35 MESH and adopted an equimolar of AA and ISB with stirring speed of 300 RPM. Meanwhile, the best reaction temperature was identified as 433 K, considering the tradeoff between reasonable reaction rate and product quality. The Langmuir Hinshelwood Hougen Watson (LHHW) model well predicted the concentration profile of the esterification of ISB with AA, estimating activation energy of 26.12 kJ/mol. The current research has proven that the heterogeneously catalysed process, with sequential reactions of the SL dehydration followed by ISB esterification, is promising method to produced IAAE at milder condition

Iron-based nanoparticles oxygen scavenger for suppressing heat-stable salts formation in amine

Heat-stable salts (HSS), which trigger excessing foaming in absorber, are formed when protonated methyl diethanolamine (MDEA) reacts with the more acidic degraded products in the presence of dissolved oxygen (DO). The aim is to suppress the HSS formation in MDEA solution inaugurally employing a hybrid iron-based nanoparticles (HINP) oxygen scavenger. It was discovered that the oxygen-scavenging performance of a more cost-effective 20 %Fe/HZSM5 was one-fold higher than the 20 %Fe/MCM-41. The former was verified for its superior structural properties. The Fe2+ on its surface first reacted with DO, preventing DO from oxidizing the MDEA. Consequently, the absence of hydroxyl radicals eliminated the potential of formic acid formation, hence suppressing the MDEA-acid HSS formation

Chemical Equilibrium and kinetic study of the esterification of acrylic acid with butanol catalysed by sulfonated expanded polystyrene

The wastewater containing low concentration (4-10 wt %) of acrylic acid (AA) was treated by incineration since it is very toxic to the organism if it is discharged to the environment. This valuable compound can be recovered using one of the promising methods, the esterification of the diluted AA with alcohol. The sulfonated expanded polystyrene (SEP) from waste expanded polystyrene is a good catalyst to catalyse the esterification of AA with butanol (BuOH). The production of this catalyst can have high impact in environment since the waste polystyrene is huge environmental issues. The SEP was synthesised via the sulfonation of waste expanded polystyrene using sulphuric acid (H2SO4) at 378 K. The slurry obtained after 2 hour of sulfonation was transferred into water and washed with sodium hydroxide, acid hydrochloric and excess water before dried at 343 K. The SEP has a rough surface with minute cracks, can withstand up to 403 K and density of 1.2790 g/cm3. The swelling effect in SEP helps the reactant access the active sites. The activity and kinetic study for this esterification reaction was carried out in batch system. The effect of various parameters that affecting conversion and yield such as stirring speed, initial molar ratio of AA to BuOH, catalyst loading, temperature and initial water content were studied. The reaction was more sensitive to temperature as compared to other parameters. The best conversion and yield obtained at molar ratio AA to BuOH of 1:3, catalyst loading of 10 wt% and temperature of 353 K were 92% and 75% respectively. The yield of butyl acrylate decrease with the increase of initial water content in the reaction mixture because water shifts the reaction equilibrium to reactants, blocked the reactants from accessing active sites and increase polymerisation on the SEP surface. Nevertheless, the SEP can be regenerated easily using sulphuric acid. The experimental kinetic data was correlated to the several kinetic models which were pseudo-homogeneous (PH), Eley-Rideal (ER) and Langmuir Hinshelwood Hougen Watson (LHHW) model. The activation energy is 73.6 kJ/mol. The best fitted model for the main esterification reaction was shown by the non-ideal ER I model. Taking the polymerisation into account, the experimental data are more comparable with the predicted dat

Isolation of microorganism from oil palm-sap

Oil palm sap is obtained from squeeze the oil palm trunk. The sap is good medium because rich of nutrients for yeast growth. The objectives of this research are to isolate and identify the yeast species from oil palm sap and determine the growth kinetic of the mix culture of yeast. The isolation of yeast is using streaking method that streak on sabouraud dextrose agar and incubate for 30oC and 48 hours for development yeast colonies on the agar plate. The yeast colonies will re-streak to get pure colonies. The pure colonies are identified by using morphological and biochemical test to determine the species. The growth kinetics are based on Monod kinetics which using cell dried weight and substrate concentration taken every 4 hours until the reading constant or decline. The yeast species in the oil palm sap are Candida spp., Hansenula spp., Fisobasidiella spp., Saccharomyces spp., Pichia spp., Sporobolomyces spp. and Trichosporon spp. The growth kinetics values are 0.0288 (yield coefficient), 0.0058h-1 (decay coefficient), 0.3509h-1 (maximum growth rate) and 1850.711mg/l (half saturation constant). As conclusion, the yeast species can obtain from oil palm sap and can be used for further research

Screening of catalysts and operating conditions for the high yield production of isosorbide from sorbitol dehydration

Isosorbide (ISB), one of the important sorbitol (SL) anhydrides, can be produced through sequential intra-molecular dehydration of sorbitol derived from renewable biomass resources. Its rigid structure has granted the ISB a wide application in the polymer industries. Conventionally, acidic catalyst in liquid phase was used in the SL dehydration process. This homogeneous catalysed reaction gave low ISB yield and required additional downstream processes for catalyst separation. In the present study, a few types of catalysts were screened for sorbitol dehydration at a mild condition. Amberlyst 36 outperformed the other catalysts and resulted the highest SL anhydride selectivity of 86%. The effects of nitrogen purging and catalyst pre-treatment to the reaction performance were also investigated. The purging system did not significantly affect the SL conversion and selectivity of the desired products. The used of dried Amberlyst 36 exhibited a positive impact by increasing the SL conversion and SL anhydride selectivity to 67% and 98% respectively

New Method For Acrylic Acid Recovery From Industrial Waste Water Via Esterification With 2-Ethyl Hexanol

Acrylic acid (AA) is an important component for the production of acrylate polymer. In a typical acrylic manufacturing unit, waste water contains AA in a range of 4–15wt.% contributes to the high values of chemical oxygen demand. Due to the toxicity of AA to the aquatic organism, this wastewater should be treated before it is discharged to the environment. The waste water could be evaporated before sending to the incineration which was neither economic feasible nor environmental friendly. Esterification of wastewater containing carboxylic acid with alcohol could be a promising method to recover the acid by converting it to ester while purifying the wastewater. In the present study, recovery of AA via esterification with 2-ethyl hexanol (2EH) was investigated. The model industrial wastewater with various concentration of AA (10–100% w/w) was reacted with 2EH to produce 2-ethyl hexyl acrylate (2EHA) in the setups with total reflux and continuouslywater removal. These Amberlyst-15 (ion exchange resin) catalyzed reactions were carried out under the mass transfer resistance free region. The performance of both systems was compared. The yield for the reactions of the AA solutions with the AA concentrations of 30–80% was enhanced significantly when the reactions were carried out using the second setup. The kinetic data of the esterification of dilute AA was well described by the Eley–Rideal (ER) kinetic model incorporated with a correction factor to consider the catalyst fouling effect and pseudo-homogeneous (PH) kineticmodel for the AA polymerization. The findings have shown the potential of recovering AA from the waste water stream via esterification. The concentrated AA solutions or larger amount of inhibitor should be adopted to prevent the catalyst fouling by the deposition of poly-acrylic acid on the catalyst surface

Bio-based sorbitol azelaic acid ester synthesis through germanium (IV) oxide catalysed esterification

Conventionally, polyurethane (PU) is derived from the non-renewable petroleum feedstocks, polyol polyester and di-isocyanate. Bio-based polyol polyester is an alternate to reduce the environmental impacts of the petroleum-based polyol polyester. Bio-based reactants, sorbitol (SL) and azelaic (AA) acid were used in the esterification to produce sorbitol azelaic acid ester (SAAE) using germanium (IV) oxide (GeO2) as a catalyst. The experimental studies set at various operating conditions were conducted to determine the best operating condition that gave product with highest AA conversion and acceptable colour. The best operating condition was achieved at a temperature of 200°C, SL/AA reactant ratio of 4:1 and catalyst loading of 0.5 wt%, with the corresponding AA conversion of 90.10%. The kinetic data was well fitted to the Langmuir Hinshelwood Hougen Watson (LHHW) model with the corresponding activation energy of 11.55 kJ/mol

High yield of isosorbide production from sorbitol dehydration catalysed by Amberlyst 36 under mild condition

Isosorbide (ISB), one of the important polyols, can be produced through the sequential intramolecular dehydration of sorbitol (SL) derived from an abundance renewable biomass resources. The advantages of its rigid structure have granted the ISB a wide application in the polymer industries. An acidic catalyst in the liquid phase was conventionally used in the dehydration process. This homogeneously catalysed reaction gave low ISB yield and required additional downstream processes to separate the catalyst. The present study employed solid acidic ion exchange resin, Amberlyst 36 in the SL dehydration at a mild condition. The effect of important operating parameters such as stirring speed, catalyst loading, temperature and reaction time was investigated. The increase of catalyst loading from 5 to 7 wt% did not significantly affect the ISB yield. A higher temperature increased the reaction rate whereas a prolonged reaction time increased the conversion of SL and yield of ISB to the maximum. In terms of giving a higher ISB yield during SL dehydration, AM 36 was found to outperform the other resin catalysts reported in the literature. Both SL conversion and ISB yield of>99% were recorded after a 4 h reaction at 423 K with catalyst loading of 5 wt% and stirring speed of 300 RPM. The reaction kinetics was evaluated under a mass transfer resistances free condition at the reaction temperature ranged from 373 K to 423 K. The kinetic data well fitted to the Langmuir-Hinshelwood (LH2) model that took side reaction into account. The activation energy for dehydration SL to ST, dehydration ST to ISB and dehydration of SL to other side products such as humins were 109.22, 109.46 and 104.17 kJ/mol respectively