Patented Apr. 16, 1946 - 2,398,481

UNITED STATES PATENT OFFICE 2,398,481 PROCESS FOR, CATALYZED ABNORMA, -N ADDITION REACTIONS William E. Waughan and Frederick F. Rust, Berkeley, Calif., assignors to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application February 23, 1942, Serial No. 432,049 8 Claims. (C. 204-163) This invention relates to an improved method attached thereto, so that, as clearly brought out for the addition of hydrogen halides, hydrogen by Jones and Reid (Journal American Chemical sulfide and/or mercaptains to symmetrical or un Society, volume 60, pp. 2452-2455) the addition symmetrical organic compounds containing One takes place according to Markownikoff's rule. or more unsaturated linkages of aliphatic char Therefore, when terminally unsaturated olefins acter. In One of its more Specific embodiments, are thus reacted with hydrogen sulfide, the re the invention pertains to a novel method of action product predominates in secondary mer effecting a controlled reaction between a hydro captains and/or secondary thio-ethers. When gen halide (particularly hydrogen bromide), hy the unsaturated organic compounds have been drogen sulfide or a mercaptan, and unsymmetri O reacted with the mercaptains at the aforemen cal organic compounds containing at least one tioned elevated temperatures, the Sulfur of the unsaturated linkage of aliphatic character, i. e. mercapto radical attached predominantly to the an olefinic or acetylenic bond, to produce ad unsaturated carbon atom holding the most hy dition products of predetermined character. drogen atoms so that this addition was contrary It is known that hydrogen halides may be 5 to the course Suggested by the Markownikoff added to unsaturated hydrocarbons and to rule. This condition was designated as 'ab various unsaturated derivatives thereof. In fact, normal' addition on the assumption that mer. in 1870, Markownikoff stated that "if an unsym captains should add like halogen acids. With metrical hydrocarbon combines with a halogen reference to the addition of mercaptains to un acid, the halogen adds to the carbon atom with 20 Saturated organic compounds, it is known that fewer hydrogen atoms, i. e. to the carbon atom the abnormal addition may be catalyzed by free which is more under the influence of other carbon Oxygen, air, ozone, peroxides, ascaridole and the atoms.' The same investigator further deter like, while compounds of the type of hydroquin mined that when a hydrogen halide is added to one and piperidine act as reaction inhibitors. a halogenated unsaturated compound such as 25 Warious methods have been proposed for Con vinyl chloride or a chlorinated propylene (i. e. trolling the addition of hydrogen halides so as to unsaturated hydrocarbons wherein. One of the to form reaction products in which hydrogen unsaturated carbon atoms carries a halogen halide has been added contrary to the above atom, or wherein these unsaturated carbon atoms Markownikoff rule. For instance, it has been contain dissimilar numbers of halogen atoms 30 proposed to effect the hydrohalogenation re directly attached thereto), the halogen atom of action in the presence of various peroxides as the hydrogen halide will add to the double bonded well as Of compounds of the type of Oxygen, (unsaturated) carbon atom which carries the air, or ozone, all of which tend to form peroxides greater number of halogen atoms, while the hy when contacted with unsaturated hydrocarbons. drogen atom of the hydrogen halide molecule Also, it has been found that hydrogen bromide attaches to the adjacent unsaturated carbon may be added to the unsaturated organic com atom. The above type of hydrohalogenation is pounds in a manner contrary to Markownikoff's termed “normal' to distinguish it from the 'ab rule by effecting the reaction under the deliber normal' addition of a hydrogen halide, in which ate influence of ultra-violet radiations, particu latter case the hydrogen and halogen atoms are 40 larly those having wave-lengths below about added in positions which are interchanged with 2900 to 3000 Angstrom units. Similarly, accord respect to addition according to the above-out ing to a recent discovery, hydrogen sulfide may lined Markownikoff rule. be added to unsaturated organic compounds, It is also known that mercaptains and thio contrary to the course suggested by the Mar ethers may bef produced by reacting hydrogen kownikoff rule, by effecting the reaction at normal sulfide or a suitable mercaptain with an unsatur temperatures or even at considerably lower tem ated organic compound, e. g. unsaturated hydro peratures, under the deliberate influence of ultra carbon, at elevated temperatures in the approxi violet radiations having wave-lengths of below mate range of from 200° C. to 750° C. In some about 2900 to 3000 Angstrom units. It is known cases such reactions were effected at Superat that the presence of peroxides or of peroxide mospheric pressures. When hydrogen sulfide is forming compounds in unsaturated organic con reacted with unsaturated Organic compounds pounds, e. g. unsaturated hydrocarbons, is un under the outlined conditions, the sulfhydryl desirable. As to the abnormal addition of hy group attaches to the unsaturated carbon atom drogen halides such as hydrogen bromide or of containing the lesser number of hydrogen atoms 55 hydrogen sulfide and/or mercaptains to unsatu 2 2,898,481 rated organic compounds under the deliberate p. 646 (1904)) concerning the addition of mel'- influence of ultra-violet rays, such processes captains to double bonds. necessitate the use of special equipment which The unsaturated organic compounds which is capable of transmitting rays of the defined low may be treated according to the process of this wave-lengths. In other words, in order to effect invention include hydrocarbons containing One the desired reaction it is necessary to employ or more olefinic and/or acetylenic linkages. Ex reaction vessels and/or lamps of quartz or other amples of such hydrocarbons are ethylene, pro suitable materials, e. g. calcium fluoride, which pylene, butene-1, butene-2, isobutylene, pen are capable of transmitting the defined short tene-1, pentene-2, hexene-1,4-methyl-pentene-1, wave-lengths of 2900 to 3000 Angstrom units, and O 4,4-dimethyl-pentene-1,4-methyl-pentene-2, oc below. tene-1, decene-1, cetene-1, styrene, cyclohexene, It has now been discovered that unsaturated 3-methyl-cyclohexene, 1,4-diphenylbutene-2, bu organic compounds of the class more fully de tadiene-1,3, pentadiene-1,3, pentadiene-1,4, hex scribed hereinbelow may be reacted with hydro adiene-1,5, hexadiene-1,4, , acetylene, propyne, gen halides, and more particularly hydrogen 5 butyne-1, pentyne-2, hexyne-1, cetyne-1, octyl bromide, or with hydrogen sulfide or mercaptains, acetylene, phenyl-acetylene, cyclopentadiene, to effect directional addition thereof via the and the like. The above compounds, and their above-defined 'abnormal' addition, this reaction various homologues, may be substituted in the being effected without the necessity of resorting nucleus and/or in the substituents in various der to high temperatures and/or elevated pressures, 20 grees. For instance, the unsaturates may con and in the absence of undesirable peroxides or tain one or more halogen atoms attached to Sat peroxide-forming compounds. It has also been urated and/or unsaturated carbon atoms. Rep discovered that this reaction according to this resentative examples of these compounds are: invention may be effected without the necessity vinyl halides, allyl halides, crotyl halides, meth of employing any special equipment or apparatus allyl halides, and the like. Other examples of capable of transmitting very low ultra-violet Substituted unsaturated hydrocarbons are methyl rays, such as radiations having wave-lengths of acrylate, methyl methacrylate, divinyl ether, 2900 to 3000 Angstrom units, and below. Accord diallyl ether, dimethallyl ether, and the like. ing to the present process, this abnormal addi A particularly suitable group of Organic comi tion of mercaptains, hydrogen sulfide, and/or hy 30 pounds which may be reacted with mercaptains, drogen halides such as hydrogen bromide, is at hydrogen sulfide or hydrogen bromide via ab tained by effecting the reaction under irradiat normal addition comprises the compounds, and ing conditions (and particularly under the de particularly the hydrocarbons, in which the un liberate influence of rays which will not other Saturated linkage is in terminal or alpha posi wise dissociate any one of the reactants), and 35 tion. Also, aliphatic hydrocarbons and their var in the presence of certain catalysts having defi ious substituted derivatives, e. g. halo-substituted nite and specific characteristics which promote derivatives, containing unsaturated linkages both the abnormal addition but the presence of which in alpha and omega positions (i. e. terminal posi tions), may be readily reacted with the above in the unsaturated organic compounds is not det 40 outlined compounds, via abnormal addition, to rimental. Generally speaking, these catalysts produce compounds in which both terminal car or reaction sensitizers comprise carbonylic com bon atoms have halogen, sulfhydryl, or mercapto pounds which absorb light and which may thus radicals attached thereto. Another group of or be decomposed photo-chemically by radiations ganic compounds which may be employed as the having wave-lengths of about 2900 to 3000 Ang 45 primary material comprises or includes organic strom units and above. Compounds wherein an olefinic linkage is in non It has also been discovered that catalysts or terminal position between two carbon atoms hav Sensitizers of the class more fully described here ing a dissimilar number of hydrogen atoms at in and consisting of or comprising carbonylic tached to each of said unsaturated carbon atoms compounds of the type defined hereinbelow will 50 due, for example, to various Substituents at catalyze and control the reaction between an tached thereto. For instance, the double bond unsaturated organic compound and a mercaptain, may be between two carbon atoms which are of hydrogen sulfide or a hydrogen halide such as secondary and tertiary character, respectively. hydrogen bromide, so that the reaction will oc Another example is a compound in which the un cur via the so-called 'abnormal’ addition at Or 55 Saturated carbon atoms are both primary or both dinary or even subnormal temperatures and with Secondary, but have unequal numbers of halogen out the necessity of employing special equip atoms, such as chlorine, bromine, fluorine and/or ment or apparatus which will transmit ultra-vio iodine atoms attached to them. let radiations having wave-lengths of 2900 to Although the above unsaturated organic com 3000 Angstrom units, or below. 30 pounds may be reacted via abnormal addition with Broadly stated, the present invention resides other hydrogen halides, it has been discovered in a photo-chemical process of effecting the ad that these unsaturates may be most readily re dition of suitable mercaptains, hydrogen sulfide acted, in accordance with the process of the pres or hydrogen halides in the presence of carbonylic ent invention, with hydrogen bromide to produce Compounds and under the deliberate influence s brominated compounds wherein the bromine of light capable of photo-chemically dissociat atoms have been added contrary to the Mar ing said catalyst or sensitizer, this reaction being kownikoff rule. As to the mercaptains which may effected at normal temperatures, i. e. in the be used, any sufficiently stable mercaptain is suit neighborhood of about 25° C. to about 15° C. able as a reactant to be employed in the photo or even considerably lower temperatures. As O chemical addition thereof to the above-defined stated, this photo-chemical addition, according class of unsaturated organic compounds. A suit to the present invention, occurs contrary to the able mercaptain may contain one or more sulf course Suggested by Markownikoff for the addi hydryl groups or radicals, and be of alkyl, aralkyl, tion of hydrogen halides, and in accordance with alkenyl, aralkenyl or aryl character. The mer the rule proposed by Posner (Berichte, vol. 38, 75 capto redical may be linked to an aliphatic or an 2,898,485 V 3 aromatic carbon atom. In the majority of cases tures of about 25 C., is preferably effected at tem it is preferable to employ the normal or iso alkyl peratures which are even below 0°C. Also, it was chain mercaptains of primary, secondary or terti discovered that the abnormal addition of mer ary character, particularly those contained or de captains, hydrogen sulfide or hydrogen halides rived from petroleum and petroleum products. (e. g. hydrogen bromide), when the reaction is The methyl, ethyl, butyl, amyl, hexyl, heptyl, effected under the influence of the above-defined octyl and the like mercaptains, as well as their class of catalysts or sensitizers, proceeds regard homologues, analogues and substitution products, less of the presence or absence of a liquid film in may be employed with excellent results. Another the reaction zone. Although the reaction de group of mercaptains which may be employed as 0. scribed herein may be promoted or effected by one of the two reactants comprises or includes using the whole range of ultra-violet radiations, the dimercaptains, and particularly the poly it has been pointed out above that the presence methylene dimercaptains of the general formula of the defined catalysts or sensitizers (which, in HS (CH2) nSH. This group of mercaptains may be cidentally, do not have a detrimental effect on reacted with, for example, aliphatic hydrocarbons 5 the reactants) eliminates the necessity of using containing a plurality of unsaturated linkages to radiations having very short wave-lengths. In produce thio-ethers having a high molecular other words, whereas abnormal addition of, for Weight. example, hydrogen bromide to an unsaturated or As stated, the substances which may be used as ganic compound would require ultra-violet radia catalysts or sensitizers for the above-Outlined re 20 tions having wave-lengths of below about 2900 action in which mercaptains, hydrogen sulfide or to 3000 Angstrom units, the addition of even hydrogen halides are added via abnormal addi Small amounts of a compound of the class of cat tion, comprise the carbonylic compounds, and alyst or sensitizer defined above permits effective particularly those which may be dissociated or addition even when the radiations have longer decomposed photo-chemically by means of rays 25 wave-lengths, provided such rays will cause the having wave-lengths of about 2900 to 3000 Ang initial dissociation of the catalyst or sensitizer, strom units, and longer. Without any intention thereby initiating the chain mechanism, and at of being limited by the compounds enumerated the same time directionally controlling the addi herein, it may be stated that representative com tion reaction. pounds of this class include: aliphatic and aro 30 The abnormal reaction according to the present matic ketOnes, such as acetone, methyl ethyl ke process may be effected in a batch, intermittent tone, methyl n-propyl ketone, methyl isopropyl or continuous manner. When the process is exe ketones, diethyl ketone, ethyl n-propyl ketone, cuted batchwise, the reactants, together with a methyl n-butyl ketone, dipropyl ketone, aceto suitable amount of the catalyst or sensitizer of phenone, and their homologues; aldehydes, such 35 the defined class, may be conveyed under any as acetaldehyde, propionaldehyde, isobutyralde suitable or optimum pressure and temperature. hyde, benzaldehyde, and the like, and their hom into a suitable container which is then illumi ologues; and acid halides, for example, acetyl nated, preferably with ultra-violet light, for a bromide, propionyl bromide, and the like. It is to period of time sufficient to effect the desired addi be understood that there is no intention of con 40 tion reaction. Although containers of quartz or tending that all carbonylic compounds which are the like may be employed, so as to permit light dissociable by light may be employed equally effec waves of between 2900 and 3000 Angstrom units tively as catalysts or sensitizers for the described therethrough, it is possible to employ ordinary abnormal addition of mercaptains, hydrogen sul glass or Pyrex glass, since wave-lengths passing fide or hydrogen halides, e. g. hydrogen bromide. 45 through this type of glass will also dissociate the For example, some of these carbonylic compounds, sensitizer or catalyst and thus initiate and effect in order to be dissociated, may require radiations the desired reaction. Although there is no intention of being limited of much shorter wave-lengths than those neces sary for the decomposition of other carbonylic by any details therein, the following illustrative compounds. Also, the rate of chain initiation of 50 examples represent specific embodiments of the some carbonylic compounds, although they may present invention. be readily decomposed photo-chemically by radia Eacom.ple I tions of wave-lengths above 2900 Angstrom units, is considerably slower than the rate of chain in Pure propylene, which was carefully fraction itiation of other carbonylic compounds. This may 55 ated to separate it from other gases, was intro be due to steric hindrance or even resonance in duced into a Pyrex glass container which was first the radical formed during the decomposition. subjected to a high vacuum to remove substan Nevertheless, it may be generally stated that all tially all of the gases therefrom. The propylene carbonylic compounds, and particularly the ke gas was introduced until the pressure in the con tones, aldehydes and acid aldehydes, which are 80 tainer was equal to 102.3 mm. of mercury pres capable of being dissociated by light having wave sure. Thereafter hydrogen bromide gas was in lengths of about 2900 to 3000 Angstrom units, and troduced into the same container for an addi longer, may be effectively used as catalysts or tional 102.7 mm. of nercury pressure. The mix Sensitizers for the desired abnormal addition re ture was maintained at a temperature of about action. 65 25° C. and was subjected to ultra-violet radia The abnormal addition reaction between the tions from a quartz mercury lamp. Although this defined compounds according to the process of the irradiation was continued for about 25 minutes, present invention may be effected in the vapor or the pressure in the container remained substan liquid phase, or in a two-phase liquid-vapor sys tially unchanged, thus indicating that substan tem. Since the abnormal addition reaction occurs 70 tially no reaction occurred. On the other hand, photo-chemically, or under the influence of cat when acetone, in an amount of 2.5 mol percent, alysts or sensitizers which are dissociated to pro was added to propylene and hydrogen bromide, duce radicals which initiate the reaction, no heat and the mixture was then subjected to the same ing is necessary. In fact, in many instances the treatment and under the same conditions as those reaction, although it may be realized at tempera 75 described above, the pressure at the end of about 4. 2,898,481 30 minutes dropped down to approximately 115 compounds. It was then found that about 75% mm. of mercury pressure, thus indicating that the of the propylene reacted via abnormal addition, presence of the small amount of acetone caused the reaction product consisting of about 80 the reaction of about 80% of the propylene with weight percent of normal propyl mercaptain and the hydrogen bromide. An analysis of the reac about 20 weight percent of di-n-propyl Sulfide. tion product showed that it was predominantly Without any intention of being limited by any normal propyl bromide, i.e. a product of abnormal theory of the case, it is believed that the illumi addition. nation of the reaction mixtures containing the Eacample II carbonylic compounds described above causes the Equimolecular amounts of propylene and hy 0 formation of radicals by the decomposition of drogen bromide were mixed together with acetone the carbonylic compound. These radicals in turn in an amount equal to 0.85 mol percent, the gas react with the hydrogen bromide to liberate free eous mixture being then subjected in a Pyrex bromine atoms which in turn react with the un glass container at a temperature of about 25 C. saturated organic compound. Therefore it is to radiations from a quartz mercury lamp for a 5 apparently possible to catalyze the above reaction period of about five minutes. The analysis of the by introducing Small amounts of bromine. How reaction product showed that about 60% of the ever, this compound usually results in a reaction propylene was hydrobrominated, thus forming a product containing excessive proportions of the product having an index of refraction equal to corresponding di-bromide. No 1.4340, thus showing that this product was s Although the above experiments were con predominantly normal propyl bromide. ducted with hydrogen sulfide and hydrogen bro A similar experiment was conducted in which mide, it is to be understood that the invention the acetone was employed in an amount equal to is applicable to the abnormal addition of hydro about 9.0 mol percent. At the end of five minutes gen halides as well as mercaptains. Of the halides, irradiation, approximately 85% of the propylene 25 however, the invention finds particular appli was found to have been hydrobrominated to nor cability to the reactions involving the addition of mal propyl bromide. In this connection it must hydrogen bromide. Also, although propylene was be noted that generally the presence of relatively used in the above examples, the present inven large amounts of acetone form a somewhat un tion may be applied to the treatment of the whole stable condensation product which is believed to 30 class of unsaturated organic compounds described be the hydrobromide of mesityl oxide, this prod in greater detail hereinabove. uct apparently not being dependent for its for We claim as our invention: mation upon any illumination. The compound 1. In a process of producing normal propyl readily evolves hydrogen bromide upon heating. bromide, the steps of adding acetone to hydrogen 35 bromide and propylene and effecting the reaction Eacample III between said propylene and hydrogen bromide in a gaseous State at a temperature not in excess Pure propylene was introduced into an evacu of about 25° C. and under the deliberate influence ated Pyrex glass container until the pressure in of radiations above 3000 Angstrom units but the container was equal to 101.6 mm. of mercury 40 capable of dissociating acetone. pressure. Thereafter hydrogen bromide gas was 2. In a process of producing normal propyl introduced into the same container for an addi bromide the steps of adding acetaldehyde to hy tional 100.7 mm. of mercury pressure. After the drogen bromide and propylene and effecting the addition of acetaldehyde in an amount equal to reaction between said propylene and hydrogen about 6.9 mm. the mixture was subjected, at a 45 bromide in a gaseous state at a temperature not temperature of about 25 C. and for a period of in excess of about 25° C. and under the deliberate about three minutes, to ultra-violet radiations influence of radiations above 3000 Angstrom from a quartz mercury lamp. The drop in pres units but capable of dissociating acetaldehyde. sure indicated that approximately 60% of the 3. In a process of producing normal propyl propylene was hydrobrominated via abnormal ad 50 bromide the steps of mixing hydrogen bromide, dition. It is to be noted that the illumination of propylene and acetone and effecting the reaction a mixture of propylene and hydrogen bromide for at a temperature not in excess of about 25° C. a period of 25 minutes in the absence of the and under the deliberate influence of radiations acetaldehyde caused substantially no drop in above 3000 Angstrom units but capable of disso preSSure, ciating acetone. Eacample IV 4. In a process of effecting abnormal hydro Propylene and hydrogen sulfide were intro halogenation by the addition of hydrogen halide duced in a liquid State and in equal volumetric to an aliphatic hydrocarbon containing an alpha proportions into a Pyrex glass reactor. The re unsaturated linkage the steps of adding an ali action vessel was then Sealed and illuminated for 30 phatic ketone to the reaction mass and effecting a period of about six minutes by radiation ema the reaction in the absence of peroxides, at a nating from a quartz mercury lamp. The reactor temperature not in excess of about 25 C. and was maintained at a temperature of about 0' C. under the deliberate influence of radiations above An analysis of the Contents from the reactor 3000 Angstrom units but capable of dissociating showed that only about 4% of the propylene re the aliphatic ketone. acted. 5. In a process of effecting an abnormal hydro Eacample V halogenation by the addition of a hydrogen halide to an aliphatic hydrocarbon containing an alpha The experiment described in Example IV was unsaturated linkage the step of adding an alde repeated. However, prior to the sealing of the re 70 hyde to the reaction mass and effecting the re actor, acetone was added in such an amount that action photochemically, in the absence of perox the volumetric ratio of propylene, hydrogen Sull ides and under the deliberate influence of radia fide and acetone in the reactor was 7.4:7.4:1. tions above 3000 Angstron units but capable of After the six-minute illumination the reaction dissociating the aldehyde. mixture was distilled to evaporate the unreacted 75 6. In a process of effecting abnormal hydro 2,898,481 5. halogenation by the addition of a hydrogen acid halides and effecting the reaction photo halide to an unsaturated hydrocarbon contain chemically, in the absence of peroxides and under ing an unsaturated linkage between two carbon the deliberate influence of radiations above 3000 atoms having a dissimilar number of hydrogen Angstron units but capable of dissociating said atoms attached thereto, the steps of adding a carbonylic compound. carbonylic compound selected from the class Con 8. In a process of reacting propylene with hy sisting of ketones, aldehydes, and acid halides drogen bromide wherein the reaction would ordi to the reaction mass and effecting the reaction narily occur via normal addition to produce pre photochemically, in the absence of peroxides and dominantly isopropyl bromide, the improvement under the deliberate influence of radiations above O which comprises directionally controlling the re 3000 Angstrom units but capable of dissociating action to produce predominantly normal propyl the carbonylic compound. bromide by adding a minor amount of acetone 7. In a process for effecting reactions via ab to the reactants and subjecting the mixture at normal addition the steps of reacting an un a temperature not in excess of about 25° C. to the Saturated organic compound containing an un 5 action of light having Wave-lengths above 3000 Saturated linkage between two carbon atoms hav Angstrom units but capable of dissociating the ing a dissimilar number of hydrogen atoms ate acetOne. tached thereto, with a hydrogen halide in the WAM E. WAUGEAN. presence of a carbonylic compound selected from FREDERICK F. RUST. the class consisting of ketOnes, aldehydes and 20