Process Analysis of PMMA-Based Dental Resins Residues Depolymerization: Optimization of Reaction Time and Temperature was written by dos Santos, Jr. Paulo Bisi;Ribeiro, Haroldo Jorge da Silva;Ferreira, Armando Costa;Ferreira, Caio Campos;Bernar, Lucas Pinto;Assuncao, Fernanda Paula da Costa;de Castro, Douglas Alberto Rocha;Santos, Marcelo Costa;Duvoisin, Jr. Sergio;Borges, Luiz Eduardo Pizarro;Machado, Nelio Teixeira. And the article was included in Energies (Basel, Switzerland) in 2022.SDS of cas: 868-57-5 This article mentions the following:
This work aims to optimize the recovery of Me methacrylate (MMA) by depolymerization of polymethyl methacrylate (PMMA) dental resins fragments/residues. In order to pilot the experiments at tech. scale, the PMMA dental resins scraps were submitted by thermogravimetric anal. (TG/DTG/DTA). The experiments were conducted at 345, 405, and 420°C, atm. pressure, using a pilot scale reactor of 143 L. The liquid phase products obtained at 420°C, atm. pressure, were subjected to fractional distillation using a pilot scale column at 105°C. The physicochem. properties (d., kinematic viscosity, and refractive index) of reaction liquid products, obtained at 345°C, atm. pressure, were determined exptl. The compositional anal. of reaction liquid products at 345°C, 30, 40, 50, 60, 70, 80, and 110 min, at 405°C, 50, 70, and 130 min, and at 420°C, 40, 50, 80, 100, 110, and 130 min were determined by GC-MS. The morphol. of PMMA dental resins fragments before and after depolymerization was performed by SEM (SEM) and energy dispersive spectroscopy (EDX). The experiments show that liquid phase yields were 55.50%, 48.73%, and 48.20% (weight), at 345, 405, and 420°C, resp., showing a first order exponential decay behavior, decreasing with increasing temperature, while that of gas phase were 31.69%, 36.60%, and 40.13% (weight), resp., showing a first order exponential growth, increasing with temperature By comparing the d., kinematic viscosity, and refractive index of pure MMA at 20°C with those of liquid reaction products after distillation, one may compute percent errors of 1.41, 2.83, and 0.14%, resp. SEM anal. showed that all the polymeric material was carbonized. Oxygenated compounds including esters of carboxylic acids, alcs., ketones, and aromatics were detected by gas chromatog./mass spectrometry (GC-MS) in the liquid products at 345, 405, and 420°C, atm. pressure. By the depolymerization of PMMA dental resins scraps, concentrations of Me methacrylate between 83.454 and 98.975% (area.) were achieved. For all the depolymerization experiments, liquid phases with MMA purities above 98% (area.) were obtained between the time interval of 30 and 80 min. However, after 100 min, a sharp decline in the concentrations of Me methacrylate in the liquid phase was observed The optimum operating conditions to achieve high MMA concentrations, as well as elevated yields of liquid reaction products were 345°C and 80 min. In the experiment, the researchers used many compounds, for example, Methyl2-methylbutyrate (cas: 868-57-5SDS of cas: 868-57-5).
Methyl2-methylbutyrate (cas: 868-57-5) belongs to esters. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. Esters are more polar than ethers but less polar than alcohols. They participate in hydrogen bonds as hydrogen-bond acceptors, but cannot act as hydrogen-bond donors, unlike their parent alcohols. This ability to participate in hydrogen bonding confers some water-solubility.SDS of cas: 868-57-5
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Ester – an overview | ScienceDirect Topics