Patented Dec. 30, ‘1952 2,623.04

UNITED STATES PATENT orricsg. 2,623,904 nrrao ALDEHYDES AND PRErAaArioN _ TPEREGF Curtis W. Smith, ‘Berke ley, Calif., assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application December 3, 1948, Serial No. 63,455 13 Claims. (Cl. 260-601) substituent group is directly linked to an- all This invention relates to organic compounds phatic carbon atom to which there is also direct and to a process for the preparation of organic ly attached an atom of hydrogen, nitro-aldehydes compounds. rather than nitro-alcohols, are produced. ' More particularly, the invention relates to The alpha-methylidene aldehydes are those nitrmaldehydes and to a process for the prepara aldehydes which have directly linked to the car tion of nitro-aldehydes. The invention also re bon atom in the alpha position relative to the lates to a new and unexpected reaction of ‘un formyl group a methylidene radical (CI-I2=),. saturated aldehydes with organic nitro com Thus, they are the alpha, beta-ole?nic aldehydes pounds whereby the nitro-aldehydes of the in in which the remaining valences of thecarbon vention may be prepared. atom in the beta position are satis?ed byatoms It has been discovered that nitro-aldehydes of hydrogen. The alpha-methylidene aldehydes may be prepared by condensing alpha-methyli may also be described by means of the formula dene aldehydes with nitro-substituted compounds wherein a nitro substituent group is directly linked to an aliphatic carbon atom to which there is also directly attached an atom of hydrogen. It is known from U. S. Patent 2,332,482 to Deger in which R is a hydrogen atom or a substituent ing et 2.1., October 19, 1943, that when croton group or atom other than hydrogen, for exam aldehyde is condensed with various nitro ple, a hydrocarbon radical, such'as an alkyl, aryl, paraf?ns in the presence of mildly alkaline cata cycloalkyl, aralkyl, or an alkaryl group. Par lysts there are obtained unsaturated nitro, ticularly available and preferred are the all alcohols. It also is well-known that saturated phatic alpha-methylidene aldehydes, such as aldehydes such as formaldehyde, acetaldehyde, acrolein itself and its alpha-alkyl substitution butyraldehyde, as well as various aromatic alde products, 1. e. z-propenal and the‘ 2-alkylprope hydes and even various halogen-substituted satu ,nals. Acrolein thus is represented by the fore rated aldehydes, when condensed with nitro going formula when R represents a hydrogen paraii‘ins in the presence of mildly alkaline cata atom. The alpha-alkyl acroleins, or the 2 lysts, react with the nitro-paraflins to form nitro alkylpropenals, are represented by the foregoing alcohols. Representative disclosures of processes formula when R. represents an alkyl group, within the latter category may be found in the .310 exemplary alkyl groups being methyl, ethyl, following patents; ' Fpropyl, isopropyl, butyl, secondary butyl, tertiary U. S. 2,132,330 to Vanderbilt, October 4, 1938 butyl, the pentyl groups, the hexyl groups, the U. S. 2,132,352 to Hass and Vanderbilt, October heptyl groups, the octyl groups, and analogous and homologous straight or branched chain alkyl 4, 1938 ' U. S. 2,132,353 to Bass and Vanderbilt, October groups. Representative aliphatic alpha-methyl idene aldehydes include in addition to acrolein, 4, 1938 ‘ alpha-substituted acroleins, such as methacro U. S. 2,135,444 to Vanderbilt, November 1, 1938‘ -‘ lein, alpha-‘ethacrolein, alpha-propyl acrolein, U. S. 2,139,120 to Hass and Vanderbilt, December alpha-isopropyl acrolein, alpha-isobutyl acrolein, 6, 1938 ' 40 Hass and Vanderbilt, December I alpha-t-butyl acrolein, alpha-pentyl acrolein, U. S. 2,139,121 to alpha-neopentyl acrolein and their homologs and 5, 1938 . - - U. S. 2,146,060 to Ellis, February '7, 1939 analogs. U. S. 2,231,403 to Wyler, February 11, 1941 __ The organic nitro compounds with which British 473,143, to I. G. Farbenindustrie Aktienge alpha-methylidene aldehydes are'condensed ac ‘_ cording to the invention to form nitro-aldehydes sellschaftbOctober 6, 1937- » ' ‘ . a nitro group (N02) directly linked'to - contain The nitro-aldehydes produced by the process of ‘an aliphatic carbon atom to which there‘ is also the invention are readily distinguishable from directly linked at least one atom of hydrogen. the nitro alcohols thus heretofore prepared. In ‘Because of their availability and the excellent view of the known reactions of saturated and .50 yields of desired products obtainable therefrom aromatic aldehydes, and even‘of the ole?nic alde the organic nitro compound ordinarily will be hyde, crotonaldehyde, with organic nitro com a nitro-para?in having at least one hydrogen pounds, it indeed was surprising to discover that, 'atom directly linked to the. carbon atom bearing when alpha-methylidene aldehydes are ' con the~ nitro group. Representative " nitro-para?ins 'densed according to the process of the invention which may be employed are nitro-methane, nitro --withenitro-substituted compounds’wh'er'éin a] nitro 2,623,904 3 ethane, l-nitrop'ropane, 2-nitropropane, l-nitro butane, 2-nitrobutane, I-nitrO-Z-methylpropane, Formation of undesired resinous or polymeric l-nitropentane, 2-nitropentane, 3-nitropentane, products may be further minimized or substan 1-nitro-3-methylbutane, l-nitro-Z-methylbutane, tially obviated by conducting the condensation in 2-nitro-3-methylbutane, 2-nitrooctane, 3-nitro the presence of any of the known polymeriza hexane, and analogous and homologous nitro tion inhibitors which prevent the polymeriza parailins. Although the nitro-paraf?ns will ordi tion of alpha-methylidene aldehydes. Only small narily be unsubstituted, nitro-paranins which amounts of polymerization inhibitor, if one is contain one or more non-interfering substituent employed, need be used. Based upon the com groups (examples thereof being aryl, cycloalkyl, bined weight of the reactants, as little as 0.01% alkoxy, carbohydro-carbyloxy, acyloxy, halogen, of the polymerization inhibitor may be employed etc.) may be reacted with alpha-methylidene al while as much as 10% or more may be used if dehydes according to the invention to produce desired. The optimum amount in any particu— correspondingly substituted nitro ~ aldehydes. lar case will be determined in part by the par While more than one nitro group may be pres ticular alpha-methylidene aldehyde that is to be ent in the nitro-para?in and while the nitro employed and in part upon the identity of the group or groups may be linked to either a primary polymerization inhibitor used. Representative or a secondary carbon atom, the secondary mono polymerization inhibitors or anti-oxidants which nitro-alkanes are particularly preferred, i. e., the may be employed include, without being limited nitro-alkanes wherein the carbon atom to which ‘ to, phenolic compounds, quinone , amines, nitro the nitro group is attached has directly bonded aryl compounds, alkylol amines, inorganic ma to it, in addition to the nitro group, one hydro terials such as elemental sulfur, selenium, cop gen atom and two carbon atoms. per, and compounds thereof, as Well as suitable According to the invention it has been discov organic compounds thereof. Hydroquinone is ered that nitro-aldehydes may be prepared in = highly effective as the polymerization inhibitor. high yields biy condensing a1plia~methylidene Other polymerization inhibitors which may be aldehydes with organic nitro compounds in which employed include, without being limited to, resor the nitro group is directly linked to an aliphatic sinol, pyrogallol, orcinol, guaiacol, ethanol amine, carbon atom having at least one hydrogen atom nitro phenol, nitroso phenol, and many others. directly bonded thereto, in liquid phase, prefer- ' For the preparation of the desired nitro alde~ ably in the presence of a mildly alkaline catalyst hydes it is essential to employ the two reactants and under conditions which minimize polymer in such proportions that there is present less ization of the alpha-methylidene aldehyde and than two mols of nitro compound per mol of the which minimize or prevent the formation of res alpha-methylidene aldehyde. The reactants inous products from the reactants employed. preferably are employed in substantially molecu The alpha-methylidene aldehydes are noted for larly equivalent proportions. The nitro com their great tendency to form polymers or resins, pound may be employed in moderate excess, say particularly in the presence of alkaline materials, up to about 1.2 mols per mol of the alpha-meth and for their tendency to condense with other ylidene aldehyde, although as the amount of the nitro compound is increased abovean amount compounds to form high molecular weight com 40 plex resinous or polymeric materials. The for equivalent to the alpha-methylidene aldehyde the mation of undesired resinous or polymeric mate ef?ciency of the process is reduced and reduced rials in the execution of the process of the pres yields of the desired nitro aldehydes are obtained. ent invention may be minimized or substantially The alpha-methylidene aldehyde may be pres obviated and formation of the desired nitro-alde ent in an amount greater than equivalent to the hydes may be obtained, by conducting the reac 45 organic nitro compound reactant, for example, tion in liquid phase in an inert organic solvent up to 4 or 5 or even more mols of the alpha-meth mediumv consisting essentially of one or more ylidene aldehyde per mol of the organic nitro organic solvents in which the reactants are solu compound. When the organic nitro compound ble. Aqueous media are undesirable because of reactant contains more than one hydrogen atom the great tendency of the alpha-methylidene a1 50 directly attached to the nitro-substituted carbon dehydes to form therein polymers or other un atom, nitro-polyaldehyde compounds may be pre- desired products, particularly in the presence pared. In the presence of an excess of the alpha— of basic substances. Any inert organic solvent methylidene aldehyde, two molecules of the which is av solvent for the reactants may be em alpha-methylene aldehyde may condense with ployed. Suitable solvents include, without be 55 one molecule of a primary nitro-alkane to pro ing limited to, ethers such as dimethyl ether, duce valuable nitro-dialdehydes of they typev of diethyl ether, dipropyl ether, diisopropyl ether, 4-alkyl-4-nitroheptanedials, and in the case of and homologs and analogs thereof as well as suit nitro-methane, even three molecules of the al able substitution products thereof; esters, such pha-methylidene aldehyde may react with each as. esters of carboxylic acids, for example, ethyl 60 molecule of the nitro-compound reactant. acetate, amyl acetate, methyl acetate, methyl Amounts of the alpha-methylidene aldehyde valerate, and like esters; alcohols, such as ethan greater than are required by the reaction are not o1, propanol, isopropanol, butanol, propylene gly essential, although they may be employed. Since col, trimethylene glycol, butylene glycol, as well excess aldehyde present tends to be converted to as. polyalkylene glycols; glycol mono- and di 65 polymeric materials and hence is lost, amounts ethers, which may be acyclic, such as mono- and ‘greater than theoretically required generally are dialkyl ethers of ethylene, propylene, trimethyl preferably avoided. ene, butylene and higher glycols, or cyclic, intra~ The reaction is favored by mildly alkaline con molecular others, such as dioxane, tetrahydro ditions as provided by the presence of an alka furan, tetrahydropyran, and the like. Hydrocar 70 line, or basic-reacting substance. Alkaline con bon solvents also may be employed, such as the densation catalysts may thus be employed. The normally liquid para?ins, the normally liquid alkaline condensation catalyst may be selected halogenated para?ins, and aromatic hydrocarbon from a Wide range and variety of materials. The solvents. oxides, hydroxides, and carbonates of the alka~ line earth metals, such as calcium oxide, barium . 25,23,904 ' manipulations. If the catalyst is one that is only -oxide, calcium hydroxide, calcium carbonate, slightly soluble in the reaction mixture, the reac strontium carbonate, strontium oxide, and bari tion mixture desirably may be agitated during >um carbonate, may be employed. The hydrox the reaction time in order to assure adequate ides and the alkaline salts of the alkali metals contact of the catalyst with the reaction mixture. may be employed. Thus, small amounts of the ‘ Other suitable means for affording intimate con hydroxides of lithium, of sodium, of potassium tact of the reaction mixture with an insoluble and even of rubidinum and of caesium, as well catalyst may be employed depending upon the as the carbonates thereof may be used as the con physical form of the catalyst, e. g.,“ whether .densation catalyst. Other alkaline materials or ?nely divided, in massive state, etc. If a solvent basic condensation catalysts which may be em ,10 is employed, the reactants may be mixed and the . ployed include, for example, organic amines such solvent added to the mixture, one reactant may as pyridine, tripropyl amine, benzyltrimethylam be added to the reaction mixture in the form of monium hydroxide, triamyl amine as well as ' a solution in the solvent and the other reactant basic-reacting salts such as disodium phosphate, added thereto or solutions of the two reactants ’ sodium borate, sodium acetate, and the'like. Po-r 15 in the same or in dissimilar solvents may be tassium carbonate, because of it mildly alkaline reaction and its limited solubility in the reaction mixed.The reactiontime required for completion' ‘ of mixtures employed (which limited solubility pre the reaction by which the desired nitro-alde cludes the presence of an excess in dissolved hydes are formed depends upon the particular form), is a highly efficacious condensation cata-V .20 reactants that are involved, the reaction tem lyst which may be employed. The amount of the perature, and upon the other conditions under alkaline condensation catalyst which may be em which the process is executed. The course of the ployed most effectively depends upon the particu reaction may be followed by withdrawing samples ‘lar reactants involved, the identity of the alka of the reaction mixture at suitable intervals‘ and line material or condensation catalyst and upon 25 subjecting them to analysis. Unless sufficiently the other conditions of reaction. In general, long reaction times are provided, inadequate . amounts from about 0.5 to about 5% by weight quantities of the desired nitro-aldehydes are ‘of the reactants are satisfactory in the case of formed while with excessively long reaction times the mildly alkaline agents, while in the case of polymerization or other undesired side reactions the more strongly alkaline agents, such as the may be favored. Under otherwise equal condi caustic alkalies, proportionally lesser amounts tions, the rate of reaction varies with the tem . desirably are employed under otherwise similar perature employed, or conversely, the required time varies inversely with the temperature. Gen conditions.The temperature atwhich the reaction is_ con erally speaking, the reaction will have progressed ducted may be about ordinary room tempera 35 substantially within a period of from about 2 tures. The condensation of the alpha-methyl hours to about 36 hours from its commencement idene aldehyde with the organic nitro compound depending, as aforesaid, upon'the particular con may be accelerated if desired by the application ditions and reactions involved. of heat. Temperatures as high as 100° C. may be After completion of the reaction the desired employed, although in order to minimize possible 40 product may be recovered from the reaction mix polymerization of the alpha-methylidene alde ture in any suitable manner. The ‘catalyst, if hyde, temperatures not over about 60° C. prefer present in the solid phase, may be removed as by temperature may be as 7 ably are employed. The ?ltration, sedimentation, centrifugation, by de low as desired. Since reduced temperatures re cantation of the liquid, or by other applicable temperatures below about 0° C. 45 means which will be apparent to those skilled in ‘ tard the reaction, _, ordinarily will not be employed. the art. If desired, traces of the catalyst dis The desired reaction may be effected by mix solved in the reaction mixture may be neutralized ing the two reactants in the presence of the alka as by addition of acid or as by washing the mix , line condensation catalyst, preferably in the pres ture with a solvent with which it is immiscible ence of an organic solvent, or in the presenceof 50 and in which the catalyst is soluble, e. g., water. a polymerization inhibitor or in the presence of The desired product may be recovered from the _' both an organic solvent and polymerization in reaction mixture by any suitable method, such hibitor, and by thereafter maintaining reaction as by fractional distillation, 'by extraction with conditions until the reaction has substantially selective solvents, by low temperature crystalliza progressed. A suitable amount of the alkaline 55 tion, or by other suitable methods. catalyst and approximately equimolar amounts Nitro-aldehydes which may be prepared ac of the alpha-methylene aldehyde and the or cording to the process of the invention are use ganic nitro compound to be reacted therewith ful as chemical intermediates and in a variety of ‘ may be mixed in an organic solvent medium and other uses. They are of interest as biologically - the mixture allowed to stand, with heating if de 60 active materials or as intermediates for the ' sired, until the reaction has substantially pro preparation of biologically active materials, such gressed. The amount of the solvent desirably as fungicides, insecticides and the like. .. They corresponds to at least about 50% of the com may be converted to products valuable as special bined weight of the reactants. There is no known solvents and they may be employed with advan 65 tage in the preparation of resins. upper limit to the amount of solvent that may bev used. It will be obvious, however, that exces The following examples will illustrate the prin sively large amounts will so dilute the reaction . ciples upon which the invention is based, with - mixture that practicable operation of the process out, however, vlimiting the invention as it is more A convenient, but not crit broadly de?ned in the hereafter appended , would not be feasible. claims. In the examples the parts are by weight. ‘ ical, upper limit to the amount of the solvent to, - be employed is about 10 times the combined ' weight of the reactants. .If the catalystis sol- ' EXAMPLE I _ mixture, once the reactants, ‘i uble inthe reaction 7 v ‘ 1 .There weremixed in a reaction vessel provided 1 thereaction catalyst proceeds and the without solvent necessityhave been for mixed, further the . with amechanical stirrer, 1600 parts of diethyl case-p04 ‘ether, 5356 parts of la-riitrcp'ropane, 280 parts of methacrolein ‘containing ‘about 0.01% of hydro vthe washed ?ltrate was distilled. {After-removal 'quinone,‘and~50 parts of ?nely ground anhydrous of ‘solvent ‘and a ‘forerun comprising unreacted vpotassium carbonate. The mixture was stirred acrol'ein'and unreacted 2-nitropropane, thecrude for 18 hours during which time the temperature product was separated as the fraction distilling was substantially at room temperature (20°C. to etween 75° C. and 100° C. under 0.5 -millimeters 30° -C_.). The resulting ‘mixture was removed of mercury pressure. Amount 24.5 parts, corre fr‘ot‘nthe reaction vessel and theex'c'e’ss or_»undijs sponding to a 35%conversion. The product ‘cut ‘solv'ed ‘potassium carbonate was‘r‘émjoved by?l was redistilled under ‘a ‘pressure ~of ‘about 03 itriatio‘nl The ?ltrate was then .fractionally "dis millimeters of ‘mercury and the heart out dis tilled. 'After ‘removal 'of low boiling'fo‘rerun, 'tilli'ng from 70_°'c. to 72°‘Cxwasao11eated. The there was_'collécted 503 parts of'a ‘slightly yellow product was ‘identi?ed as 4umethyl-i-4enitropen liquid distilling between 66° vC. "and 78° C._at_‘a t'an'al. pressure ‘of 0.14 mm. of'mer'cur'y. \ The low boil A sample of the product when analyzed was ing forerun was redistilled and there "was ‘col found to contain [19 5% C, 75% H and 9.5% N, lected besides ether, 20 parts of ‘unreact'ed meth 15 compared to values calculated for the formula acrolein and 30 parts ofvunreacted 2-ynitr'opro TheCaHuNOs 2,4-dinitrophenylhydrazone of 50.99% ‘C, 7.43% vH, derivative and 91.39% of the pane. The fraction distilling between 66° C.'and 78° C. under 0.14 mm. of mercury ‘pressure‘was 4-methyl-4-nitropentana1 was prepared and identi?ed as slightly impure 2,4-dimethyl-4‘-;ni found to melt after recrystallization from ethanol tropentanal. The fraction represented a 79% '20 at 130—130.5° C. and'to contain 21.4% ‘nitrogen ‘conversion of ‘product based on the reactants em compared to a calculated value of 121.5% ‘nitrogen. ployed andan 85% ‘yield of product base'd'o'n 're~ By repeating the 'foregoing'experiment but‘ em ‘act'ants consumed. A portion of the 2,4-di ploying a reaction time of 18 ‘hours and a tem methyl-4-nitropentanal was redistilled and a perature of about 25° C., a 42% conversion to heart out having the following properties was 25 product was obtained. collected: The compounds prepared in Examples I and (II are illustrative of a novel class of ni-tro-‘ald'e Boiling point__-_> ______--__-. 66-68" C. (0.14 mm. hydes which may be producedaccording to the 7 mercury pressure). processiof the invention by reacting nitroalkanes Refractive index (n ZO/D) 1.4551. 30 having the nitro group directly linked to a sec— Speci?c gravity ('20/4)_‘_-_. 1.063. Analyses: ondary carbon atom with alphaémethyliden‘efali phatic aldehydes. The novel class of nitro-'-alde~ 52.5% 0. hydes to which the invention relates/may be de Found _____V-___-__‘__- 8.2% H. ?ned - by means of the generic structural‘ formula 8.77% N. Caluculated for 52.8% C. (37H13NO3 ______._.l 8.2% H. 8.80% N. The 32,4-dinitrophenylhydrazone derivative of in which each R‘represents a hydrocarbon group ‘the ‘2.4-dimethyl'-4-nitropentanal was prepared and R’ representsthe hydrogen atom or an alkyl and ‘found to melt at 135.5—136.5° C. after re group. Novel compounds corresponding in struc crystallization from ethanol. It was found to ture to this formula'm'ay be prepared in and ‘contain 20.6% nitrogen compared to a theo ?cient ‘manner ‘by reacting secondary nitro fre'ti'calv'alue of 20.64% calculated for the formula alkanes which may be unsubstituted or which CiaHrrNaOs. 45 may also have attached to carbon atoms of the EXAMPLE II alkane residue one or more cyclic or acyclic hy ~2-nitropropane and acrolein were reacted by drocarbon substitutent groups, ‘with aliphatic ~~mixing 45 parts of 2 -nitropropane with 28 parts alpha-'methylidene aldehydes ‘represented by ~of‘acro1ein containing about 0.01% by weight of :acrolein ‘and its alpha-‘alkyl substitution prod hydroquinone, in 80 parts of diethyl ether in V50 ' Of particular interest are the aliphatic 'm'tr'o -'aldehy'des "which ‘correspond in ‘structure ‘to iwhichetherewas‘ suspended 10 parts of anhydrous the structure represented by the foregoing ‘.ge ipotassi-um carbonate. The reaction was ' effected bygentl-y warming the mixture to 35° C. to 40° C. neric'equation. 'Preferred products mayalso be and maintaining it at this ‘temperature for two described by means‘of the formula 65 hours while stirring. The reaction "vessel was ‘0,312,. + 1 (LE2, + 1 equipped with a well cooled re?ux ‘condenser to .prevent excess loss of‘the'ssolve'nt. 'At the end - of the "two -hour reaction period the mixture was ?ltered to remove ‘excess potassium v‘carbonate. in which n represents .a positive int eger and y The ?ltrate was washed by shaking with several 60 represents 0 or a positiveinteger. 'Further prod portions I of ’ dilute aqueous hydrochloric 1'acid and ucts corresponding instructure to the formula are disclosed in thelfollowing table: Table I

, nlpha-lviethylidelie = Aldehyde Réactan't Nitroalkane Reactant a Product

v V4-Methyl-4-nitrooctanal.47Methyl-4-nitrohexanal. = 2,4-Dimethyl-4-nitrohexanal. DOIIIIIIIIIIIII ______.. I2,4-D1methyl4-nitrooctanal. ~41pha-ethyl-acrolein... _‘lit-Butyl-2-methyl4~uitrohexanal.4~Methyl-z-ethylanitropentanal. Alphe-pentyl acrolei pha~hexyl acrolein 'g-lvleth yl-21-rlr9py1-4-1l1itrodecafial. _ A4-Methyle2-hexyl#4~nitrodecanal.- sopropy - ~1son1ay -2-penty Ami'trobutbinh I . 2,628,904 . 10 , solution in an inert liquid organic solvent in the The disclosed novel nitro-aldehydes may be pre presence of an alkaline condensation catalyst pared by reacting according to the method illus and a small amount not over about 10% by Weight trated in the preceding examples the indicated of the reactants of a phenolic antioxidant under nitro-alkanes with alpha-methylidene aldehydes substantially anhydrous conditions at a tempera appearing in the table. Homologous and anal ogous nitro-aldehydes may be prepared in similar ture of from about 0° C. to about 100° C. and re manner from homologous and analogous nitro covering said nitroaldehyde. ' , compounds and holomologus and analogous 4. The process for the ‘preparation of 4,4-d1 alpha-methylidene aldehydes. alkyl-‘l-nitrobutanal which consists of mixing one The novel nitro-aldehydes thus illustrated and 10 mole of acrolein and not over about 1.2 moles of secondary nitroalkane in solution in a substan more broadly de?ned by the generic formula have tially anhydrous inert liquid organic solvent in desirable properties which could not have been the presence of an alkaline condensation catalyst foreseen from the properties of heretofore known nitroaldehydes. Their desirable properties ap and a phenolic antioxidant at a temperature of 15 from about 0° C. to about 100° C. and after re pear to be due in part to the direct attachment action has occurred isolating said 4,4-dialkyl-4 of the nitro group to a tertiary carbon atom, which carbon atom is in the gamma position to nitrobutanal. the formyl group. While secondary nitro 5. The process for the preparation of 4,4-di alkanes containing from three to as many as alkyl-4-nitrobutanal which consists of condens 20 ing acrolein with one mole of secondary nitro eighteen carbon atoms and alpha-methylidene alkane per mole of the acrolein in solution in a aldehydes containing from three to as many as substantially anhydrous inert liquid organic sol twelve carbon atoms may be employed for the vent in the presence of an alkaline condensation preparation according to the process of the in vention of novel nitr-o-aldehydes represented by catalyst and a small amount not over about 10% 25 by weight of the reactants of a phenolic anti the last-given generic formula, the preferred oxidant at a temperature of from about 0° C. to products are those wherein the sum of the num about 60° C. and recovering said 4,4-dialkyl-4 bers represented by n is from 3 to 12, inclusive, nitrobutanal. and the integer represented by y is 10 or less. 6. The process for the preparation of 4,4-di The novel nitro-aldehydes provided by the inven alkyl-Z-methyl-4-nitrobutano1 which consists tion have a strong bacteriocidal action and hence of mixing one mole of methacrolein and not over are useful as ingredients for the compounding about 1.2 moles of secondary nitroalkane in solu of improved antiseptic, bacteriocidal, and bac tion in a substantially anhydrous inert liquid or teriostatic compositions. They may be condensed ganic solvent in the presence of an alkaline con with phenols, with urea, and allied substances densation catalyst and a phenolic antioxidant at to form valuable high-molecular weight poly a temperature of from about 0° C. to about 100° mers and resins. Additionally, the novel nitro C. and after reaction has occurred recovering aldehydes thus provided are of value, because of said 4,4-dialkyl-Z-methyl-4-nitrobutanal. the attachment of the nitro group to a tertiary '7. The process for the preparation of 2,4-di— carbon atom, which carbon atom is gamma with alkyl-4-nitropentana1 which consists of condens respect to the formyl group, as intermediates for s the preparation of compounds which may be em ing an unsubstituted alpha-alkyl acrolein with ployed as improved solvents, as improved biolog one mole of 2-nitroalkane per mole of the alpha ically active compounds, and in many other uses. alkyl acrolein in solution in a substantially an hydrous inert liquid organic solvent in the pres I claim as my invention: 1. An aldehyde having the structure repre ence of an alkaline condensation catalyst and a 45 phenolic antioxidant at a temperature of from sented by the formula about 0° C. to about 60° C. and recovering said 2,4-dialkyl-4-nitropentanal. ’ 8. The process for the preparation of 2,4-di methyl-d-nitropentanal which consists of mix ing about equimolar quantities of methacrolein in which each R represents a hydrocarbon group and 2-nitropropane in solution in diethyl ether and R’ represents one of the class consisting and maintaining the solution in contact with of hydrogen and alkyl. added solid potassium carbonate in the presence 2. The process for the preparation of a nitro of added hydroquinone at about room tempera aldehyde having a nitro group substituted in the ture for about 18 hours, and distilling to isolate gamma position relative to the aldehyde group said 2,4-dimethyl-ll-nitropentanal. which consists of condensing one mole of a nitro 9. The process for the preparation of ‘i-methyl substituted organic compound having both the 4-nitropentanal which consists of mixing about nitro group and not less than one atom of hydro equimolar quantities of methacroleinv and 2 gen directly bonded ‘to one and the same carbon 00 nitropropane in solution in diethyl ether and atom with one mole of an unsubstituted alpha heating the solution in contact with added solid methylidene aldehyde in solution in a substan potassium‘ carbonate in the presence of added hy tially anhydrous inert liquid organic solvent in droquinone at about 35° C. to 40° C. for about 2 the presence of an alkaline condensation catalyst hours, and distilling to isolate said 4-methyl-4 and a polymerization inhibitor at a temperature 65 nitropentanal. of from about 0° C. to about 100° C. and recover 10. 4,4-dihydrocarbon-‘ii-nitrobutanal. ing said nitroaldeliyde. 3. The process for the preparation of a nitro l1. 4,4-dihydrocarbon - 2 - methyl - 4 - nitro aldehyde having a nitro group substituted in the butanal. gamma position relative to the aldehydo group 70 l2. 2,41dialkyl-4-nitropentanal. which consists of condensing one mole of ,a nitro 13. 2,4-dimethyl-4-nitropentanal. alkane having both the nitro group and not less CURTIS W. SMITH. than one atom of hydrogen directly bonded to one and the same carbon atom‘ with one mole of an unsubstituted alpha-methylidene aldehyde in 75 (References on following page) 11 12 REFERENCES. CITED OTHER, REFERENCES The following references are of recordv in the. ?le of this patent: vShaw, Rec; Trav; Chim'., v01. 1.7,. pp. 50-65 (per bicularly 64i 65 )z, (18.9.8). . UNITED STATES PATENTS Degering; ‘Outline,- of Organic. Nitrogen‘ Com Number Name Date pounds“ (1945)’, pp. 73, 74, University Litho 2,332,482 Degering et aL _____ Oct. 19,, 1943' printers; 2,355,402 Sussman ______Aug,v 8, 19.44 Fort: et. al.,,J.‘ Chem. Soc; (London), (194‘8),v pp:. 2,475,996 Smith ______July 12, 1949 1907-1909.