The Preparation of p-Chlorobenzaldehyde PDF
Preview The Preparation of p-Chlorobenzaldehyde
PURDUE UNIVERSITY THIS IS TO CERTIFY THAT THE THESIS PREPARED UNDER MY SUPERVISION by__________Harry P. McNeil The Preparation of p-Chlorobenzaldehyde entitled COMPLIES WITH THE UNIVERSITY REGULATIONS ON GRADUATION THESES AND IS APPROVED BY ME AS FULFILLING THIS PART OF THE REQUIREMENTS FOR THE DEGREE OF Doctor of Philosophy Professoh in C harge of Thesis Heap of School or Department TO THE LIBRARIAN:-- r*sr THIS THESIS IS NOT TO BE REGARDED AS CONFIDENTIAL. PHOFBSSOB XS CBLAJBQB GPAJD. SCHOOL FORM A THE PREPARATION OF p-CHLOROBENZALDEHYDE A Thesis Submitted to the Faculty of Purdue University by Harry D, McNeil in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy June 1951 ProQuest Number: 27714265 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 27714265 Published by ProQuest LLC (2019). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346 ACKNOWLEDGMENT The author wishes to express his sincere appreciation to Dr. E. T. MeBee, the director of this research, for his able assistance and advice. He is also indebted to Dr. Z. D, Welch for his personal interest and suggestions. The author thanks Commercial Solvents Corporation, Terre Haute, Indiana, and the Purdue Research Foundation for the financial support which made this work possible. He appreciates the technical aid supplied by members of the former organization, particularly Dr. R. S. Egly. TABLE OF CONTENTS Page ABSTRACTS The Chlorométhylation of Chlor©benzene .... i The Preparation of p-Chlorobenzaldehyde by the Sommelet Reaction ........................... xiv INTRODUCTION ........................... 1 PART I THE CHLOROMETHYLATION OF CHLOROBENZENE Introduction ................................. 3 Reaction Conditions ..... 4 Chlorobenzene ............. 5 Paraformaldehyde .... 6 Anhydrous Hydrogen Chloride ...... 9 Zinc Chloride Catalyst ...... 10 Recovered Zinc Chloride ............ 10 Temperature ... 11 Stirring .... 13 Time ..... 13 Isolation of Crude p-ChlorobenzylC hloride ........... 14 Attempted Purification of Crude p-Chlorobenzyl Chlor ide by Distillation ... 1? Attempted Purification of Crude p-Chlorobenzyl Chlor ide by Chromatography......................... 17 Experimental........... 19 Chlorométhylation Apparatus ... 19 Chlorométhylation with Pure ZincC hloride Catalyst ... 20 Chlorométhylation with Recovered Zinc Chloride ....... 21 Page Zinc Chloride Dehydration Apparatus ....... 21 Recovery of the Zinc Chloride Catalyst ....... 22 Isolation of Crude p-Chlorobenzyl Chloride 22 Determination of the Composition of Crude p-Chloro benzyl Chloride............... «.......... 23 Attempted Purification of Crude p-Chlorobenzyl Chloride by Distillation ... 24 Attempted Purification of Crude p-Chlorobenzyl Chloride by Chromatography ..... 24 PART II THE PREPARATION OF p-CHLOROBENZALDEHYDE BY THE SOMME LET REACTION Introduction............... 27 General Considerations........... 29 Methods........ 29 Relative Reactivity of o- and p-Chlorobenzyl Chloride, 31 Experimental ......... 33 1. The Sommelet Reaction in 60% Ethanol Solution 33 2, The Sommelet Reaction through Complex Formation ••• 35 3* The Sommelet Reaction in Water .................... 35 PART III THE HYDROLYSIS OF BENZYL CHLORIDES WITH AQUEOUS UREA Discussion ........................ 37 Experimental .......... *...... 37 Hydrolysis of Benzyl Chloride .............. 37 Hydrolysis of Crude p-Chlorobenzyl Chloride .......... 3# SUMMARY........................... 39 BIBLIOGRAPHY......................... 40 VITA LIST OF TABLES Table Page I. Amount of Chlerebenzene Recovered ...... xi II, Chlorométhylation of Chlorobenzene with Recovered Chlorobenzene Plus Makeup ............... xi III. Chlorométhylation of Chlorobenzene .................... xii IV. Chlorométhylation of Chlorobenzene with Recovered Catalyst ..... xii V. Quantities and Melting Points in the Alkaline Perman ganate Oxidation of Crude p-Chlorobenzyl Chloride ..... xiii VI. Proportions of Materials Used in the Chlorométhylation Reaction .............................. 5 VII. Amount of Chlorobenzene Recovered ............... 6 VIII. Chlorométhylation of Chlorobenzene with Recovered Chlorobenzene Plus Makeup .... 7 IX. Chlorométhylation of Chlorobenzene ....... 9 X. Chlorométhylation of Chlorobenzene with Recovered Catalyst.............. 11 XI. The Oxidation Products of Crude p-Chlorobenzyl Chloride 16 XII. Mixed Melting Point Determination of o- and p~ Chlorobenzoic Acids .... 16 XIII. Distillation of Crude p-Chlorobenzyl Chloride in a Todd Column .... 17 XIV. Refractive Indices of Crude p-Chlorobenzyl Chloride after Passing through Silica Gel in Chloroform ........ 18 (Contribution from the Purdue University Department of Chemistry and the Purdue Research Foundation) The Chlorométhylation of Chlorobenzene 1 E. T. McBee and H. D. McNeil Chlorobenzene is best chlorometbylated in the temperature range of 60°C. to 110°C., using paraformaldehyde and anhydrous hydrogen chlor ide, with zinc chloride as catalyst. The catalyst can be recovered by dehydration. It is possible to obtain conversions of over 70% to a pro duct which contains 19 to 24% o-chlorobenzyl chloride and 76 to 81% p-chlor@benzyi chloride. p-Chlorobenzyl chloride is usually prepared from toluene by chlor ination (3), Since the chlorination of toluene produces 55% o-chloro- toluene and 45%p-chlorotoluene (8), an alternate synthesis based on chlorobenzene has been investigated. Stephen, Short, and Gladding (7) reported 50% conversions to p- chlorobenzyl chloride from the sulfuric acid catalyzed chlorométhylation of chlorobenzene. They also reported good results, at 65*0., when zinc chloride is used as a catalyst. No description of the products obtained by these two methods was given. However, these workers reported that pure p-ehlorobenzyl chloride can be obtained when chlorobenzene is treat ed with monochloromethyl ether in the presence of a dehydrating agent. 1, This paper contains material abstracted from the doctoral thesis of H. D. McNeil whose present address is Hercules Powder Company, Wil mington, Delaware. 11 More recently, (2), the chlorométhylation of benzene has been thoroughly studied by Ginsberg, Huèggerberg, et al, and the most favorable reaction conditions have been established. It is possible to point out two differences in the behavior of ben zene and chlorobenzene in chlorométhylation when the results of Ginsberg, Rueggerberg, et al, are compared with those of Stephen, Short, and Gladding, of , oO -Dichloro-p-xylene is the chief by-product of the chlorométhylation of chlorobenzene, while p,p’-dichlorodiphenylmethane is the side product obtained from chlorobenzene. Chlorobenzene does not react as easily as benzene, since benzene is most successfully chloro- methylated at about 50°C., whereas, chlorobenzene has been chloromethyla- ted at 65*0., using zinc chloride catalysis. This present investigation was concerned with establishing optimum conditions for chlorométhylation of chlorobenzene with zinc chloride, and the determination of the composition of the product. The latter question becomes important in the case of chlorobenzene, since isomer formation is possible. Chlorométhylation Apparatus and Procedure The reaction was carried out in a 1-liter, 4-necked flask. Anhydrous hydrogen chloride was delivered to the flask from a cylinder of that gas by means of a glass tube which reached below the surface of the reaction mixture. The mixture was stirred by a three-inch wire stirrer driven by a motor which had a no-load rating of 1,000 r.p.m. A ground glass ball joint or a mercury seal was used to seal the stirring shaft. Heat was supplied to the reaction mixture by an electric heating mantle, which could be easily substituted by a water bath in case cooling was needed.
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