Thermodynamics Properties of 1,1-Carbonyldiimidazole (CDI) and 4-Imidazole Acrylic Acid, Obtained by DSC and Combustion Calorimetry

In this work, thermodynamic properties of 1,1-carbonyldiimidazole (CDI) and 4-imidazole acrylic are reported. The melting temperature, the enthalpy of fusion and the heat capacity of the compounds were determined by differential scanning calorimetry. The standard molar energy of combustion of both compounds were determined by static-bomb combustion calorimetry and the standard molar enthalpy of formation in the crystalline phase, at T = 298.15 K, was derived and evaluated for the two imidazole derivatives studied. The energetic influence of the acrylic group on the imidazole ring in each of the properties obtained is analyzed and compared with the existing results in the literature. Resumen. Se presentan las propiedades termodinámicas del 1,1-carbonildiimidazol (CDI) y el 4-imidazol acrílico. La temperatura de fusión, la entalpía de fusión y la capacidad calorífica de los compuestos se determinaron mediante calorimetría diferencial de barrido. La energía molar estándar de la combustión de ambos compuestos se determinó mediante calorimetría de combustión en bomba estática y la entalpía de formación en fase cristalina, a T= 298.15, fue derivada y evaluada para los dos compuestos derivados del imidazol. La influencia energética del grupo acrílico sobre el anillo de imidazol en cada una de las propiedades obtenidas se analiza y compara con los resultados existentes en la literatura.

Photophysics of Caffeic, Ferulic and Sinapic Acids with α- and β-Cyclodextrins: Spectral and Molecular Modeling Studies

Encapsulation of caffeic acid (CAA), ferulic acid (FEA) and sinapic acid (SIA) molecules with α-CD and β-CD was studied by UV-visible, fluorescence, time-resolved fluorescence and molecular modelling techniques. This analysis reports the probing of cyclodextrin (CD) cavities with the help of dual emission properties of the above hydroxycinnamic acids (HCAs) in aqueous solution. The normal Stokes shifted bands originated from the locally excited state and the large Stokes shifted bands due to the emission from an intramolecular charge transfer (ICT) state were observed. The ratio of the TICT emission to the normal emission increased with α-CD and β-CD concentration. CD studies indicates (i) HCAs forms 1:1 inclusion complex and (ii) acrylic group present in the interior part of the CD cavity and OH/OCH3 groups present in the upper part of the CD cavity. pH studies suggest proton transfer reactions follow the same trend in these molecules. A mechanism is proposed to explain the inclusion process. PM3 optimizations were also carried out to assign the encapsulation of the HCA molecules.

Synthesis and Characterization of Ethyl Cellulose Based Acrylate

Ethyl cellulose based acrylate (AEC), an ethyl cellulose based macromonomer, was successfully synthesized by the esterificaiton reaction between ethyl cellulose and acryloyl chloride in homogeneous media and characterized by FTIR,1H NMR,13C NMR, differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The results showed that acrylic group was facilely grafted onto the backbone of ethyl cellulose. In addition, AEC was proved to be able to homopolymerize and copolymerize with other monomers such as butyl acrylate in the presence of free radical polymerization initiator. We believed that development of AEC together with the analysis of its structure and properties would contribute to further utilization of cellulose based materials.

Comparison of Sulcus Implantation of Single-Piece Hydrophilic Foldable Acrylic and Polymethylmethacrylate Intraocular Lenses in Eyes with Posterior Capsule Tear during Phacoemulsification Surgery

Purpose To compare the results of sulcus implantation of acrylic and poly(methylmethacrylate) (PMMA) intraocular lens (IOL) in eyes with posterior capsule tear during phacoemulsification surgery. Methods In all eyes a posterior capsule tear developed during phacoemulsification surgery and an IOL to the ciliary sulcus was implanted primarily. A total of 89 eyes of 88 patients received hydrophilic foldable acrylic IOL (acrylic group). A total of 72 eyes of 72 patients received PMMA IOL (PMMA group). The mean age was 67.1 years and 68.1 years and postoperative follow-up period was 19.2 months and 17.9 months in acrylic and PMMA groups, respectively. Results Temporary corneal edema appeared in 33 eyes and 26 eyes, elevation of intraocular pressure in 17 eyes and 12 eyes, anterior chamber inflammatory reaction in 5 eyes and 5 eyes, clinical cystoid macular edema in 7 eyes and 12 eyes, and decentered IOL in 4 eyes and 3 eyes in acrylic and PMMA groups, respectively. Late postoperative endophthalmitis developed in two eyes of the PMMA group. Rhegmatogenous retinal detachment developed in one eye in each group. Final best-corrected visual acuities were 5/10 and above in 73 eyes (82.02%) in the acrylic group and 5/10 and above in 42 eyes (58.33%) in the PMMA group. Postoperative final induced astigmatism was 0.5±0.5 D (SD) in the acrylic group and 1.11±0.65 D (SD) in the PMMA group (p=0.0001) (independent samples t-test). Conclusions Increased astigmatism is more frequently seen in the PMMA group. The implantation of foldable acrylic IOL in the sulcus after posterior capsule tear maintains the advantages of small incision surgery.