Linked Life Data

19152956

Source:http://linkedlifedata.com/resource/pubmed/id/19152956

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2009-3-10
pubmed:abstractText
An existing substitution reaction method was improved as part of a system to measure the persistency of selected chemicals in the environment by evaluating their chemical reactivity. Hexachlorobenzene (HCB), pentachlorobenzene, 1,2,4,5-tetrachlorobenzene and 1,2,4-trichlorobenzene were selected as model compounds. Sodium methoxide in methanol was used as a nucleophile and found to be stable for at least 35 days after preparation. The substitution reaction system was modified so that nitrogen protection was not necessary to avoid oxidation and hydrolysis effects, which led to improved results. The reactivity of polychlorinated benzenes (PCBz), which substituted chlorine for methoxide according to a second-order rate constant, increased as the number of chlorine atoms on the benzene ring increased. HCB was selected as a standard for the k(2) calculations of the substitution reactions. A normalized k(2) (k(N)) was calculated as k(N)=k(PCBz)/k(HCB). GC-MS analysis confirmed that the reactions were pure nucleophilic aromatic substitutions without side reactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1879-1298
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
75
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
78-82
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
An improved method for assessing relative nucleophilic substitution reactivities of polychlorinated benzenes.
pubmed:affiliation
Department of Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden. ylqiu@mail.tongji.edu.cn
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't