2Fe +3Cl2<\/sub>\n\u2192 2FeCl3<\/sub><\/p>\n\n\n\n 2Fe + 3Br2<\/sub>\u2192\n2FeBr3<\/sub> <\/p>\n\n\n\n Benzene\nreact with chlorine in the presence of aluminum chloride or iron to prepare\nchlorobenzene.<\/p>\n\n\n\n C6<\/sub>H6<\/sub>\n+ Cl2<\/sub> \u2192 C6<\/sub>H5<\/sub>Cl + HCl<\/p>\n\n\n\n Benzene\nreact with bromine in the presence of aluminum bromide or iron to produce\nbromobenzene. Iron is used because it is readily available and cheaper.<\/p>\n\n\n\n C6<\/sub>H6<\/sub> + Br2 <\/sub>\u2192 C6<\/sub>H5<\/sub>Br + HBr<\/p>\n\n\n\n Addition\nreaction of hot benzene undergo in the presence of ultraviolet light with\nchlorine or bromine. Chlorine or bromine atom adds on carbon atom and ring\ndelocalization is permanently broken [2].<\/p>\n\n\n\n For example: 1,2,3,4,5,6-hexachlorocyclohexane is produced when bubble chlorine gas through hot benzene exposed to UV light for an hour.<\/p>\n\n\n\n Bromine would act similarly, the chlorine and hydrogen make numbers of isomers through sticking up and down at random position of the ring. The carbon-carbon double bond is broken and unable to rotate. Another isomer is commonly used as insecticide called as BCH, HCH, and Gammexane. Also called chlorinated hydrocarbons it is very harmful to the environment..<\/p>\n\n\n\n Substitution Reaction<\/strong><\/p>\n\n\n\n Substitution\nreaction between methylbenzene and chlorine or bromine are take place in two\nways: <\/p>\n\n\n\n Substitution into the ring<\/strong><\/p>\n\n\n\n This\nreaction is carried out at room temperature in the presence of aluminum\nchloride or iron and in the absence of UV light. Methyl group are attached at 2\nor 4 position on the ring and the new group is attach on the ring next to the\nmethyl group. The substitution reaction with chlorine produce two products\n2-chloromethylbenzene and 4- chloromethylbenzene.<\/p>\n\n\n\n C6<\/sub>H5<\/sub>CH3<\/sub> + Cl2<\/sub> \u2192 C6<\/sub>H4<\/sub>CH3<\/sub>Cl + HCl<\/p>\n\n\n\n Substitution into methyl group<\/strong><\/p>\n\n\n\n Substitution\nreaction of chlorine or bromine in the methyl group rather than the ring with\nboiling methylbenzene in the presence of UV light and in the absence of\ncatalyst.<\/p>\n\n\n\n The\nproduct formed is (chloromethyl)benzene, the name written in bracket shows that\nchlorine attached to methyl group and not with the ring.<\/p>\n\n\n\n Hydrogen atoms are replaced in the methyl group by a chlorine atom, all the three hydrogen atoms in the methyl group are replaced by a chlorine atom. The new products are (dichloromethyl)benzene and (trichloromethyl)benzene because hydrogen atom is replaced one at a time.<\/p>\n\n\n\n Formation of the electrophile<\/strong><\/p>\n\n\n\n The delocalization of electron in the ring repel chlorine-chlorine bond, so chlorine molecule approaches the benzene ring [3].<\/p>\n\n\n\n Aluminum\nchloride help in the polarization, positive end of the chlorine molecule act as\nthe electrophile.<\/p>\n\n\n\n First stage <\/strong><\/p>\n\n\n\n Second stage<\/strong><\/p>\n\n\n\n In\nfirst stage hydrogen is removed through AlCl–<\/sup>4<\/sub> ion, but\nin second stage aluminum chloride is regenerated.<\/p>\n\n\n\n First step:<\/strong><\/p>\n\n\n\n Chloronium ion formation, chlorine react with the Lewis acid to form a complex which makes the chlorine more electrophile.<\/p>\n\n\n\n Second step:<\/strong><\/p>\n\n\n\n Chloronium ion attack on the ring. The double bond electrons of the aromatic C=C act as a nucleophile, attacking the electrophilic Cl, and delocalization take place.<\/p>\n\n\n\n Third step:<\/strong><\/p>\n\n\n\n Proton transfer regenerates the aromatic character of the ring.<\/p>\n\n\n\n The\nperson exposed to high level experience headache, numbness, sleepiness, nausea\nand vomiting. Chlorobenzene also effect depression of function of many parts of\nnervous system. In animals mild to severe exposure affect brain, liver and\nkidney. Also cause birth defects.<\/p>\n\n\n\n Explanation Benzene reacts with halogens (salt former) like chlorine and bromine and these reactions are called electrophilic substitution reaction in the presence of catalyst of Lewis acid like aluminum chloride, sulfur dichloride, ferric chloride or iron [1]. Aluminum bromide is used when benzene reacting bromide. Iron is not a catalyst because it reacts with small … Read more<\/a><\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rating_form_position":"","rating_results_position":"","mr_structured_data_type":""},"categories":[55],"tags":[],"multi-rating":{"mr_rating_results":[{"adjusted_star_result":3.33,"star_result":3.33,"total_max_option_value":5,"adjusted_score_result":3.33,"score_result":3.33,"percentage_result":66.67,"adjusted_percentage_result":66.67,"count":3,"post_id":1117}]},"_links":{"self":[{"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/posts\/1117"}],"collection":[{"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/comments?post=1117"}],"version-history":[{"count":3,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/posts\/1117\/revisions"}],"predecessor-version":[{"id":1305,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/posts\/1117\/revisions\/1305"}],"wp:attachment":[{"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/media?parent=1117"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/categories?post=1117"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chemdictionary.org\/wp-json\/wp\/v2\/tags?post=1117"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Reaction with Chlorine<\/h2>\n\n\n\n
Reaction with Bromine<\/h2>\n\n\n\n
![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-2.png\")
<\/figure><\/div>\n\n\n\nAddition Reaction<\/h2>\n\n\n\n
![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-3.png\")
<\/figure><\/div>\n\n\n\n![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-4.png\")
<\/figure><\/div>\n\n\n\nThe halogenation of methylbenzene<\/h2>\n\n\n\n
![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-5.png\")
<\/figure><\/div>\n\n\n\n![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-7.png\")
<\/figure><\/div>\n\n\n\n![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-6.png\")
<\/figure><\/div>\n\n\n\n![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-8.png\")
<\/figure><\/div>\n\n\n\nElectrophilic substitution mechanism<\/h2>\n\n\n\n
![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-9.png\")
<\/figure><\/div>\n\n\n\n![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-56.png\")
<\/figure><\/div>\n\n\n\nMechanism of chlorination of Benzene [4]<\/h2>\n\n\n\n
![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-57.png\")
<\/figure>\n\n\n\n![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-58.png\")
<\/figure><\/div>\n\n\n\n![\"\"](\"https:\/\/chemdictionary.org\/wp-content\/uploads\/2019\/11\/image-59.png\")
<\/figure>\n\n\n\nChlorobenzene uses<\/h3>\n\n\n\n
Health issues <\/h3>\n\n\n\n
References\n<\/h4>\n\n\n\n