Extended rate-based model validation for polyester synthesis by reactive distillation

Kinetic analysis for the acid-catalyzed dimerization of C4 olefins was performed in a batch reactor, and a suitable rate model was developed. It was further used in the rate-based simulation model of a continuous reactive distillation (RD) column. The results obtained were compared with the experimental observations made on a pilot-scale high-pressure RD column. An important outcome of the present work is that RD can be used efficiently to enhance the selectivity of C8 dimers, thereby avoiding the formation of trimers and tetramers. The use of polar components (such as water or alcohols), as selectivity enhancers, is not necessary.

Synthetic polymer single-chain nanoparticles (SCNPs) are an emerging new class of nanomaterials that possess similar folded structures as natural proteins. However, most SCNPs reported so far are p...

Synthesis of polyesters by reaction of carboxylic acid quaternary ammonium salts with alkyl halides or alkyl tosylates

Dynamic behaviour of reactive distillation tray columns described with a nonequilibrium cell model

A model for bulk polymerization of styrene was established by using the POLYMER module of ASPEN PLUS. The effects of the chain initiator (TBP), solvent (ethylbenzene) and the chain transfer agent (DDM) on the yield, number average degree of polymerization(DPN), weight average degree of polymerization(DPW), number average molecular weight(Mn), weight average molecular weight(Mw) and the polydispersity index(PDI) of polystyrene were investigated. Through the analysis, we can first consider the amount of styrene to obtain roughly the parameters of the polystyrene process. As the use of initiator in polymerization has the optimal value, we must strictly control the amount of TBP according to the amount of monomer styrene, and adjust the amount of chain transfer agent to control the product quality accurately.

Fatty acid methyl esters derived from renewable sources such as vegetable oils has gained importance nowadays as an alternative fuel for diesel engines. The present study is aimed to produce biodiesel from non-edible oil (Karanja oil of Indian origin) both in batch and continuous reactors. The purpose of the study is the comparison of Karanja biodiesel production with different reactor types under variable reaction characteristics. Therefore, two types of continuous reactors were used: helical tube reactor and reactive distillation (RD) column. Experiments were carried out to obtain suitable operating parameters in batch- and continuous-flow reactors. For batch reactor, suitable operating conditions obtained are: 7:1 methanol-to-oil molar ratio, 0.8% (by weight of oil) catalyst (KOH), 65°C reaction temperature, and 1-h reaction time, at which the maximum yield obtained is 96%. In continuous helical tube reactor, maximum yield of 92.6% was obtained at 6.6 mL/min of flow rate at the same operating conditions of batch reactor. In continuous RD column, maximum yield of biodiesel 96.6% was obtained at the same operating conditions except methanol-to-oil molar ratio (5:1) because of recycling of methanol into the column. The residence times in the helical tube reactor and RD column were 4 and 8 min, respectively, as compared to 1 h in the batch reactor for almost the same yield.

Development of a dynamic nonequilibrium cell model for reactive distillation tray columns

Innovative dimethyl ether synthesis in a reactive dividing-wall column

Attainable region of reactive distillation—Part IV: Inclusion of multistage units for complex reaction schemes

Dynamic modeling and simulation of reactive batch distillation

Optimal retrofit of a CO2 capture pilot plant using superstructure and rate-based models

Simulation Studies and Sensitivity Analysis of Methyl Tert-butyl Ether Reactive Distillation

The Lewis acid, titanium (IV) butoxide [15% (w/w; catalyst/reactants)], was used to catalyze the condensation of 0.05 mol glycerol with 0.10 mol of succinic acid, glutaric acid, and azelaic acid to produce oligomers. The reactions were refluxed in dilute solutions of dimethylsulfoxide (DMSO) or dimethylformamide (DMF) for 24 h. The oligomers were obtained, on average, in 84% yield and were soluble in polar organic solvents. Analysis by gel permeation chromatography determined that the oligomers had a number of average molecular weights (Mn) ranging from 2,118 to 3,245 g/mol, with degrees of polymerization (DOP) ranging from 12.2 to 13.4 repeat units. The oligomers had low polydispersities (Mw/Mn) that averaged ≈1.33. Degrees of branching were determined by one‐dimensional and two‐dimensional 1H NMR and 13C NMR and varied from 25 to 80%. Like Mn and the DOP values, the degrees of branching were dependent on the aliphatic chain length of the diacid. MALDI‐TOF mass spectrometry was used to detect ionated species that were unique to branched molecules. It was also used to validate NMR studies that suggested that some diacids were terminated with dimethylamine, generated from the hydrolysis of DMF, by as much as 36%.

Novel polyimides containing thermoplastic and thermosetting merged segments in a chain have been developed via Diels-Alder intermolecular reaction of bisfuran A and bismaleimides B1-3. Thus, obtained intermediate Diels-Alder adducts C1-3 were aromatized and imidized (cyclized) through carboxylic and amide groups in the presence of acetic anhydride to afford polyimides D1-3. Bisfuran was prepared by condensation of pyromellitic dianhydride with furan-2-ylmethanamine and characterized by elemental, spectral and thermal technique. Synthesized Diels-Alder adducts and polyimides were characterized by elemental analysis, spectral features, number average molecular weight (Mn), degree of polymerization (DP) and thermal analysis. To facilitate the correct structural assessment and to be able to verify the occurrence of the polyimides, a model compound was prepared from phthalic anhydride and furan-2-ylmethanamine in a similar way. FTIR spectral features of polyimides D1-3 were compared with model compound and it was found to be quite identical. The ‘in situ’ glass fiber reinforced composites GFRC1-3 were prepared from the produced system and were characterized by chemical, mechanical and electrical analysis. All the composites depicted good mechanical and electrical properties and good resistance to organic solvents and mineral acids.

Novel thermoplastic–thermosetting merged polyimides (PIs) have been developed by Diels–Alder (DA) intermolecular reaction of the bisfuran 2,5-bis(furan-2-ylmethylcarbamoyl)terephthalic acid A with a series of bismaleimides, viz., m,m′-dimethyl p,p′-dimaleimidobiphenyl (B 1 ), m,m′-dimethoxy p,p′-dimaleimidobiphenyl (B 2 ), 1,1′-bis(4-maleimidophenyl)cyclohexane (B 3 ), and 2,2′-bis-[4-(4-maleimidephenoxy)phenyl]propane (B 4 ). The intermediate DA adducts obtained, C 1–4 , were aromatized and imidized (i.e. cyclized) through the carboxyl and amide groups to afford thermoplastic–thermosetting merged PIs D 1–4 . Bisfuran A was prepared by condensation of pyromellitic dianhydride with furan-2-ylmethanamine and duly characterized. Synthesized DA adducts and PIs were characterized by use of elemental analysis, spectral features, number average molecular weight, degree of polymerization, and thermal analysis. To facilitate the correct structure assignment and to verify the identities of the DA adducts and PIs, a model compound 4 was prepared in a similar way from phthalic anhydride and furan-2-ylmethanamine. FT-IR spectral features of PIs D 1–4 were compared with those of model compound 4 and found to be identical. Glass fiber-reinforced composites GFRC 1–4 were prepared from this system and characterized by chemical, mechanical, and electrical analysis. All the composites had good mechanical, electrical, and thermal properties and good resistance to organic solvents and mineral acids.