Manufacture and use of chloroprene monomer

Lynch, Michael

doi:10.1016/s0009-2797(01)00188-0

Cited by 36 publications

(48 citation statements)

References 1 publication

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“…Chloroprene production in 1989 reached 373 000 tonnes [1]. The reaction processes involved in chloroprene and DCBD synthesis take place in "closed" systems, which are designed to avoid exposure to humans and the environment, but some leaks and accidental spills inevitably occur [2]. These compounds frequently occur in waste streams and have the potential to be released to the subsurface.…”

Section: Introductionmentioning

confidence: 99%

Degradation of chlorinated butenes and butadienes by granular iron

Hughes¹,

Gillham²,

Gui³

2008

WIT Transactions on Ecology and the Environment

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Sites where chlorobutyl rubber is produced have the potential to release a mixture of chlorinated butenes and butadienes, which are known to be toxic and persistent, into the groundwater environment. The potential contaminants include trans-1,4-dichlorobutene-2 (1,4-DCB-2), 3,4-dichlorobutene-1 (3,4-DCB-1), 2,3,4-trichlorobutene-1 (2,3,4-TCB-1), 2-chlorobutadiene-1,3 (chloroprene) and 2,3-dichlorobutadiene-1,3 (DCBD). Granular iron has been shown to reductively dechlorinate a number of compounds and has been used in permeable reactive barriers (PRBs) for in-situ groundwater remediation. To evaluate the possibility of using granular iron for the remediation of the above contaminants, a series of batch experiments were conducted. Results show that dechlorination reactions for chlorinated butenes closely followed pseudo-first-order kinetics with normalized half-lives ranging from 5.1 to 7.5 h. Chlorinated butadienes degraded much slower in batch tests with normalized half-lives ranging from 38.8 to 128 h. Chlorine mass balance calculations showed that 1,4-DCB-2, 3,4-DCB-1 and chloroprene were fully dechlorinated by granular iron. 2,3,4-TCB-1 was transformed to chloroprene as an intermediate via a reductive β-elimination pathway. Neither the presence of CaCO 3 nor temperature affected degradation rates suggesting that mass transport to iron surfaces was limiting degradation in batch tests. A column experiment was conducted on 3,4-DCB-1 and a normalized half-life of 1.6 min was found. Faster degradation in the column was thought to be due to enhanced mixing effects. 3,4-DCB-1 was converted to 1,3-butadiene via reductive β-elimination, which was then converted to a mixture of 1-butene, cis-2-butene and trans-2-butene via catalytic hydrogenation.

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Section: Introductionmentioning

confidence: 99%

Degradation of chlorinated butenes and butadienes by granular iron

Hughes¹,

Gillham²,

Gui³

2008

WIT Transactions on Ecology and the Environment

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“…34 Consequently, the release of chloroprene during the manufacturing process and transportation has been strictly regulated, and chloroprene has been manufactured mostly in sealed systems. 35 Its presence in the air has been demonstrated at manufacturing plants, but the occurrence and concentration detected are generally low. 36 While we analyzed exhaled breath samples stored in ALTEF bags, we unexpectedly detected the four dimerization products of chloroprene that turned out to be the background contaminants emitted from the bag material.…”

Section: Discussionmentioning

confidence: 99%

Dimerization Products of Chloroprene are Background Contaminants Emitted from ALTEF (Polyvinylidene Difhioride) Gas Sampling Bags

et al. 2017

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Gas sampling bags have been used for collecting air samples. Tedlar bags are most commonly used, but bleed background chemicals such as N,N-dimethylacetamide and phenol. It is often necessary to remove the contaminant by flushing the bags with pure nitrogen or air. In this study, we identified four chloroprene dimerization products as background contaminants emitted from ALTEF bags that are made of a proprietary polyvinylidene difluoride (PVDF). No monomer chloroprene was detected in the bags analyzed. All of the dimers gradually increased once bags were filled with nitrogen due to diffusion from the bag surface. Flushing the bags with nitrogen reduced their concentrations, but was not effective for removing the contaminants. When the bags that had been flushed with nitrogen 5 times were left for 24 h, they increased again, indicating that the dimers were constantly emitted from the ALTEF bag surface. To our knowledge, these compounds have never been demonstrated in ALTEF or other PVDF bags. Our finding indicates that ALTEF might be incorporated with Neoprene (chloroprene-based polymer) during its manufacturing process.

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“…3 The properties of neoprene are created during vulcanization, the process of cross-linking polymer chains, which requires the addition of various compounds. 3 The properties of neoprene are created during vulcanization, the process of cross-linking polymer chains, which requires the addition of various compounds.…”

Section: N Eoprene Was First Discovered In 1930 and Ismentioning

confidence: 99%