US1875916A - Process of making organic intermediates - Google Patents

Description

A No Drawing.

riser WORKS, INC., OF .YQBK, N. Y., A CORPORATION OF VIRGINIA i rnoonss-ornnxme oRGAivIo INTERMEDIATES} This invention relatesto the production of organic intermediates and particularly to processes of substituting the halogen 1n halogen-nitrobenzenes with an alkoxy group to form alkoxy nitrobenzenes, and has as a general object the production of such compounds in a convenient, efiicient andeconomical manner. 7

A more specific object of the invention to provide a process of preparing alkoxynitrobenzene' from halogemnitrobenzenes 1n approximately quantitative yields, at. nor; mal pressure and at relatively low temperatures.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others thereof, which will be exemplified in the process hereinafter dlsclosed, and the scope of the application of which will be indicated in the claims.

alkoxy-nitrobenzenes have therefore either.

Experimental attempts have'been made to prepare these compounds by heating the halogen-nitrobenzenes with metallic alcoholates but, due to the steps employed, various side reactions occurred resulting in the for-.

mation of aZo and azoxy compounds and the yields of alkoxy-nitrobenzenes was consequently small.

Commercial methods of preparing the utilized materials of an entirely different type or have resorted to the use of caustic alkalies and water to decrease the violence and rapidity of the reaction, in an endeavor h to minimize the loss due to the side reactions. Heating under pressure was fre quently used in such processes, the materials were generally all present at the beginning and the yields were unsatisfactory for economical commercial operation.

I have discovered that the aforesaid side reactions may be substantially entirely avoided, and approximately theoretical yields of alkoxy-nitrobenzenes may be obtained from the halogen-nitrobenzene used, if the metallicalcoholate, prepared by dissolving an alkali Application filed. August 13,1926, se i rn'o.129,089)

metal in dry alcohol, is slowly addedtothe heated halogen-nitrobenzene. By such procedure I have found that although thetemper ature and pressure may be varied within quite wide limits, neverthelessit is both convenient and practical to carry out the reaction at rela tively low temperatures, as, for example, at

about the boiling pointof the alcohol used.

As alresult of the possibility of using such temperatures, it is not necessary that the halo gen-nitrobenzene be diluted with'alcohol, as heretofore, although, due to the tendency to thicken during the reaction, such dilution is generally desirable. Also I have found that other substances may be used as a diluent;="although the use of alcohol is preferred since it can then subsequently be distilled off from the mass and used directly again Without pus rification.

The following example is illustrativegof tised:

In the preparation of ortho-nitroanisole, 157.5 parts by weight-0f ortho-nitrochloro benzene is mixed with an equal weight" of methyl alcohol and heatedtoabo'ut- C. under a reflux. A solution of' 23 parts by" Weight of metallic sodium dissolved in about the manner in which my process may be'prac- ERIK CLEMMENSEN, or NEWARK, NEW YORK, AssIeNon 'ro rm'rninson Ankara 200 parts of methyl alcohol is added slowly at a rate such that there is at no time present a substantial excess of the alcoholate. The

temperatureis maintained at about 70 0.,

the time of addition being about/l8 hours. Thereafter the methyl alcohol is distilledoff and enough water is added to the remainder to dissolve the formeds'odium chloride. At this time the ortho-nitroanisole separates as a layer 'on top of the sodium chloridesolution and may be separated in the usual way. The l yield is substantially quantitative. .7

Although the above example is illustrative only of the process of preparingortho-nitroa-nisole, yet it is to be understood that my invention is applicable to the preparationof other compounds of a similar nature, such as, para-nitroanisole, di-nitroanisole etc and that other halogen-nitrobenzenes such as para-nitrochloro benz'enes, di-nitrochlorobenzene etc., and other alcoholateslsuch as ethyl alcoholate etc, and other alkali metals may be used if desired; also as pointed out above,

other temperatures may be used; a particular any given instant.

Since certain changes may be made in carrying out the above process without departing from the scope of the invention, it is intended that all matter contained in the above" description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic andspecific features of they invention herein described, and all statements of the scopeofthe invention which, as a. matter of language, might. be said to fall the-rebetween.

.Having described my invention, what I claim asnew and desireto secure by Letters Patent is: I a 1 v 1. A process of making an alkoxy-nitrobenzene which includes slowly adding a metallic alcoholate'to a halogen-nitrobenzene while maintaining the mixture at substantially atmospheric pressure and at an elevated temperature.

2. Aprocess of making an alkoxy-nitrobenzene which includes slowly adding a me tallic alcoholate to a halogen-nitrobenzene in the presence of a solvent of the latter com pound while maintaining the mixture at substantially atmospheric pressure and at an elevated temperature.

3. A process of making an alkoxy-nitrobenzene which comprises slowly adding an alcoholic solution of a metallic alcoholate to a halogen-nitrobenzene while holding the mixtureat a temperatureof approximately the boiling point of the alcohol and at sub stantially atmospheric pressure.

4:. A process of making an alkoxy-nitrobenzene which comprises slowly adding an alcoholic solution of a metallic alcoholate to a halogen-nitrobenzene at a rate such that there is at no time present a substantial uncombined quantity of unreacted alcoholate, while holding the mixture at a temperature of approximately the boiling point of the alcohol and at substantially atmospheric pressure. r

5. Aprocess of making a nitroanisole which includes slowly. adding a solution formed by dissolving analkali metal in methyl alcohol to a halogen nitrobenzene while maintaining the mixture at substantially atmospheric pressure and at an elevated temperature.

6. A process of making a nitroaniso le which includes slowly adding a solution formed by dissolving an alkali metal in methyl alcohol, to a halogen-nitrobenzene,

' while holding the mixture at about C.

7. A process of making a nitroanisole which comprises slowly adding a solution cohol.

about 70 C.' under a reflux, and, while maintaining the temperature substantially constant, slowly adding a solution formed by 'dissolving'an alkali metal in methyl al- 9. A process which, comprises diluting 157 .5 parts by weight of ortho-nitrocholorobenzene with approximately an equal amount of methyl alcohol, heating-the mixture to about 70 C.

under a reflux, and, while maintaining the temperature substantially constant, adding to; the mixture a solution formed by dissolving 23 parts by weight of metallic sodium in about200 parts of methyl alcohol, theaddi tion being made at a rate such that *there is of making ortho-nitroanisole at no timepresent a substantial quantity of I unreacted alcoholate. e g

In testimonywhereof I aflix my signature.

7 ERIK CLEMMENSEN.