No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Ueber die Zerlegungsprodukte des Glyceryloxydes durch trockene Destillation
European Journal of Organic Chemistry
... The preparation of GLY in 1779 by Scheele, and his determination that it was susceptible to thermal decomposition during simple distillation [15][16][17][18][19] , predated even Wöhler's urea synthesis by half a century. By the mid-19 th century, acrolein 20 and acetic acid 21 had been identified as products of GLY decomposition. Wurtz synthesized PG in 1859, and determined that it could be oxidized to lactic acid in air in the presence of catalysts 22 . ...
... Aldehydes. An expansion of the aldehyde region of the 1 H NMR spectrum of an aerosol generated from PG/ GLY at 15 W, along with corresponding structure assignments, is shown in Fig. 5. Acrolein, compound 5, has long been known as a decomposition product of GLY 20 . In fact, it is the target molecule of the most common qualitative chemical test for the detection of GLY 19 . ...
Knowledge of the mechanism of formation, levels and toxicological profiles of the chemical products in the aerosols (i.e., vapor plus particulate phases) of e-cigarettes is needed in order to better inform basic research as well as the general public, regulators, and industry. To date, studies of e-cigarette emissions have mainly focused on chromatographic techniques for quantifying and comparing the levels of selected e-cigarette aerosol components to those found in traditional cigarettes. E-cigarettes heat and aerosolize the solvents propylene glycol (PG) and glycerol (GLY), thereby affording unique product profiles as compared to traditional cigarettes. The chemical literature strongly suggests that there should be more compounds produced by PG and GLY than have been reported in e-cigarette aerosols to date. Herein we report an extensive investigation of the products derived from vaporizing PG and GLY under mild, single puff conditions. This has led to the discovery of several new compounds produced under vaping conditions. Prior reports on e-cigarette toxin production have emphasized temperature as the primary variable in solvent degradation. In the current study, the molecular pathways leading to enhanced PG/GLY reactivity are described, along with the most impactful chemical conditions promoting byproduct production.
... The thermal degradation product of glycerin was characterized as an aldehyde by Berzelius (1839) [2], who named it acrolein, which is a contraction of 'acrid' (referring to its pungent smell) and 'oleum' (oil or oil-like consistency). Redtenbacher (1843) [3] then demonstrated that acrolein can be prepared from glycerin by distillation in the presence of dehydrating agents such as phosphorous pentoxide. He remarked that ,in a very highly diluted condition the smell [of acrolein] is not altogether unpleasant, being somewhat ethereal, but a few drops of acrolein brought into a room soon bring the company to tears' (quote from Roscoe and Schorlemmer's A Treatise on Chemistry [4]). ...
... The thermal degradation product of glycerin was characterized as an aldehyde by Berzelius (1839) [2], who named it acrolein, which is a contraction of 'acrid' (referring to its pungent smell) and 'oleum' (oil or oil-like consistency). Redtenbacher (1843) [3] then demonstrated that acrolein can be prepared from glycerin by distillation in the presence of dehydrating agents such as phosphorous pentoxide. He remarked that ,in a very highly diluted condition the smell [of acrolein] is not altogether unpleasant, being somewhat ethereal, but a few drops of acrolein brought into a room soon bring the company to tears' (quote from Roscoe and Schorlemmer's A Treatise on Chemistry [4]). ...
Acrolein (2-propenal) is ubiquitously present in (cooked) foods and in the environment. It is formed from carbohydrates, vegetable oils and animal fats, amino acids during heating of foods, and by combustion of petroleum fuels and biodiesel. Chemical reactions responsible for release of acrolein include heat-induced dehydration of glycerol, retro-aldol cleavage of dehydrated carbohydrates, lipid peroxidation of polyunsaturated fatty acids, and Strecker degradation of methionine and threonine. Smoking of tobacco products equals or exceeds the total human exposure to acrolein from all other sources. The main endogenous sources of acrolein are myeloperoxidase-mediated degradation of threonine and amine oxidase-mediated degradation of spermine and spermidine, which may constitute a significant source of acrolein in situations of oxidative stress and inflammation. Acrolein is metabolized by conjugation with glutathione and excreted in the urine as mercapturic acid metabolites. Acrolein forms Michael adducts with ascorbic acid in vitro, but the biological relevance of this reaction is not clear. The biological effects of acrolein are a consequence of its reactivity towards biological nucleophiles such as guanine in DNA and cysteine, lysine, histidine, and arginine residues in critical regions of nuclear factors, proteases, and other proteins. Acrolein adduction disrupts the function of these biomacromolecules which may result in mutations, altered gene transcription, and modulation of apoptosis.
... Despite the extensive research and knowledge gained in the field of biomaterials, optimal biomaterials specifically designed for dentistry applications are yet to be developed. In 1843, Redtenbacher introduced polymethyl methacrylate (PMMA), a polymer originated from acrylic acid with an odourless nature [1]. PMMA has undergone gradual enhancements over several decades, becoming increasingly refined for biomedical applications. ...
Composites play a pivotal role in a myriad of industries, including aerospace, automotive, household, marine, and medical sectors. The continual refinement of composite synthesis is paramount for optimizing their mechanical and physical attributes. This study explores the specific realm of dental applications, investigating the influence of calcite-zincate nanoparticles (CZNPs) at concentrations of 0, 0.2, 0.6, and 1.0% within Poly Methyl Methacrylate (PMMA) resin. Additionally, this research considers the synergistic effects of calcium carbonate, calcite, and zinc oxide in conjunction with CZNPs. The primary objective is a comprehensive assessment of mechanical properties, specifically focusing on flexural strength, tensile strength, and impact strength. Specimens are compared both with and without calcite-zincate nanoparticles, employing the open die method for self-polymerizing PMMA. Subsequently, detailed examination was carried out using scanning electron microscopy (SEM) to provide microscopic insights into the material's structure and composition. The outcomes of this research reveal a notable improvement in mechanical properties for specimens incorporating calcite-zincate nanoparticles (CZNPs) compared to those devoid of such reinforcement. Flexural strength, tensile strength, and impact strength are observed to be positively affected by CZNPs. This enhancement positions the composite as a promising option for applications in tooth restoration and prosthetics within the field of dentistry, showcasing the potential practical significance of incorporating CZNPs in PMMA resin formulations.
... PMMA was first discovered as an indistinguishable polymer foracrylic acid by Redtenbacher in 1843. The IUPAC name of this substance is Poly(methyl 2-methyl propanoate) [55]. As shown in Fig. 2, it is an artificial, linear copolymer formed by free radical polymerization of a monomer called methyl methacrylate (MMA) (C 5 H 8 O 2 ) and converted to poly(methyl methacrylate) (C 5 H 8 O 2 ) n . ...
In recent years, the optical capabilities of polymer composites have dominated the marketplace for applications in optoelectronic and energy devices. Supercapacitors, light-emitting displays, optical waveguide sensors, and organic photovoltaic cells are a few examples of the applications of the optical behavior of composites. Polymer composites are composed of nano/micro-sized inorganic particles (such as semiconductors, metal complexes, and synthetic nanoparticles) that are distributed within a polymer matrix. These materials have a significant role because they combine the optical properties of inorganic materials with the ease of processing of polymers, which utilizes the potential and performance of polymer-based optical systems. Optical features of polymer composites, such as indices of refraction, transparency, dispersion, and coefficients of absorption, influence their potential uses in optical systems and devices. The purpose of this research is to establish more insight into the optical characteristics of polymer composites and to understand the correlations between the structure and optoelectronic behavior of polymer composites. This review involves general concepts, scientific guidelines, and feasible mathematical sections. The unique optical characteristics of some common polymers (PEO, PMMA, PVA, and CS) and polymer composites are briefly reviewed. This review article establishes the fact that metal complexes are excellent over ceramic filler or nano-particles to improve optical absorption and decrease the optical band gap. An inspection of the fundamentals of light-matter interaction, ranging from classical (Drude-Lorentz model) to quantum methods for studying electron transition was exhibited. Furthermore, the applications of Tauc’s model and optical dielectric loss parameters to estimate the optical energy band gap of polymer composites are explained. Other fundamental optical parameters, such as absorption coefficient, optical dielectric constant, and refractive index are also explored. Finally, the Wemple-DiDomenico (WD) model is applied to investigate; the refractive index, optical dielectric constant, and optical spectra moments. The correlations between the optical dielectric function and several parameters such as ε∞, τ, N/m*, µopt, ρopt, ωp, and Eg are derived. Various models based on refractive index and absorption coefficient are discussed in detail to estimate crucial optical parameters.
... [2][3][4][5] PMMA is an odorless polymer of acrylic acid that was reported for the first time by Redtenbacher in 1843. 6 However, the development of PMMA for biomedical applications was a gradual process that took decades. This polymer's popularity for dental applications has increased since its introduction in 1937 in Philadelphia by Walter Wright and Vernon Brothers, 7 due to its unique properties, such as aesthetics, cost-effectiveness, fit accuracy, low density, and easy manipulation. ...
Objectives: To produce a systematic review regarding the effect of graphene-reinforced
polymethylmethacrylate used in dentistry on mechanical properties.
Methods: Electronic databases (Pubmed/MEDLINE, Web of Science, Embase) were independently searched by two researchers for relevant studies published up to December 2021.
An additional manual search was performed to identify relevant publications. The population,
intervention, comparison, and outcome (PICO) question was “In dentistry, does graphene-reinforced polymethylmethacrylate offer better mechanical properties than conventional
polymethylmethacrylate?”. The selection of articles was carried out according to the established inclusion and exclusion criteria, following the PRISMA flowchart. The inter-investigator reliability was assessed by Cohen’s Kappa coefficient. The risk of bias was assessed using
the Joanna Briggs Institute Critical Appraisal Checklist for Quasi-experimental Studies.
Results: Six in vitro studies were included in the qualitative analysis. A total of 247 specimens
were evaluated: 81 made of non-reinforced PMMA resin and 166 of PMMA reinforced with
graphene. The mechanical properties evaluated were flexural strength, flexural modulus, hardness, biaxial flexural strength, and impact strength. These properties seem to improve with the
addition of graphene in certain concentrations. The analysis of the risk of bias showed low risk.
Conclusions: Within the limitation of this study, graphene seems to strengthen some mechanical properties of PMMA dental resin. However, more studies are needed to understand
the ideal graphene concentration to improve resin’s clinical performance.
... Previous studies have investigated light-cured PMMA for denture repair and reported several benefits, such as ease of manipulation, controlled polymerization time, no monomer issues, and better mechanical properties [93,183,184]. The repair strength of light-cured PMMA (40)(41)(42)(43)(44) is remarkably superior compared to heat-cured (21-34 MPa) and cold-cured (~13MPa) PMMA materials [185]. In addition to the types of PMMA, various surface treatments, such as airborne abrasion using alumina particles, laser treatment [186], mechanical grinding with a bur [187], and immersion in a monomer solution [188][189][190] or organic solvents [191], may affect the repair strength of dentures. ...
A wide range of polymers are commonly used for various applications in prosthodontics. Polymethyl methacrylate (PMMA) is commonly used for prosthetic dental applications, including the fabrication of artificial teeth, denture bases, dentures, obturators, orthodontic retainers, temporary or provisional crowns, and for the repair of dental prostheses. Additional dental applications of PMMA include occlusal splints, printed or milled casts, dies for treatment planning, and the embedding of tooth specimens for research purposes. The unique properties of PMMA, such as its low density, aesthetics, cost-effectiveness, ease of manipulation, and tailorable physical and mechanical properties, make it a suitable and popular biomaterial for these dental applications. To further improve the properties (thermal properties, water sorption, solubility, impact strength, flexural strength) of PMMA, several chemical modifications and mechanical reinforcement techniques using various types of fibers, nanoparticles, and nanotubes have been reported recently. The present article comprehensively reviews various aspects and properties of PMMA biomaterials, mainly for prosthodontic applications. In addition, recent updates and modifications to enhance the physical and mechanical properties of PMMA are also discussed.
... The situation was somewhat improved with the comparatively recent introduction of semisynthetic (chemically modified natural) polymers, such as nitrocellulose in 1846 [1,2]. The first purely synthetic (as opposed to chemically modified natural) polymers recorded in the scientific literature, including polyacrolein and poly(acrylic acid) [3], and polystyrene [4], were obtained in the same period (the 1840s) by accident, e.g., as side products of chemical transformations or by the unintentional thermal or photochemical polymerization of the pure monomers. It is interesting to note that even in the early report describing the polymerization of styrene, it was recognized that the polymeric product (dubbed "metastyrole"), might find useful applications in the field of optics due to its ability to strongly refract light [4]. ...
... The availability of glycerol as a by-product of biodiesel production has led to an interesting possibility of using it as a renewable non-toxic raw material for production of 3HPA through a dehydration step (Johnson and Taconi, 2007). However, thermal dehydration of glycerol yields the highly toxic acrolein, which upon hydration in presence of sulfuric acid gives 3HPA (Pressman and Lucas, 1942;Redtenbacher, 1843). Several anaerobic microorganisms produce 3HPA by selective dehydration of glycerol in a single reaction step catalyzed by glycerol/diol dehydratase under mild environmental conditions. ...
... 3HPA can be efficiently produced from renewable glycerol via chemical or biotechnological means. Chemically, glycerol is initially thermally dehydrated to acrolein which upon rehydration in presence of sulphuric acid yields 3HPA [115,116]. However, acrolein is a highly toxic and explosive compound, the process requires harsh conditions of temperature and pH, and large amounts of gypsum are accumulated during the neutralization of the sulphuric acid with calcium salts. ...
A shift from fossil- to renewable biomass feedstock for the emerging bio-based economy requires the development and adoption of new sustainable technologies that are more suited for transformation of biomass components to chemicals, materials and energy. This thesis presents investigations on the development of processes based on industrial biotechnology as a key element for the production of chemicals from agro-/industrial by-products. The chemicals of interest are the ones that could potentially serve as building blocks, platforms, for other chemicals and polymers. Glycerol, a by-product of biodiesel production, was used as a raw material for the production of propionic acid, 3-hydroxypropionaldehyde (3HPA) and 3-hydroxypropionic acid (3HP), while methacrylic acid (MA) was produced from 2-methyl-1,3-propanediol, a by-product of butanediol production. Different strategies to overcome the bottlenecks such as product inhibition existing in the bioprocesses for production of the chemicals were studied.
Fermentation of glycerol to propionic acid was studied using Propionibacterium acidipropionici. High cell density cultivations were used to overcome the low production rate caused by slow microbial growth and product-mediated toxicity. Increasing the cell density by immobilization and sequential batch recycling improved the production rates by 2- and 6-fold, respectively, over that obtained using conventional batch. Potato juice, a by-product of potato starch processing, was shown to be a promising, inexpensive nitrogen/vitamin source for the growth of the organism and propionic acid production.
Lactobacillus reuteri was employed as a whole cell biocatalyst for the conversion of glycerol to 3HPA and 3HP in aqueous solution. Production of 3HPA using glycerol dehydratase activity of the cells, limited by substrate inhibition and product toxicity, was performed in a fed-batch mode with in situ complexation of the hydroxyaldehyde with bisulfite, and subsequent removal through binding to an anion exchanger. This resulted in increase in production of 3HPA from 0.45 g/g biocatalyst in a batch process to 5.4 g/g in the developed process.
3HP is formed as an oxidation product of 3HPA, however its accumulation as a product of glycerol metabolism in wild-type L. reuteri has not been reported earlier. The metabolic fluxes through the glycerol reductive and oxidative pathways were calculated using variable volume fed-batch operation. The glycerol feeding strategies were optimized to yield complete conversion of 3HPA into equimolar mixture of 3HP and 1,3PDO.
MA was quantitatively produced at high purity from 2-methyl-1,3-propanediol by a novel process involving integrated biological and chemical catalysis. Whole resting cells of Gluconobacter oxydans were used for selective oxidation of the substrate to the corresponding hydroxycarboxylic acid, which upon dehydration over TiO2 at 210 oC yielded MA. This process offers a potential, significantly greener alternative to the acetone-cyanohydrin process used for MA production, involving highly toxic substrates, large amounts of waste and greenhouse gas emissions.
... 3-Hydroxypropionaldehyde (3HPA), a b-hydroxyaldehyde, is an important specialty chemical and a potential precursor for a variety of chemicals including 1,3-propanediol (1,3PDO), 3-hydroxypropionic acid (3HP), acrylic acid, etc. (Redtenbacher, 1843;Voisenet, 1914). No industrial process for production of 3HPA has yet been established. ...
3-Hydroxypropionaldehyde (3HPA) is an important specialty chemical which can be produced from glycerol using resting cells of Lactobacillus reuteri. This biocatalytic route, however, suffers from substrate- and product-mediated loss of enzyme activity within 2 h of biotransformation. In order to overcome the inhibitory effects of 3HPA, complex formation with sodium bisulfite was investigated, optimized and applied for in situ capture of the aldehyde during biotransformation of glycerol in a fed-batch process. As a result, the activity of the cells was maintained for at least 18 h. The 3HPA produced per gram cell dry weight was increased 5.7 times compared to the batch production process, and 2.2 times compared to fed-batch process without in situ complex formation. This approach may have potential for production and in situ removal of 3HPA after further process development. Biotechnol. Bioeng. © 2012 Wiley Periodicals, Inc.
Background:
Polymethyl methacrylate (PMMA) membranes are increasingly recognized for their effectiveness in treating acute kidney injury (AKI) due to their strong adsorption capabilities, particularly for inflammatory mediators like β2-microglobulin and IL-6. These membranes ensure mechanical stability and chemical inertness, minimizing adverse reactions during blood filtration.
Summary:
In acute conditions such as sepsis and acute respiratory distress syndrome (ARDS), PMMA membranes show promising findings. In sepsis, they may help reduce multiorgan failure by modulating immune responses, although further research is needed to confirm their routine use. For ARDS, PMMA membranes could mitigate "cytokine storms" by adsorbing key cytokines, improving oxygenation and hemodynamic stability, which may reduce ICU stays and reliance on mechanical ventilation. Monitoring biomarkers like IL-6, TNF-α is critical for tracking efficacy and tailoring therapy to individual needs. In chronic conditions, such as hemodialysis for chronic kidney disease, PMMA membranes help lower oxidative stress and β2-microglobulin levels, reducing complications such as amyloidosis. By decreasing oxidative damage, they provide long-term protective benefits for dialysis patients.
Key message:
While these advantages are notable, large-scale studies are needed to establish PMMA's efficacy, refine treatment protocols, and confirm its broader role in acute and chronic disease management. The potential of PMMA membranes highlights their value, but standardized clinical evidence is necessary for widespread adoption.
Abstract
Keywords: Polymethylmethacrylate; Chemical Polishing; Mechanical Polishing; Chemical Polishing and Microwaving; Brushing Simulator;
Surface Roughness; Weight Loss
Objectives:
• To determine and compare the surface roughness of heat and chemically cured acrylic resins after subjecting them to mechanical
polishing, chemical polishing and chemical polishing with microwaving.
• To find out the surface roughness and weight loss caused by tooth brushes and dentifrices on heat and chemically cured acrylic
resins which were subjected to mechanical polishing, chemical polishing and chemical polishing with microwaving.
Materials and Methods: Rectangular specimens were prepared and they were subjected to mechanical polishing, chemical polishing
and chemical polishing with microwaving. These specimens were then subjected to tooth brushing with tooth pastes. Surface
roughness and weight of the specimens were measured before and after tooth brushing. Medium and hard tooth brushes and one
regular tooth paste and one gel tooth paste were included. Brushing was done with a motor driven device and the brushing cycles
were limited to 30,000. Data was statistically analyzed using ANOVA.
Conclusions
• Heat cure acrylic resin can resist surface roughness better than self cure resins. The roughness values observed in both the resins
were within the clinically acceptable limits.
• Heat cure resin which is mechanically polished can resist surface roughness better than in chemically polished specimens.
• Tooth brushes and pastes included in the study will not cause surface roughness beyond the acceptable limit within a period of
three years.
• Heat cure acrylic resin undergoes more weight loss than self cure resin when subjected to brushing with tooth pastes.
• Microwaving did not particularly improve the properties of the resins to resist surface roughness and weight loss.
The global acrylate monomers market is projected to reach approximately USD 12 billion by the year 2027. The rapid growth is based on the broad range of application of acrylates from routine household uses and cosmetics/personal care to industrial and surgical/dental applications. With the steep increase in volume and broad use of these products comes increased likelihood of exposure and the potential for adverse effects. Hence, this chapter focuses mainly on the hazard profiles, potential exposure scenarios, and exposure control measures for the various chemical classes of these acrylates. Each section within this chapter integrates scientific, regulatory, and epidemiological information collected from publicly available peer‐reviewed publications and databases maintained by recognized regulatory agencies in various jurisdictions.
The dehydration of lactic acid to produce acrylic acid is a renewable alternative to the mostly used production of acrylic acid from propene. In this review, the recent developments and state of the art for the dehydration of lactic acid to acrylic acid are presented and critically commented. The most recent publications on the topic are discussed inetail with respect to the observed catalysts and process performance data. Among the different catalysts developed, three main groups can be distinguished: zeolites, sulphates, and phosphates. The latter, especially hydroxyapatites, have recently attracted the attention of academics in particular. The three families of catalysts are discussed and the recent developments and technical drawbacks in the gas phase dehydration are reported.
Ethyl vinyl ether
Benzyltriethylammonium chloride
1, 1‐Dichloro‐2‐ethoxycyclopropane
Copper sulfate pentahydrate
The article contains sections titled: 1.
Introduction
2.
Properties
2.1.
Physical Properties
2.2.
Chemical Properties
3.
Production
3.1.
Acrolein by Propene Oxidation
3.2.
Methacrolein
4.
Quality and Analysis
5.
Handling, Storage, and Transportation
6.
Uses and Production Data
7.
Toxicology and Ecotoxicology
7.1.
Toxicology
7.2.
Ecotoxicology
Acrolein is the simplest unsaturated aldehyde. It is an important intermediate in the production processes of a variety of substances. The main use of isolated acrolein is in the production of d,l ‐methionin, but in far more production processes, acrolein is used without purification. Acrolein is an extremely reactive chemical and, in very low concentrations, acts as a very effective broad‐spectrum biocide. Methacrolein is produced commercially as an organic intermediate, which is used as building block for chain expansions or, in limited application, in the synthesis of flavors and fragrances.
Marked retardation of growth of lymphosarcoma implants was observed in pyridoxine-deficient rats injected with 2 mg daily of cortisone or of methyl testosterone. Survival of pyridoxine-dencient, tumor-bearing rats was prolonged by testosterone and shortened by cortisone.
885 -848 -8 4 8 -840 nach MeerretLig. Die Analysen gaben 49,3, 49,4, 49,7 pCt. Kohlenstoff und eine wechselnde Menge Wasserstof
- Wasserfreie
Wasserfreie S u r e. 885 -848 -8 4 8 -840 nach MeerretLig. Die Analysen gaben 49,3, 49,4, 49,7 pCt. Kohlenstoff und eine wechselnde Menge Wasserstof. D i e m Kuhlenstoffgehalt kommt dem des Ameisenathers sehr nahe,