2,829,029 United Stat“ Patent 1C6" iiaténted' Apr. '1, ‘1,958 1 2 action can be carried out by, passing gaseous boron tri fluoride into liquid dinitrogen trioxide but we prefer to 2,829,029 employ, theinert solvent such as a nitropara?in men COMPLEX OF BORON TRIFLUORIDE AND NITRO- . -GEN‘TRIOXIDEAND PROCESS FOR PRODUC tioned above. The completion of the reaction is indi . lNG SAME " ‘ V > I cated by the disappearance of the blue color of dinitro gen trioxide and the evolution of unreacted white bo ‘ Gustave B. Bachman, Lafayette, Ind., and Takeo Hoitama, ron tri?uoride fumes. - When the reactants are contacted, Hilo, Territory of Hawaii, assignors to Purdue Research the insoluble complex is produced and is precipitated Foundation, Lafayette, 11111., a vcorporation - from the reaction mixture' The complex is stable in No Drawing. Application October 3, 1956 the nitropara?‘ins as indicated above and may be stored . Serial No. 613,611 - e for some time in this manner. However, the solid com plex may be isolated by vacuum ?ltration although a dry 5 Claims. (Cl. 23-14) atmosphere is required to prevent decomposition of the complex by the moisture in the air. ‘Dry, liquid dinitro Our invention relates to a newv composition of boron 15 gen trioxide can be obtained by saturating dry liquid tri?uoride and dinitrogen trioxide and moreparticularly, dinitrogen tetroxide with nitric oxide at ,—70° C. The it relates to a'complex‘ between boron‘ tri?uoride and v dry liquid dinitrogen tetroxide can be obtained by the dinitrogen trioxide in a molar ratio of one to one and method of Henderson and Fernelius, Organic Prepara to the method of producing the same. tions, McGraw-Hill Book Co., Inc. (1935), page 44. Kuhlmann, in ‘1841, reported in Ann. ‘39,320, that 20 We prefer to place dry nitromethane or nitroethane boron tri?uoride reacted "with nitric oxide but he did - in aasuitable container and add dry liquid dinitrogen not identify the product nor give any analytical data ‘ tetroxide to the cooled solvent after which the nitric ox from which the composition of the product could be cal ide gas is slowly bubbled into the solution while the tern-r culated. Batey and Sisler reported in the Journal, of perature is lowered to ——70° C. The low temperature the American Chemical Society, vol. 74, page 3408, that ‘is employed to minimize the dissociation of dinitrogen when nitryl'chloride was contacted with boron tri?uo-_ trioxide. When brown fumes begin to be emitted from ride, no reaction took place except thatboron tri?uoride the solution as. a result of unabsorbed nitric oxide be did react with dinitrogen tetroxide impurity in the nitryl , ing oxidized to nitrogen dioxide, by the air, the nitric chloride to produce N2O312BF8, a white crystalline solid. oxide ?ow is stopped and we vthen pass the gaseous bo Finlay reported in the‘Journal of Chemical’ Education, 3.0 ron tri?uoride into the reaction vessel to product the vol. 24, page 149, that the compoundBFS-NO could be boron ‘tri?uoride-dinitrogen trioxide complex as indicated made by cooling a mixture of NO and BF; in a sealed above. IThe yield of the complex is'essentially quanti tube. Bachman, Feuer, 'Bluestein and Vogt reported tative. ' j in Journal-of the American Chemical Cociety, volume The following example is offered to illustrate the pro 77, page 6188, the preparationof thecomplex Bids-N204. duction' of our new complexvbut we do not‘ intend to be We havenow discovered a new; composition which‘ is limited to vthe particular materials, proportions, or pro a complex between boron tri?uoride and dinitrogen tri cedures shown. Rather we intend to include within the oxide, BF3-N2O3.' Our new composition and the method scope of our invention all equivalents obvious to those of producing it have not previously been described. The skilled in the art. complex Elia-N203 is a stable, white, powdery solid 40 Example I which is hygroscopic and is decomposed upon exposure to moisture. The new complex is essentially insoluble A SOO-ml. portion'of dry nitroethane was placed in a in all solvents with which it does not react. Decompo three-neck 500 ml. ?ask ?tted with a stirrer, a re?ux sition of the complex occurs with such solvents as eth condenser with a drying tube and a gas inlet tube which anol, ethyl ether, acetone, acetic acid, and pyridine. Sol 45 extended just below the surface of ‘the nitroethane. The vents which do not decompose the complex readily at ?ask was cooled to. —-20° C. after which 23 grams of room temperature and below include nitroparai?ns, pe dry liquid dinitrogen tetroxide was added and then dry troleum ether, cyclohexane, carbon tetrachloride, chlo I nitric oxide slowly bubbled into the solution, the tem roform, and nitrobenzene. Attempts to determine a melt perature being lowered to —-70° C. during the introduc ing point in sealed tubes resulted in no liquid phase up 50 tion of ‘the nitric oxide. Complete saturation of the di to 290° C., although considerable dissociation occurred nitrogen ~tetroxide was indicated by the oxidation of ni as evidenced by the formation of red-brown fumes. The ' ‘tric oxide to brown nitrogen dioxide at the mouth of the combining weights of boron tri?uoride and, dinitrogen condenser; Gaseous boron tri?uoride was then bubbled trioxide ' were determined carefully employing gravi into the reaction vessel until dense white fumes were metric methods and the structure BF3-N2O3 thereby 55 observed emitting from the top of the condenser and the corroborated. blue color of ‘dinitrogen trioxide disappeared. The white As indicated above, our new compositionis insoluble solid complex of dinitrogen trioxide and boron tri?u~ in most solvents with which it does not react. Water oride precipitated from the solution as it was being and most organic solvents containing oxygen atoms re formed. The yield was quantitative. act rapidly to destroy the complex with the evolution of 60 Our new complex of boron tri?uoride and dinitrogen gaseous by-products or reaction products with the sol trioxide is a useful diazotizing agent and is useful in vents. The complex is essentially insoluble in solvents diazotizing primary aromatic amines, particularly weakly with which it does not react such as those mentioned basic aromatic amines in non-aqueous solvents, and in above so that the complex can safely be stored in these preparing pure, dry, stabilized diazonium salts. The re 65 materials at room temperature or below. action is not limited to the diazotization of weakly basic‘ Our new complex of boron tri?uoride and dinitrogen aromatic amines, however, the diazotization of such com- trioxide can be prepared by reacting boron tri?uoride pounds is extremely troublesome using ordinary diazo‘ with dinitrogen trioxide. ‘The reaction is exothermic tization procedures because of the weak basicity of the and must be carried out under carefully controlled tem compound. In carrying out the diazotization reaction, the perature conditions. The reaction can be carried out material to be diazotized is contacted with the complex by passing gaseous boron tri?uoride into a solution of of boron tri?uoride and dinitrogen trioxide and the re- dinitrogen trioxide in a nitroparaf?n solvent. - The re sulting precipitated diazonium salt subsequently isolated. 2,829,029 4 Preferably we‘ employ a“ 0.1 molar excess of the?complex ditional‘?ve minutes. The solution was ?ltered with suc at a temperature ranging from about 0 to about 50° C. tion to obtain the solid diazonium salt melting with de We prefer to employ an inert solvent in carrying out the composition at a temperature of 85—87° C. The diazo' diazotization reaction and since the complex is essen nium salt was then coupled with 7.2 grams of 2~naphthol tially insoluble in‘nearly allpsolvents with which it does in 10% aqueous sodium hydroxide to obtain 11 grams not react, we’ mean by the term inert solvent, ‘a solvent of an orange azo dye havingamelting point of 134° C. for ‘the material, being diazotized which is inert insofar Now having described our invention, what we claim is: as _the complex is concerned,‘ and obviously‘ the inert solvent‘must be one with which the, material to be diazo 2. A’ processfor the production of a complex of bo tized‘ does not react but in which it‘ merely dissolves. 10 ron tri?uoride and dinitrogen trioxide having the for Suitable solvents‘ include chloroform‘, benzene, nitro mula BF3~N2O3 which comprises contacting dry gaseous benzene, carbon tetrachloride, etc, if the‘solvents do not boron tri?uoride withdry dinitrogen trioxide to produce react‘with the particular material being diazotized. a complex ofboron‘wtri?uoride and dinitrogen trioxide ‘The diazotization reaction is usually complete‘in 30 as a white amorphous solid. to 60‘minutes_and the insoluble diazom'um salt can eas 3. A process for the production of a complex of bo ily be isolatedgby ?ltration. The ‘salts are. stable and can ron tri?uoride and dinitrogen trioxide having the for be conveniently handled. Compounds which we. have mula Elia-N203 which; comprises contacting dry liquid diazotized include aniline, 2,6>dibromo-4-nitroaniline, 2,4 dinitrogen trioxide with gaseous boron tri?uoride and dinitroaniline, ,tribromoanil‘ine,‘ 2-chloroaniline, 4-chlo separating a complex ofvboron tri?uon'de and dinitrogen roaniline, 4-nitroaniline, 2,4-dinitro-1~naphthylamine, 2 20 trioxide as a White amorphous. solid. nitro-p-phenylene diamine, “and p-phenylene diamine. 4. Atpirocessfor the production of a complex of boron The dia‘zonium salts obtained can be heated to form tri?uoride and'dinitrogen trioxide having the formula ?uoro derivatives ‘of the‘ starting ‘aromatic nucleus or if Elia-N203 which comprises contacting dinitrogen tri the diazotization is carried out using benzene as a sol oxide with gaseous boron trifluoride in the presence of vent, sodium acetate can be.