• Title, Summary, Keyword: butadiene

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Theoretical Studies of Geometries of Hexafluoro-1,3-butadiene, Tetrafluoro-1,3-butadiene, and Difluoro-1,3-butadiene Compounds

  • Cho, Han-Gook;Kim, Kang-Woo;Cheong, Byeong-Seo
    • Bulletin of the Korean Chemical Society
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    • v.25 no.4
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    • pp.452-459
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    • 2004
  • The geometrical structures of various isomers of hexafluoro-1,3-butadiene (HFBD), tetrafluoro-1,3-butadiene (TFBD), and difluoro-1,3-butadiene (DFBD) have been studied theoretically. Natural steric and natural resonance theory (NRT) analyses indicate that the lower energy of skew s-cis conformer of hexafluoro-1,3-butadiene than that of the s-trans conformer is originated from the strong steric repulsions between fluorine atoms particularly in the s-trans conformer. The resonance structures generated by NRT also show that the lone electron pairs of fluorine atoms effectively extend the conjugation, and the large differences in energy among the structural isomers of tetrafluoro-1,3-butadiene and difluoro-1,3-butadiene are in part attributed to the differences in the delocalization energies, in addition to the steric repulsion between fluorine atoms. Other interatomic interactions, such as hydrogen bonding, also play important roles in determination of the structures of isomers of tetrafluoro-1,3-butadiene and difluoro-1,3-butadiene.

Effects of Inhibition on Formation and Growth of Polymer in Butadiene Extraction Unit (Butadiene Extraction Unit 내의 Polymer 생성 억제 효과)

  • Im, Gyeong
    • The Journal of Natural Sciences
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    • v.5 no.2
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    • pp.63-73
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    • 1992
  • There are many methods of obtaining butadiene described in the literature. In the america it is produced largely from petroleum gases, i.e., by catalytic dehydrogenation of butene of butene-butane mixtures. Butadiene can be recovered from the $C_4$ residue of an olefin plant by distilling off a fraction containing most of the butadiene, catalytically hydrogenating the higher acetylenes to olefins and separating the product from other olefins and isobutane by extraction. Also it can be obtained by cracking naphtha and light oil. Among the individual dienes of commercial importance, 1, 3-butadiene is of first importance. It is used primarily for the production of polymers.In the present paper, it was investigated for a effect of the formation and the growth inhibition of popped corn polymer in butadiene extraction unit. As a result of study, inhibitors, $NaNO_2$ and TBC were good effective for inhibition of the formation and growth in popcorn polymer. The rational formula of popcorn polymer obtained was $(C_4H_6)_x$.

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Effect of Butadiene in Catalytic Trimerization of Isobutene Using Commercial C4 Feeds

  • Yoon, Ji-Woong;Jhung, Sung-Hwa;Lee, Ji-Sun;Kim, Tae-Jin;Lee, Hee-Du;Chang, Jong-San
    • Bulletin of the Korean Chemical Society
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    • v.29 no.1
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    • pp.57-60
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    • 2008
  • Catalytic oligomerization of isobutene to produce triisobutenes has been performed over a cation-exchange resin (Amberlyst-35) by using commercial C4 feeds. The catalytic activity in the oligomerization was retained without deactivation up to 90 h of reaction in a simulated reaction feed without butadiene, but its activity was significantly affected by the presence of butadiene in commercial C4 feeds. The isobutene conversion with time-on-stream was significantly decreased in the presence of butadiene, indicating the catalyst deactivation by butadiene. However, the stable activity for trimerization was accomplished when the oligomerization was carried out after eliminating butadiene by hydrogenation of the feeds. This work demonstrates that butadiene plays a role as a catalyst poison on the solid acid catalyst, so that its removal in the reactant feed is essential for practical application of trimerization.

Composition-Dependent Properties of Natural Rubber Blended with Butadiene Rubber (배합비에 의한 고무 블렌드의 물성변화)

  • Kwon, Kih-Wan;Park, Moon-Soo
    • Elastomers and Composites
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    • v.31 no.5
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    • pp.347-352
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    • 1996
  • A natural rubber was blended with a butadiene rubber with different ratios. A natural rubber, along with three different blends, its ratio varying from 10 to 15 to 20 weight %, were prepared and tested. It was found that inclusion of the butadiene rubber increased cure time, compared to the natural rubber. It is speculated that increased free volume due to the inclusion of butadiene rubber contributed to this effect. Furthermore, inclusion of butadiene rubber led to increase hardness of a sphere, and as a result, the extent of rebound increased sharply.

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Comparison of SBR/BR Blend Compound and ESBR Copolymer Having Same Butadiene Contents

  • Hwang, Kiwon;Lee, Jongyeop;Kim, Woong;Ahn, Byungkyu;Mun, Hyunsung;Yu, Eunho;Kim, Donghyuk;Ryu, Gyeongchan;Kim, Wonho
    • Elastomers and Composites
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    • v.54 no.1
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    • pp.54-60
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    • 2019
  • The rapid development of the automobile industry is an important factor that led to the dramatic development of synthetic rubber. The tread part of tire that comes in direct contact with the road surface is related to the service life of the tire. Rubber compounds used in tire treads are often blended with SBR (styrene-butadiene rubber) and BR (butadiene rubber) to satisfy physical property requirements. However, when two or more kinds of rubber are blended, phase separation and silica dispersion problems may occur due to non-uniform mixing of the rubber. Therefore, in this study, we synthesized an SBR copolymer with the same composition as that of a typical SBR/BR blend compound by controlling butadiene content during ESBR (emulsion styrene-butadiene rubber) synthesis. Subsequently, silica filled compounds were manufactured using the synthesized ESBR, and their mechanical properties, dynamic viscoelasticity, and crosslinking density were compared with those of the SBR/BR blended compound. When the content of butadiene was increased in the silica filled compound, the cure rate accelerated due to an increased number of allylic positions, which typically exhibit higher reactivity. However, the T-2 compound with increased butadiene content by synthesis less likely to show an increase in crosslink density due to poor silica dispersion. In addition, the T-3 compound containing high cis BR content showed high crosslink density due to its monosulfide crosslinking structure. Because of the phase separation, SBR/BR blend compounds were easily broken and showed similar $M_{100%}$ and $M_{300%}$ values as those of other compounds despite their high crosslink density. However, the developed blend showed excellent abrasion resistance due to the high cis-1,4 butadiene content and low rolling resistance due to the high crosslink density.

Exposure Characteristics of 1,3-Butadiene Exposed Workers (1,3-부타디엔 제조 및 취급 근로자의 노출특성에 관한 연구)

  • Choi, Ho Chun;An, Sun Hee;Lee, Hyun Seok;Park, Young Wook;Kim, Kyung Soon
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.19 no.4
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    • pp.321-327
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    • 2009
  • 1,3-butadiene is classified as suspected human carcinogen, group A2(American Conference of Governmental Industrial Hygienists, ACGIH). In Korea, 1,3-butadiene has been used as a raw material; monomer, homopolymer, polybutadiene latex, acrylonitrile-butadiene-styrene(ABS) and styrene-butadiene rubber(SBR), in the petrochemistry and precision chemistry industry. As petrochemistry industry in Korea has been developed, the potential exposure possibility of 1,3-butadiene to workers can be increased. Therefore the purpose of this study is to evaluate airborne 1,3-butadiene concentration and workers' exposure levels in the workplace using 1,3-butadiene. Air samples were collected with 4-tert-butyl catechol(TBC) charcoal tube(100 mg/50 mg) and were analyzed by gas chromatograph/flame ionization detector(GC/FID) according to the Choi's method(2002). Geometric mean (GM) and arithmetic mean (AM) of total 59 workers' exposure concentrations to airborne 1.3-butadiene were 0.042 ppm and 1.51 ppm, respectively. Although most samples were lower than 1ppm, 2 samples(21.5ppm and 33.1ppm as 8hr-TWA) were exceeded the Korean standard(2ppm) over 10 times at the repair process in synthetic rubber and resin manufacture industry. 14 samples(41%) of total 34 short-term air samples were exceeded the Korean standard(10ppm as STEL) of Ministry Labor. 1,3-butadiene concentration(GM) in the synthetic rubber and resin manufacture industry(7.87ppm) was significantly higher than that in the monomer manufacure industry (0.35ppm)(p<0.05). Also in the sampling and repair process, each GM(range) was 1.39ppm(N.D.-469.6ppm) and 7.85ppm(N.D.-410.2ppm). In conclusion, it depends on the industry and process, 1,3-butadiene can be exposed to workers as high concentration for short-term.

A Study on the Compatibility of PMMA-Poly(butadiene-g-MMA) Blends (PMMA와 Poly(butadiene-g-MMA) 블렌드의 상용성에 관한 연구)

  • Park, Sung-Ick;Han, Seung;Suh, Kyung-Do;Mun, Tak-Jin
    • Applied Chemistry for Engineering
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    • v.5 no.1
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    • pp.182-188
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    • 1994
  • Poly(butadiene-g-MMA) was synthesized by grafting methyl metharcylate on polybutadiene which is intrinsically incompatible with poly(mothy methacrylate)(PMMA) and this graft copolymer was blended with PMMA. Mechanical properties of PMMA-poly(butadiene-g-MMA) blends and PMMA-polybutadiene blends, such as impact strength, tensile strength and haze were determined. Morphological changes of the blends as a function of graft percentage were observed by scanning electron microscopy. Mechanical properties of PMMA-poly(butadiene-g-MMA) blends were better than PMMA-polybutndiene blends. Especially, mechanical properties of PMMA-poly(butadiene-g-MMA) blends were improved nth increasing graft percentage of MMA.

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Study on the Partial Hydrogenation of Butadiene over Highly Dispersed Supported Gold Catalysts (고분산 담지 금 촉매에 의한 Butadiene의 부분 수소화에 관한 연구)

  • Ahn, Ho-Geun;Hiroo, Niiyama
    • Applied Chemistry for Engineering
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    • v.10 no.7
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    • pp.1003-1007
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    • 1999
  • The activity and products distribution for the hydrogenation of butadiene and pentadiene over the gold and cobalt catalysts prepared by coprecipitation and impregnation method was investigated with using a flow reactor under atmospheric pressure. The reaction characteristics of the highly dispersed gold particles and its role were studied. The activity of the gold catalyst by coprecipitation was much higher than that by impregnation. The selectivity of butene on all gold particles was always 100% even in the absence of butadiene in the stream, but butadiene on cobalt supported catalyst was easily hydrogenated to butane. It was therefore considered that the active sites at circumferences of the gold particles possessed an unique property which took a proper affinity to hydrogen. In the hydrogenation of butadiene and pentadiene, the percentages of 1-butene and 2-pentene were 60%~70% and about 62%, respectively. The results could be simply explained by a statistical concepts of hydrogen addition.

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Alkenylation of o-xylene with 1,3-Butadiene Over Base Catalysts (염기성 촉매를 이용한 o-xylene과 1,3-Butadiene의 알케닐화 반응)

  • Lee, Jong Seok;Lee, Soo Chool;Kil, Min Ho;Choi, Il Seok;Lee, Jae Sung;Kim, Jae Chang
    • Korean Chemical Engineering Research
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    • v.40 no.6
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    • pp.669-675
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    • 2002
  • The alkenylation of o-xylene with 1,3-butadiene to make OTP(ortho-tolyl Pentene) was carried out over liquid phase NaK alloy, Na metal and the metallic sodium dispersed on the specific support such as NaX and $Al_2O_3$. Liquid phase NaK alloy showed the improved conversion and selectivity when they were pretreated by ultrasound to increase the dispersion. For the case of metallic sodium, the induction period for the formation of homogeneous metal sodium solution with high dispersion was needed before the reaction. In the case of metallic sodium dispersed on support, more than 80 % conversion could be obtained without induction period regardless of supports used. But 85 % of the metallic sodium was resolved into the reaction mixture after reaction for 7 hours. The amount of byproducts, oligomers, produced from OTP and 1,3-butadiene increased with the amount of 1,3-butadiene introduced and the selectivity to OTP was in inversely proportional to the conversion.