It can be subjected to purification in the form of the moist filtration residue, without further drying. In bromination, an element that can donate electrons is being added. The resulting carbocation is unstable compared to the favored electron distribution of the aromatic ring structure; therefore, a hydrogen ion is withdrawn from the ring to neutralize the charge generated by the formation of the nitronium ion. Since this would create a highly unstable transition state, the transition state with the nitronium group in the meta requires less energy to form than the other two states. In the case of the nitronium group, the substituent to be added bears a positive charge; therefore, it seeks electrons. For the purposes of the present invention, an emulsifier is a substance, or a mixture of substances, which permits or facilitates the formation of an emulsion of methyl o-nitrobenzoate in water. The by-products methyl o-nitrobenzoate and p-nitrobenzoic acid which are separated off can be used for further syntheses.
A possible limitation my be the location of a magnet that possesses a plastic coating that is not susceptible to the chemical environment present within the reaction vessel. Because the amine group bears an element that releases electrons to the ring, the electron distribution around the ring shifts. At the end of stage b , the major part of the o-isomer forms an emulsion with the emulsifier and remains in the filtrate after the methyl m-nitrobenzoate has been isolated. Experimental Organic Chemistry A Small Scale Approach. The experiment resulted in 2.
The methyl m-nitrobenzoate is then isolated in a conventional manner, for example by filtering, washing the residue with water, filtering once again and drying. Allow this mixture to cool. Meta-nitromethyl benzoate is the major product for the outlined mechanism due to the substituent attached to the aromatic ring in methyl benzoate. To determine the theoretical yield of methyl m-nitrobenzoate that will be produced, the initial mass of methyl benzoate, measured in grams, must be divided by the molecular weight of methyl benzoate, 136. In general, the resulting methyl m-nitrobenzoate has a purity of 98.
The residue from filtration is washed with water and treated with ice-cold methanol in order to remove the o-ester and other impurities. Despite submersion within an ice bath for more than two minutes, the reaction vessel would continue to increase to temperatures upwards of 30 C. In trying to agitate the mixture, monitor the temperature, and add the acid mixture to the reaction vessel, many mistakes in handling could have been made that result in spilled contents or contaminated reactions. Remove contaminated clothing and shoes. Suitable substances for this purpose are substances as defined in, for example, the chapter on emulsifiers in Ullmanns Enzyklopadie der technischen Chemie Volume 10, pages 455-464, 4th Edition 1975. Conversely, the vessel would also remain at low temperatures despite exposure to room temperature for more than two minutes. A mixture of 1 ml of sulfuric acid and 1 ml 0.
This corresponds to a yield of 93. Skin: Wear appropriate protective gloves to prevent skin exposure. The solvent medium is in general the acid or the acid mixture itself, if necessary mixed with water in the form of an acid mixture of appropriate concentration. If desired, nitric acid and sulfuric acid can be completely or partly replaced with nitrating acid, ie. Department of Homeland Security's Chemical Facility Anti-Terrorism Standards, and the U. The yield is about 80%. Wash the crude product with a little ice-cold water.
Solid methyl 3-nitrobenzoate will form. The mixture is said to contain 72. The precipitation can be carried out under atmospheric or superatomspheric pressure, continuously or batchwise. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed. However, it is not possible to obtain the pure m-nitro ester by the processes described.
The nitration of methyl benzoate with nitric acid for the preparation of the m-nitro compound can be carried out by a conventional method, for example one of the processes described in the above publications. However the 3-position is less deactivated towards nitration than the other positions owing to the relative stability of the different intermediates. Nitration is expediently carried out using nitric acid, advantageously concentrated or fuming nitric acid, in the presence of sulfuric acid, advantageously highly concentrated or fuming sulfuric acid. . The suspension was heated at 75° l C. The o-isomer can be isolated from the filtrate by steam distillation.
Examples 2 To 5 1000 g portions of water-moist methyl 3-nitrobenzoate containing 950 g of crude nitro ester and having the composition: 10. Gently wash all affected skin areas thoroughly with soap and water. Water and an amount, according to the invention, of an emulsifier are then added to the residue, which is not dried beforehand; the total amount of water is brought to the above amount. For the above-mentioned ratio of water to acid, the mixing time is advantageously from 5 to 15 minutes. This is the nitrating mixture. When the nitration mixture is introduced into water, a mixture of the three isomeric methyl nitrobenzoates is obtained; this mixture contains about 10% of the o-isomer and as much as 2% of the p-isomer. Once the initial quantity of methyl benzoate is known, the molar ratio of reactants to products can be used to determine the theoretical yield.
If required, urea is used as the nitration catalyst, advantageously in an amount of from 10 to 100, preferably from 45 to 55, % by weight, based on the methyl ester. This substituent contains a carbon bonded to the aromatic ring that is also attached to two oxygen atoms. The still moist filtration residue advantageously contains from 2 to 35% by weight of water. Depending on the nitration procedure and the method of working-up, this process gives a mixture which contains from 70 to 94% by weight of the m-ester, from 0. In general, from 85 to 100% strength by weight nitric acid and from 98 to 100% strength by weight sulfuric acid are used. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list. A process as claimed in claim 1, wherein the treatment is carried out using a fatty-acid ester, a fatty amine, a fatty-acid amide, a polyglycol ether based on polyethylene oxide or polypropylene oxide, an anionic salt, an organic phosphoric acid compound or a cationic emulsifier.
Ullmanns Encyklop die der Technischen Chemie, vol. The isomer mixture is defined here as a mixture of the 3 isomers without the above-mentioned impurities. In this experiment, the ratio is one to one so no additional calculations are required, and the moles of product is equal to the moles of reactant. A process as claimed in claim 1, wherein the treatment is carried out using a mixture which contains from 70 to 94% by weight of the m-ester, from 0. Department of Transportation hazard labels, and a general description of the chemical. Since the resulting methyl m-nitrobenzoate is virtually pure and contains only traces of impurities, this end product is advantageous for direct further processing, for example catalytic reductive alkylation to give methyl m-N,N-dimethylaminobenzoate.