Home Articles What is Gattermann Koch Reaction Mechanism?

What is Gattermann Koch Reaction Mechanism?

JEE Mains Exam >

Exam

Avantika Bhardwaj
Avantika Bhardwaj

Gattermann Koch Reaction

Definition

The formation of reactive species with the help of the acid is the first step in Gattermann Koch's reaction mechanism. The reaction's overall goal is to attach a formyl group (-CHO group) to an aromatic system. The Gattermann - Koch reaction is illustrated below.

Gattermann Koch Reaction

The Gattermann - Koch reaction does not work on phenol or phenol ether substrates. When using zinc chloride as a catalyst in the Gattermann - Koch reaction, traces of copper(I) chloride are frequently required because it acts as a co-catalyst.

Gattermann Formylation

Named After

Ludwig Gattermann

Reaction Type

Substitution Reaction

Identifiers

RSC Ontology ID

RXNO:0000139

Gattermann Koch Reaction Mechanism

Step 1 - The generation of reactive species that can later be used to react on the aromatic ring is the first step in the Gattermann Koch reaction mechanism. Carbon monoxide can accept a proton from hydrochloric acid because it is a Lewis base. This produces a positively charged molecule with various resonance structures. One such resonance structure has a positive charge on the carbon, which explains the hybrid's reactivity. While reacting with the aromatic ring, this species can act as an electrophile. It is more likely, however, to be the target of a nucleophilic attack by the chloride ion in hydrochloric acid.

Step 2 - When a Lewis acid (Aluminium Chloride) is added, a chloride ion is easily removed from the species. The species has now degenerated into the reactive formyl cation.

Gattermann Koch Reaction

Step 3 - At the aromatic ring, an electrophilic aromatic substitution occurs. As a nucleophile, the aromatic ring donates an electron pair to the formyl cation. A proton expulsion quickly resolves the temporary loss of aromaticity.

Gattermann Koch Reaction

As a result of the Gattermann - Koch reaction, the formyl group is attached to the aromatic ring. In the above example, benzaldehyde is formed by treating benzene with carbon monoxide and hydrochloric acid in the presence of Aluminium Chloride.

Limitations of Gattermann Koch Reaction

Due to a lack of suitable substrates, the Gattermann-Koch reaction is limited to alkylbenzenes; therefore, Gattermann devised a modification that allowed for the formylation of phenols, phenolic ethers, and heteroaromatic compounds such as pyrroles and indoles.

Gattermann Koch Reaction

The Gattermann reaction had one major flaw: anhydrous hydrogen cyanide was required (HCN). To avoid handling HCN, R. Adams created it in-situ from zinc cyanide and hydrochloric acid; this method became known as the Adams modification, and it is now more commonly used in organic synthesis.

Things to Remember in Gattermann Koch Reaction

  • In 1897, L Gattermann and J.A. Koch successfully inserted an aldehyde group on toluene using formyl chloride (HCOCl) as an acylating agent under Friedel-Crafts acylation conditions.
  • The addition of a formyl group to electron-rich aromatic rings using CO/HCl/Lewis acid catalysts (AlX3, FeX3, where X = Cl, Br, I) to produce aromatic aldehydes was named Gattermann-Koch formylation.
  • Carbon monoxide and hydrochloric acid are used as reactants in the Gattermann-Koch Reaction to produce an aryl aldehyde.
  • In the presence of trace amounts of cuprous chloride, aluminium trichloride catalyses the reaction.
  • The Gattermann-Koch Reaction does not apply to phenol and phenol ethers because they "could not be effectively formylated at atmospheric pressure in benzene as a solvent.""The failure to react was blamed on the insolubility of the cuprous chloride in the reaction mixture."

The Gattermann-Koch Formylation method is used to produce substituted benzaldehydes. The formyl cation is the key intermediate in this process, and once formed, it interacts similarly to the other acyl cations in Friedel-Crafts processes.

What are the uses of Gattermann Koch Reaction?

The uses of Gattermann Koch Reaction are as follows:

  • The Gattermann Koch Reaction is used to Synthesize aldehydes from Alkylbenzenes.
  • This reaction is also an industrial reaction to manufacturing Benzaldehyde. 

Other Chemistry Related Articles:

Difference Between Solid, Liquid, and Gas

Schottky Defect

Electrochemical Series

What is the Valency of Carbon?

Frequently Asked Questions

What is Gattermann Koch Reaction?

The Gattermann Koch reaction is defined as a mechanism that begins with the formation of the reactive species with the usage of an Acid. The main objective of the reaction is the attachment of a formyl group (-CHO group) to an aromatic system.

What is Gattermann Koch Reaction Example?

Gattermann Koch Reaction Example – For instance, when Benzene or any of its derivatives is treated with Carbon Monoxide (CO) and Hydrogen Chloride (HCl) in the presence of Anhydrous Aluminimum Chloride or Cuprous Chloride, it produces Benzaldehyde or Su

What are the reagents used in the Gattermann Reaction?

Carbon Monoxide, Hydrogen Chloride, and Aluminium Chloride are used as the reagents in the Gattermann Koch Reaction.

Which cases is the Gattermann Reaction not applicable for?

The Gattermann Koch Reaction stands inapplicable in case of Phenols, or Phenol Ethers. The reason is that Phenol can not be formylated at atmospheric pressure in benzene as a solvent as the catalyst used in the reaction, CuCl remains insoluble in the solv

Which catalyst is used in the Gattermann Koch Reaction?

The catalyst used in the Gattermann Reaction is Aluminium Chloride.

What is the difference between Gattermann and Gattermann-Koch reaction?

The Gattermann Koch Reaction is different from the Gattermann Reaction as Gattermann Koch Reaction used HCl + CO, while the Gattermann Reaction uses HCN + HCl. Besides, the Gattermann Koch Reaction is not applicable when it comes to Phenols and Phenol eth

Gattermann Koch Reaction is an example of?

The Gattermann Koch Reaction is an example of Electrophilic Substitution Reaction.

Which electrophile is used in Gattermann Koch Reaction?

The electrophile used in the Gattermann Koch Reaction is Acylium ion.

What is the product of Gattermann-Koch reaction?

The final product of Gattermann Koch Reaction is Benzaldehyde. When Benzene is treated with Carbon Monoxide in the presence of anhydrous aluminium chloride and acidic medium, the production of Benzaldehyde takes place.

Who discovered the Gattermann Koch Reaction?

Ludwig Gattermann was the first to discover the Gattermann Koch Reaction in 1890. He was a German Chemist.

What is used in the Gattermann Koch Reaction?

It is a variation of the Gattermann reaction that uses CO (carbon monoxide) in the place of hydrogen cyanide. The reaction has been named after German Scientists Lugwig Gattermann and Julius Arnold Koch.

Show More

Similar Articles

NIRF Ranking By - Avantika Bhardwaj10th January, 2024, 2 min read Read More
JAC Delhi Counselling 2024 By - Avantika Bhardwaj25th April, 2024, 10 min read Read More
JAC Chandigarh 2024 Counselling By - Avantika Bhardwaj25th April, 2024, 9 min read Read More
View All
Check Eligibility Apply Now
Request history8.3.17PHP Version128msRequest Duration3MBMemory UsageGET articles/{slug}Route
    • Booting (9.72ms)time
    • Application (118ms)time
    • 1 x Application (92.41%)
      118ms
      1 x Booting (7.59%)
      9.72ms
      11 templates were rendered
      • pages.article.descriptiondescription.blade.php#?blade
      • components.breadcrumbbreadcrumb.blade.php#?blade
      • components.author-detailsauthor-details.blade.php#?blade
      • components.faqfaq.blade.php#?blade
      • components.registrationregistration.blade.php#?blade
      • layouts.webweb.blade.php#?blade
      • partials.headhead.blade.php#?blade
      • partials.headerheader.blade.php#?blade
      • partials.footerfooter.blade.php#?blade
      • components.sucessesModalsucessesModal.blade.php#?blade
      • partials.bottomfooterbottomfooter.blade.php#?blade
      uri
      GET articles/{slug}
      middleware
      web
      domain
      www.dev.collegesearch.in
      controller
      App\Http\Controllers\ArticleController@description
      as
      article.description
      namespace
      prefix
      /articles
      where
      file
      app/Http/Controllers/ArticleController.php:77-122
      11 statements were executed (2 duplicates)Show only duplicates62.82ms
      • SoftRedirects.php#22db_collegesearch_newConnection Established
        Backtrace
        • app/Http/Middleware/SoftRedirects.php:22
        • vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php:183
        • vendor/laravel/framework/src/Illuminate/Routing/Middleware/SubstituteBindings.php:51
        • vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php:183
        • vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/VerifyCsrfToken.php:88
      • SoftRedirects.php#22db_collegesearch_new10.56msselect * from `seo_redirects` where `redirect_from` = '/articles/gattermann-koch-reaction-exm' limit 1
        Bindings
        • 0: /articles/gattermann-koch-reaction-exm
        Backtrace
        • app/Http/Middleware/SoftRedirects.php:22
        • vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php:183
        • vendor/laravel/framework/src/Illuminate/Routing/Middleware/SubstituteBindings.php:51
        • vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php:183
        • vendor/laravel/framework/src/Illuminate/Foundation/Http/Middleware/VerifyCsrfToken.php:88
      • MetaChecker.php#20db_collegesearch_new980μsselect * from `meta_tags` where `slug` = 'articles/gattermann-koch-reaction-exm' and `meta_tags`.`deleted_at` is null and `status` = 'active' limit 1
        Bindings
        • 0: articles/gattermann-koch-reaction-exm
        • 1: active
        Backtrace
        • app/Http/Middleware/MetaChecker.php:20
        • vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php:183
        • app/Http/Middleware/SoftRedirects.php:28
        • vendor/laravel/framework/src/Illuminate/Pipeline/Pipeline.php:183
        • vendor/laravel/framework/src/Illuminate/Routing/Middleware/SubstituteBindings.php:51
      • ArticleController.php#82db_collegesearch_new2.44msselect * from `articles` where (`slug` = 'gattermann-koch-reaction-exm' and `type` = 'article') and `articles`.`deleted_at` is null and `articles`.`status` = 'active' limit 1
        Bindings
        • 0: gattermann-koch-reaction-exm
        • 1: article
        • 2: active
        Backtrace
        • app/Http/Controllers/ArticleController.php:82
        • vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php:47
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:266
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:212
        • vendor/laravel/framework/src/Illuminate/Routing/Router.php:808
      • ArticleController.php#82db_collegesearch_new1.66msselect `id`, `name`, `email`, `image` from `admins` where `admins`.`id` in (151) and `admins`.`deleted_at` is null
        Bindings
        • 0: 151
        Backtrace
        • app/Http/Controllers/ArticleController.php:82
        • vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php:47
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:266
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:212
        • vendor/laravel/framework/src/Illuminate/Routing/Router.php:808
      • ArticleController.php#92db_collegesearch_new5.09msselect * from `exams` where `id` = 161 and `exams`.`deleted_at` is null and `status` = 'active' limit 1
        Bindings
        • 0: 161
        • 1: active
        Backtrace
        • app/Http/Controllers/ArticleController.php:92
        • vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php:47
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:266
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:212
        • vendor/laravel/framework/src/Illuminate/Routing/Router.php:808
      • ArticleController.php#92db_collegesearch_new1.52msselect * from `courses` where `courses`.`id` in (1) and `courses`.`deleted_at` is null and `status` = 'active'
        Bindings
        • 0: active
        Backtrace
        • app/Http/Controllers/ArticleController.php:92
        • vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php:47
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:266
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:212
        • vendor/laravel/framework/src/Illuminate/Routing/Router.php:808
      • Exam.php#57db_collegesearch_new1.61msselect `exam_feature_mappings`.`value`, `exam_feature_mappings`.`exam_feature_id` from `exam_feature_mappings` inner join `exam_features` on `exam_features`.`id` = `exam_feature_mappings`.`exam_feature_id` where `exam_feature_mappings`.`exam_id` = 161 and `exam_features`.`type` = 'exam_date' and `exam_feature_mappings`.`deleted_at` is null and `exam_feature_mappings`.`status` = 'active' limit 1
        Bindings
        • 0: 161
        • 1: exam_date
        • 2: active
        Backtrace
        • app/Models/Exam.php:57
        • app/Http/Controllers/ArticleController.php:92
        • vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php:47
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:266
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:212
      • Article.php#109db_collegesearch_new7.86msselect * from `articles` where `type` = 'article' and (`link_id` = 161 and `link_type` = 'exam') and `articles`.`deleted_at` is null and `articles`.`status` = 'active' limit 3
        Bindings
        • 0: article
        • 1: 161
        • 2: exam
        • 3: active
        Backtrace
        • app/Models/Article.php:109
        • app/Http/Controllers/ArticleController.php:110
        • vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php:47
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:266
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:212
      • Article.php#109db_collegesearch_new1.99msselect `id`, `name`, `email`, `image` from `admins` where `admins`.`id` in (151) and `admins`.`deleted_at` is null
        Bindings
        • 0: 151
        Backtrace
        • app/Models/Article.php:109
        • app/Http/Controllers/ArticleController.php:110
        • vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php:47
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:266
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:212
      • Article.php#27db_collegesearch_new27.51msselect `question`, `answer` from `faqs` where `faqs`.`faq_type` = 'article' and `faqs`.`faq_id` = 231 and `faqs`.`faq_id` is not null and `faqs`.`deleted_at` is null
        Bindings
        • 0: article
        • 1: 231
        Backtrace
        • app/Models/Article.php:27
        • app/Http/Controllers/ArticleController.php:116
        • vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php:47
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:266
        • vendor/laravel/framework/src/Illuminate/Routing/Route.php:212
      • helpers.php#157db_collegesearch_new1.6msselect * from `brandings` where `section` = 'article' and `brandings`.`deleted_at` is null and `status` = 'active'
        Bindings
        • 0: article
        • 1: active
        Backtrace
        • app/helpers.php:157
        • vendor/laravel/framework/src/Illuminate/Filesystem/Filesystem.php:124
        • vendor/laravel/framework/src/Illuminate/View/Engines/PhpEngine.php:58
        • vendor/laravel/framework/src/Illuminate/View/Engines/CompilerEngine.php:75
        • vendor/laravel/framework/src/Illuminate/View/View.php:209
      App\Models\Faq
      11Faq.php#?
      App\Models\Article
      4Article.php#?
      App\Models\Admin
      2Admin.php#?
      App\Models\Branding
      2Branding.php#?
      App\Models\Exam
      1Exam.php#?
      App\Models\Course
      1Course.php#?
          _token
          cc5iD08HfBDEmDFjzKsSCNzuryQovWENUyPw0Rbv
          _previous
          array:1 [ "url" => "https://www.dev.collegesearch.in/articles/gattermann-koch-reaction-exm" ]
          _flash
          array:2 [ "old" => [] "new" => [] ]
          path_info
          /articles/gattermann-koch-reaction-exm
          status_code
          200
          
          status_text
          OK
          format
          html
          content_type
          text/html; charset=UTF-8
          request_query
          []
          
          request_request
          []
          
          request_headers
          0 of 0
          array:15 [ "host" => array:1 [ 0 => "www.dev.collegesearch.in" ] "priority" => array:1 [ 0 => "u=0, i" ] "accept-encoding" => array:1 [ 0 => "gzip, deflate, br, zstd" ] "sec-fetch-dest" => array:1 [ 0 => "document" ] "sec-fetch-user" => array:1 [ 0 => "?1" ] "sec-fetch-mode" => array:1 [ 0 => "navigate" ] "sec-fetch-site" => array:1 [ 0 => "none" ] "accept" => array:1 [ 0 => "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7" ] "user-agent" => array:1 [ 0 => "Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)" ] "upgrade-insecure-requests" => array:1 [ 0 => "1" ] "sec-ch-ua-platform" => array:1 [ 0 => ""Windows"" ] "sec-ch-ua-mobile" => array:1 [ 0 => "?0" ] "sec-ch-ua" => array:1 [ 0 => ""HeadlessChrome";v="129", "Not=A?Brand";v="8", "Chromium";v="129"" ] "cache-control" => array:1 [ 0 => "no-cache" ] "pragma" => array:1 [ 0 => "no-cache" ] ]
          request_cookies
          []
          
          response_headers
          0 of 0
          array:5 [ "content-type" => array:1 [ 0 => "text/html; charset=UTF-8" ] "cache-control" => array:1 [ 0 => "no-cache, private" ] "date" => array:1 [ 0 => "Sun, 23 Feb 2025 12:59:06 GMT" ] "set-cookie" => array:4 [ 0 => "XSRF-TOKEN=eyJpdiI6IkhLd2pLY05jMk9tODNqMmFXdElNY3c9PSIsInZhbHVlIjoiemhGZ1Qwc2x4YlVzeVlqRkV6RGIwVkJPR0hnNDVnNDM4NGFwZDVYeUlwVnV1NFNMZHEvaFJwb1E2ZnRNeElvU0pHK09iMENWVyt4MmEzNmhOK281MzJYMExxYjdCOU42cmZoSVVXdHhGNlJDeWUxUzg5SGxuY0RKbnBzeUVnUW8iLCJtYWMiOiJhN2QyNTE5Mzk3NWQ1OTEwMzg3YTQwNGNkNWIzYjlkNzYyNDQ3ODRhYzY2Y2IyMmU5ODAxMGY2ZGY5ZWI0YWFkIiwidGFnIjoiIn0%3D; expires=Sun, 23 Feb 2025 14:59:06 GMT; Max-Age=7199; path=/; secure; samesite=laxXSRF-TOKEN=eyJpdiI6IkhLd2pLY05jMk9tODNqMmFXdElNY3c9PSIsInZhbHVlIjoiemhGZ1Qwc2x4YlVzeVlqRkV6RGIwVkJPR0hnNDVnNDM4NGFwZDVYeUlwVnV1NFNMZHEvaFJwb1E2ZnRNeElvU0pHK09iM" 1 => "laravel_session=eyJpdiI6IlQzSXpNMWIzZGhINkRtVEQ5SE5Tc1E9PSIsInZhbHVlIjoiMFgwVXg2WnZ4Y2MvK0pJa2lraUZuUjB3TjV5TDhkb0JnV1NQejl6VGlnNGgxbWc2ZmRtcUpBVmVlTy9Od3U3VEw3anloS1FmSVltdGxZSEw3LzRBQ2g5ODY5MVR4SnhkL2IrY21ranRncUdTWS9MWXppR1ZlTXdJUXA1eVV0UXoiLCJtYWMiOiI4MjAzZWZmMThhZGY5ODcwMzk3YzZjNGVjNDdmMWY2OGIzZTg2ZGM2ZjZhOWI3NTcwMjNjNmVhM2E1ZWYwNTk5IiwidGFnIjoiIn0%3D; expires=Sun, 23 Feb 2025 14:59:06 GMT; Max-Age=7199; path=/; secure; httponly; samesite=laxlaravel_session=eyJpdiI6IlQzSXpNMWIzZGhINkRtVEQ5SE5Tc1E9PSIsInZhbHVlIjoiMFgwVXg2WnZ4Y2MvK0pJa2lraUZuUjB3TjV5TDhkb0JnV1NQejl6VGlnNGgxbWc2ZmRtcUpBVmVlTy9Od3U3VEw3" 2 => "course_id=1; expires=Mon, 23 Feb 2026 12:59:06 GMT; Max-Age=31535999; path=/; samesite=lax" 3 => "course_name=B.Tech%20%2F%20B.E.; expires=Mon, 23 Feb 2026 12:59:06 GMT; Max-Age=31535999; path=/; samesite=lax" ] "Set-Cookie" => array:4 [ 0 => "XSRF-TOKEN=eyJpdiI6IkhLd2pLY05jMk9tODNqMmFXdElNY3c9PSIsInZhbHVlIjoiemhGZ1Qwc2x4YlVzeVlqRkV6RGIwVkJPR0hnNDVnNDM4NGFwZDVYeUlwVnV1NFNMZHEvaFJwb1E2ZnRNeElvU0pHK09iMENWVyt4MmEzNmhOK281MzJYMExxYjdCOU42cmZoSVVXdHhGNlJDeWUxUzg5SGxuY0RKbnBzeUVnUW8iLCJtYWMiOiJhN2QyNTE5Mzk3NWQ1OTEwMzg3YTQwNGNkNWIzYjlkNzYyNDQ3ODRhYzY2Y2IyMmU5ODAxMGY2ZGY5ZWI0YWFkIiwidGFnIjoiIn0%3D; expires=Sun, 23-Feb-2025 14:59:06 GMT; path=/; secureXSRF-TOKEN=eyJpdiI6IkhLd2pLY05jMk9tODNqMmFXdElNY3c9PSIsInZhbHVlIjoiemhGZ1Qwc2x4YlVzeVlqRkV6RGIwVkJPR0hnNDVnNDM4NGFwZDVYeUlwVnV1NFNMZHEvaFJwb1E2ZnRNeElvU0pHK09iM" 1 => "laravel_session=eyJpdiI6IlQzSXpNMWIzZGhINkRtVEQ5SE5Tc1E9PSIsInZhbHVlIjoiMFgwVXg2WnZ4Y2MvK0pJa2lraUZuUjB3TjV5TDhkb0JnV1NQejl6VGlnNGgxbWc2ZmRtcUpBVmVlTy9Od3U3VEw3anloS1FmSVltdGxZSEw3LzRBQ2g5ODY5MVR4SnhkL2IrY21ranRncUdTWS9MWXppR1ZlTXdJUXA1eVV0UXoiLCJtYWMiOiI4MjAzZWZmMThhZGY5ODcwMzk3YzZjNGVjNDdmMWY2OGIzZTg2ZGM2ZjZhOWI3NTcwMjNjNmVhM2E1ZWYwNTk5IiwidGFnIjoiIn0%3D; expires=Sun, 23-Feb-2025 14:59:06 GMT; path=/; secure; httponlylaravel_session=eyJpdiI6IlQzSXpNMWIzZGhINkRtVEQ5SE5Tc1E9PSIsInZhbHVlIjoiMFgwVXg2WnZ4Y2MvK0pJa2lraUZuUjB3TjV5TDhkb0JnV1NQejl6VGlnNGgxbWc2ZmRtcUpBVmVlTy9Od3U3VEw3" 2 => "course_id=1; expires=Mon, 23-Feb-2026 12:59:06 GMT; path=/" 3 => "course_name=B.Tech+%2F+B.E.; expires=Mon, 23-Feb-2026 12:59:06 GMT; path=/" ] ]
          session_attributes
          0 of 0
          array:3 [ "_token" => "cc5iD08HfBDEmDFjzKsSCNzuryQovWENUyPw0Rbv" "_previous" => array:1 [ "url" => "https://www.dev.collegesearch.in/articles/gattermann-koch-reaction-exm" ] "_flash" => array:2 [ "old" => [] "new" => [] ] ]
          ClearShow all
          Date ↕MethodURLData
          #12025-02-23 12:59:07GET/articles/gattermann-koch-reaction-exm111121