Production of Aromatic Compounds from Crude Carotene Extract of Carrots by Thermal Degradation: A Preliminary Study

2021 ◽  
Vol 21 (1) ◽  
pp. 163-168
Author(s):  
Daimon Syukri ◽  
Rini . ◽  
Wellyalina . ◽  
Nika Rahma Yant ◽  
Jaswandi .
Keyword(s):  
Thermal Degradation ◽  
Aromatic Compounds ◽  
Preliminary Study

Thermal-Degradation of Polymers and Polymer Models. V. A Model for Copoly(styrene-methyl methacrylate)

1990 ◽  
Vol 43 (3) ◽  
pp. 521 ◽  
Author(s):  
GD Fallon ◽  
KA Holland ◽  
ID Rae
Keyword(s):  
Thermal Degradation ◽  
Methyl Methacrylate ◽  
Aromatic Compounds ◽  
Chain Termination ◽  
Homolytic Cleavage ◽  
X Ray ◽  
Polymer Models ◽  
Rate Study ◽  
Normal Bond ◽  
Comparative Rate

The synthesis of (�)- and meso-dimethyl 2,3-dimethyl-2,3-bis(2′-methyl-2′-phenylpropyl)butane-dioate from methyl 2,4-dimethyl-4-phenylpentanoate , via a silyl enol acetal, is described. The X-ray structure of the meso isomer shows serious distortions from normal bond lengths and angles, most notably a length of 162.7(4) pm for the crowded central C-C bond. The compounds were synthesized as models for head-to-head units which might form by chain termination through dimerization of macroradicals during copolymerization of styrene and methyl methacrylate . Thermal degradation of the diphenyl -substituted diesters at 210° gave products which may have formed by plausible routes from radicals resulting from homolytic cleavage of the crowded C-C bond. Inclusion of the phenyl groups makes the molecules more crowded than the corresponding tetraesters which were reported earlier, and a comparative rate study shows that the aromatic compounds are less stable to heat as a result of the penultimate effects of greater crowding at carbons which are β to the thermally vulnerable bond.

scholarly journals Thermal pyrolysis of LDPE and LLDPE films in post-consumer packaging

2020 ◽  
Vol 24 ◽  
pp. e23
Author(s):  
Douglas Da Silva Vallada ◽  
Carlos Alberto Mendes Moraes ◽  
Paulo Ricardo Santos da Silva
Keyword(s):  
Infrared Spectroscopy ◽  
Chemical Composition ◽  
Thermal Degradation ◽  
Aromatic Compounds ◽  
Petrochemical Industry ◽  
Plastic Waste ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Worldwide Production ◽  
The One

Thermoplastics are increasingly present in the daily life of society in the most varied applications. Among the thermoplastics, polyethylene is the one that presents the higher volume of worldwide production and consumption. However, a large part of its applications are for products with a short shelf life, especially the food packaging sector. This way, they become expressive constituents in the composition of urban solid waste, leading to large quantities often being deposited in landfills. Pyrolysis appears as a technology for recycling plastic waste, allowing the recovery of the monomers that originated it. Through this thermochemical process, the waste is converted into three different products: oil or, in some cases wax, non-condensable gases, and a solid fraction named char. Thus, the goal of this study is to contribute for the development of pyrolysis as a technology for the final treatment of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) waste from post-consumer packaging, through the analysis of the influence of the pyrolysis temperature in the chemical composition of the oil produced, as well as the discussion of possible applications. For this purpose, the waste was initially characterized through analyses of attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), thermogravimetry (TGA), differential scanning calorimetry (DSC), and X-ray fluorescence (XRF). The characterization experiments showed that the plastic waste is constituted of 4.07% ash, 0.52% fixed carbon, and 95.54% volatile matter, showing its great potential to produce pyrolytic oil. Thermal degradation of the waste initiated at around 410°C and continued through about 530°C, with maximum rate of thermal degradation at about 488°C. The pyrolysis process was carried out with 50g samples of post-consumer LDPE and LLDPE, previously agglutinated, with particle size ranging from 0.001mm to 4mm, in a horizontal quartz reactor, with an inert atmosphere of N2, heating rate of 10°C/min, and residence time of 30 minutes. The experiments were conducted with experimental temperatures of 500°C and 700°C, in order to verify the influence of the temperature in the chemical composition of the oil obtained in the process. The analysis of the oil collected at 500°C by infrared spectroscopy revealed a specter similar to the one of commercial diesel. Through gas chromatography coupled with mass spectrometry, it was verified a composition constituted mostly by olefins (44%), from 8 to 35 carbon atoms, followed by paraffins (23.8%), and cycloparaffins (10%). There was also a considerable percentage of alpha-olefins, important for the petrochemical industry, and a percentage of aromatic compounds on a trace level. By varying the temperature to 700°C, an increase in the level of aromatic compounds to 16.6% occurred, accompanied by a decrease in the percentage of olefins, paraffins, and cycloparaffins. The oils obtained in both temperatures have potential for application in steam cracking or conventional catalytic cracking processes to obtain the raw materials of the petrochemical industry.

scholarly journals Effect of Degradation Time on Carotene Content in Crude Carotene Extract of Carrot for the Formation of its Derivative Aromatic Compounds

2021 ◽  
Author(s):  
Daimon Syukri ◽  
Rini . ◽  
Wellyalina . ◽  
Nika Rahma Yanti ◽  
Jaswandi .
Keyword(s):  
Thermal Degradation ◽  
Aromatic Compounds ◽  
Oxygen Supply ◽  
Degradation Process ◽  
Carotene Content ◽  
Thermal Degradation Process ◽  
The Difference ◽  
Degradation Time ◽  
Carotene Degradation

Background: The difference in degradation time on the formation of carotene’s derivative aromatic compounds [β-ionone and dihydroactinidiolide (dhA)] due to thermal degradation process of carotenes in crude carotenoid extract of carrot was studied. Methods: β-ionone and dhA formation and that of carotenes degradation during thermal degradation (T=140°C) was observed periodically for 4 h. The constant oxygen supply during degradation was maintained at approx. 7 L/h. Result: The formation of β-ionone and dhA accumulated significantly with increasing duration of the degradation process. The maximum formation of β-ionone and dhA could be estimated with the pattern of carotenes degradation. After 4 h of degradation, more than 80% carotene has degraded. It can be concluded that the degradation process of crude carotene extract from carrots at temperature of 140°C will result in a maximum carotene degradation process when the degradation process is carried out for 5 h.

scholarly journals A Preliminary Study on the Newly Isolated High Laccase-producing Fungi: Screening, Strain Characteristics and Induction of Laccase Production

2018 ◽  
Vol 13 (1) ◽  
pp. 463-469
Author(s):  
Qian Wang ◽  
Yingying Qian ◽  
Yuhan Ma ◽  
Changwei Zhu
Keyword(s):  
Aromatic Compounds ◽  
Culture Medium ◽  
Laccase Activity ◽  
Laccase Production ◽  
Control Group ◽  
Dependent Manner ◽  
Plant Materials ◽  
Its Sequence Analysis ◽  
Preliminary Study ◽  
Dose Dependent

AbstractA simple separation method was used in this study to directly separate laccase-producing fungi from withered plant materials. A laccase-producing filamentous fungus was isolated and purified. The strain was highly similar to the species in genus Trametes by ITS sequence analysis, and therefore named Trametes sp. MA-X01. The addition of cupric ions and aromatic compounds to the liquid medium could induce the laccase synthesis in Trametes sp. MA-X01. Copper-induced laccase activity increased in a dose-dependent manner. The highest laccase activity (2138.9 ± 340.2 U/L) was obtained by adding 2.5 mM Cu2+ to the culture medium, which was about 7 times higher than that of the control group. The induction degree of aromatic compounds was different. For the present study, the highest laccase activities were obtained by adding vanillic acid (1007.9±59.5 U/L) or vanillin (981.6±77.2 U/L) to the medium, which were 3.5 and 3.4 times higher than the laccase activity of the control group, respectively.

Mechanism of thermal degradation of sucrose. A preliminary study

1978 ◽  
Vol 31 (8) ◽  
pp. 1825 ◽  
Author(s):  
GN Richards ◽  
F Shafizadeh
Keyword(s):  
Thermal Decomposition ◽  
Thermal Degradation ◽  
First Order ◽  
Preliminary Study

Evidence is presented which indicates that the initiating reaction in the thermal decomposition of sucrose is a first-order intramolecular displacement yielding D-glucose and a fructose derivative(F*) (anhydride?). The latter product has not yet been identified, but is postulated as reacting rapidly with sucrose to yield trisaccharides of the type F2G. When another alcohol (erythritol) is present in the melt, F* reacts with it to produce fructoside(s).

The Ultrastructure of Metastatic Human Mammary Carcinoma After Prolonged Estrogen Therapy

1967 ◽  
Vol 25 ◽  
pp. 180-181
Author(s):  
John H.L. Watson ◽  
John L. Swedo ◽  
R.W. Talley
Keyword(s):  
Mammary Carcinoma ◽  
Osmium Tetroxide ◽  
Estrogen Therapy ◽  
Ultrastructural Level ◽  
Uranyl Acetate ◽  
Human Mammary Carcinoma ◽  
Surgical Biopsy ◽  
Lead Hydroxide ◽  
Preliminary Study ◽  
Hormonal Therapies

A preliminary study of human mammary carcinoma on the ultrastructural level is reported for a metastatic, subcutaneous nodule, obtained as a surgical biopsy. The patient's tumor had responded favorably to a series of hormonal therapies, including androgens, estrogens, progestins, and corticoids for recurring nodules over eight years. The pertinent nodule was removed from the region of the gluteal maximus, two weeks following stilbestrol therapy. It was about 1.5 cms in diameter, and was located within the dermis. Pieces from it were fixed immediately in cold fixatives: phosphate buffered osmium tetroxide, glutaraldehyde, and paraformaldehyde. Embedment in each case was in Vestopal W. Contrasting was done with combinations of uranyl acetate and lead hydroxide.

Fine structure of early degenerating myofibers in the tibialis anterior of young ‘MDX’ mouse

1988 ◽  
Vol 46 ◽  
pp. 322-323
Author(s):  
H.D. Geissinger ◽  
C.K. McDonald-Taylor
Keyword(s):  
Fine Structure ◽  
Muscle Regeneration ◽  
Tibialis Anterior ◽  
Genetic Defect ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Histopathological Changes ◽  
Electron Microscopic ◽  
Dystrophic Mouse ◽  
Preliminary Study

A new strain of mice, which had arisen by mutation from a dystrophic mouse colony was designated ‘mdx’, because the genetic defect, which manifests itself in brief periods of muscle destruction followed by episodes of muscle regeneration appears to be X-linked. Further studies of histopathological changes in muscle from ‘mdx’ mice at the light microscopic or electron microscopic levels have been published, but only one preliminary study has been on the tibialis anterior (TA) of ‘mdx’ mice less than four weeks old. Lesions in the ‘mdx’ mice vary between different muscles, and centronucleation of fibers in all muscles studied so far appears to be especially prominent in older mice. Lesions in young ‘mdx’ mice have not been studied extensively, and the results appear to be at variance with one another. The degenerative and regenerative aspects of the lesions in the TA of 23 to 26-day-old ‘mdx’ mice appear to vary quantitatively.

Sign in / Sign up

Export Citation Format

Share Document