• 공업화학
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• 제30권6호
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• pp.707-711
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• 2019

The feasibility of waste concrete as a catalyst for the effective pyrolysis of polyethylene terephthalate (PET) was examined using thermogravimetric (TG) and pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS) analyses. TG analysis results indicated that the maximum decomposition temperature of PET is not altered by the use of waste concrete, showing similar values (407 ℃ and 408 ℃ at 5 ℃/min). Meanwhile, the volatile product distribution data obtained from the Py-GC/MS analysis revealed that the use of waste concrete promoted the deoxygenation reaction via converting the oxygen containing products such as benzoic acids, benzoates, and terephthalates to valuable deoxygenated aromatic hydrocarbons including benzene, toluene, ethylbenzene, and styrene. This suggests that the waste concrete can be used as a potential catalyst for the production of valuable aromatic hydrocarbons from PET pyrolysis.

• Elastomers and Composites
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• 제55권4호
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• pp.257-262
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• 2020

Vehicle wiper blades are typically treated with chlorine to lower their friction coefficient with the windshield surface. In this study, a chlorinated, natural rubber (NR) vehicle wiper blade was characterized using a pyrolytic technique. Unchlorinated and chlorinated wiper blades were pyrolyzed and the pyrolysis products were analyzed using gas chromatography/mass spectrometry (GC/MS). Besides isoprene and dipentene, the other principal pyrolysis products such as 1,5,8-p-menthatriene (MTT) and p,α-dimethylstyrene (DMS) were observed. The MTT and DMS ratios did not vary for the chlorinated nor unchlorinated samples when the entire rubber lip of the wiper blade was pyrolyzed. However, when only the lip surface of the wiper blade rubber was pyrolyzed (via scratching with a knife) the relative ratios of the chlorinated sample were much greater than those of the unchlorinated sample. As MTT is produced from the conjugated backbone of chlorinated NR that forms through HCl elimination during initial pyrolysis, and DMS is generated by the dehydrogenation of MTT, these two products could be used as markers for detecting chlorinated NR.

• 보존과학회지
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• 제36권2호
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• pp.103-111
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• 2020

건조칠기 유물 세척 시 사용되는 다양한 용매을 대상으로 클리닝 효과를 비교하기 위해 실험을 진행하였다. 건조칠과 자외선에 24일 노출시킨 건조칠에 물, 에탄올, 아세톤, 헥산을 가하여 녹아 나오는 물질을 열분해/GC/MS로 검출하였다. 용출되는 양은 아세톤과 에탄올에서 많았으며, 극성이 높은 용매인 물은 저분자량 용출에 비교적 효율이 좋았다. 비극성 용매인 헥산은 용출량이 매우 낮았다. UV에 24일 노출되어 열화가 많이 진행된 건조칠은 노출되기 전 건조칠에 비해 용출되는 물질이 크게 증가하였다. 열화가 되면서 고분자 형태의 우루시올 사슬이 절단되고 산화되는 과정을 거쳐 dicarboxylic acid를 포함한 저분자량의 극성 물질을 생성하기 때문인 것으로 보인다. 이와 같은 용출특성은 칠기유물을 클리닝하는 용매를 선택할 때 유물의 열화 상태와 더불어 중요한 참고자료가 될 것이다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
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• pp.173-176
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• 2006

Pyrolysis-gas chromatography (Py-GC) in the presence of organic alkali of tetrabutylammonium hydroxide (TBAH) was applied to characterize the polyphenol fragments with a carbonyl group causing different magnitude of photo-yellowing in chemithermomechanical pulp (CTMP) papers. Two different origin of CTMP papers prepared from different individuals of Eucalyptus globulus trees showing high and low yellowing after photo-irradiation was compared before photo-irradiation. As a result, 7 peaks assigned to a series of phenol compounds with a carbonyl group, derived mainly from lignin, gave significant amount of phenol compounds with a carbonyl group for the paper sample of latent high yellowing, i.e., butoxy-and syringaldehyde, butoxy-and syringylacetone, butoxy-acetoguaiacone, butoxy-acetosyringone, butoxy-acetoethylsyringone, 3-methoxy-4-butoxy butyl ester, and 3,5-dimethoxy-4-butoxy butyl ester, using Py-GC/mass spectrometry (MS). The Py-GC method combined with TBAH successfully characterized polyphenol fragments with a carbonyl group causing differ high photo-yellowing in CTMP papers using a microgram order of samples.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1276-1280
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• 2003

Thermal behavior of bromphenols was investigated by direct pyrolysis at high temperature. The thermal degradation products formed by the pyrolysis of mono-bromophenols (o-, m-, and p-) were identified by gas chromatography-mass spectrometry. During the pyrolysis reactions, several kinds of dioxins and furans were produced, and the relative ratio of pyro-products was dependent on the substituted position of bromine in phenolic structure due to the effect of symmetry and steric hindrance. The formation of dioxins can be explained by the phenoxy radical addition and Br atom elimination at an ortho-carbon site on phenolic structure. On the other hand, the formation of furans can be explained by the ortho-ortho carbon coupling of phenoxy radicals at unsubstituted sites to form o, o'-dihydroxydiphenyl intermediate via its keto-tautomer, followed by $H_2O$ elimination. The pyrolysis temperature has also a substantial effect on the dimerized products quantities but little effect on the type of pyro-products. Moreover, the formation mechanism of pyro-products was suggested on the basis of products identified.

• 한국연초학회지
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• 제4권2호
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• pp.63-66
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• 1982

Coumarin was pyrolyzed at $500^{\circ}C$ in a stream of nitrogen. The pyrolyzates of coumarin were adsorbed on the activated charcoal and then eluded by carbon disulfide. The eluted pyrolyzates were identified using a gas chromatography/mass spectrometry. Benzene, toluene, phenylacetylene, styrene, benzofuran and naphthalene were detected from the pyrolyzates of coumarin on the basis of their mass spectra. The pyrolytic mechanism of coumarin was also discussed.

• Journal of Biosystems Engineering
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• 제43권1호
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• pp.14-20
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• 2018

Purpose: The purpose of this study was to investigate the performance of a vacuum pyrolysis system, to analyze bio-oil characteristics, and to examine the applicability for farm-scale capacity. Methods: The biomass was pyrolyzed at 450, 480, and $490^{\circ}C$ on an electric heat plate in a vacuum reactor. The waste heat from the heat exchanger of the reactor was recycled to evaporate water from the bio-oil. The chemical composition of the bio-oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Results: According to the analysis, the moisture content (MC) in the bio-oil was approximately 9%, the high heating value (HHV) was approximately 26 MJ/kg, and 29 compounds were identified. These 29 compounds consisted of six series of carbohydrates, 17 series of lignins, and six series of resins. Conclusions: Owing to low water content and the oxygen content, the HHV of the bio-oil produced from the vacuum reactor was higher by about 6 MJ/kg than that of the bio-oil produced from a fluidized bed reactor.

• 한국지역사회생활과학회지
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• 제24권2호
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• pp.243-249
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• 2013

Identification of coating film species from ancient coating materials is needed to maintaine their surfaces without loss of their original beauty for a long time and understand the historical background of manufacturing techniques. A pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was applied to identify the origine of films in ancient coating materials. The pyrolysis products, which reflect the source from which they originate were detected distinctively at $500^{\circ}C$. This is a rapid technique that does not require large amounts of sample or any sample preparation. Sesquiterpenes are a class of terpenes that consist of three isoprene units were identified as cadienes, selinenes, cubebenes from the raw material of dendropanax morbifera. On the other hand, alkanes(tetra~heptadecanes), alkenes (tri~heptadecenes), allkyphenols, catechols and fatty acids were detected from the raw material of the lacquer film. Based on these results, the origine of historic coatings artifacts was identified using py-GC/MS by comparison with their pyrolysis products.

• 한국연초학회지
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• 제29권2호
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• pp.118-124
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• 2007

GRLs(Guidance Residue Levels) of agricultural chemicals for tobacco are recommended by the CORESTA Agro-Chemical Advisory Committee guide. In the GRLs list, organochlorine group is one of pesticides commonly used on tobacco cultivation. In this model study, the quantitative correlation in the transfer rate of pesticide residue into tobacco smoke by spiking of organochlorine pesticides to cigarette and pyrolysates were investigated. The spiking concentration referred to the range of GRLs list and the organochlorine pesticides in mainstream smoke were analyzed by GC-MS. For the understanding of the composition variation versus temperature, the behavior of pesticides was investigated by pyrolysis-gas chromatography-mass spectrometry(Py-GC-MS). In this study, the transfer rate of pesticide residue into tobacco smoke at four different spiking concentration and the composition of pyrolysates were analyzed differently. At $10\;{\mu}g/cig$ spiking concentrations, the organochlorine pesticides were transferred into tobacco smoke in $0.02\;{\sim}\;10.19\;%$ each of component and the most of pesticides were pyrolyzed during smoking. It was found that the decomposition compounds from organochlorine pesticides were mainly composed of oxygenated and nitrogenous compounds. This study could estimate that the transfer rate of pesticides into tobacco smoke is very small amount.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.547-552
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• 2007

This study examined the thermal reactions of 2,4-dibromophenol (diBP), 2,6-diBP and 2,4,6-triBP. The products obtained under pyrolytic conditions were analyzed by gas chromatography/mass spectrometry (GC/MS). 2,7-dibromodibenzo-p-dioxin (diBDD) was the major compound produced from the thermal reaction of 2,4-diBP. In addition, monoBDD and triBDDs were obtained through a process of debromination and bromination, respectively. The pyrolysis of 2,6-diBP and 2,4,6-triBP produced two major brominated dioxin isomers through direct condensation and a Smiles rearrangement. The two ortho-Brs in 2,6-diBP and 2,4,6-triBP mainly led to the production of dioxins, whereas in addition to 2,7-diBDD, 2,4-diBP produced two furans as minor products, 2,8-dibromodibenzofuran (diBDF) and 2,4,8-triBDF, through the intermediate dihydroxybiphenyl (DOHB). The maximum yield of the major dioxins was obtained at 400 oC, and decomposition by debromination at 500 oC resulted in less substituted bromodioxins.