Patented July 4, 1944 2,352,671 UNITED STATES PATENT OFFICE 2,352,671. Y. REACTION OF FORMALDEHYDE WITH ACRYLONTRE AND PRODUCT Joseph Frederic Walker, Lewiston, N. Y., assign or to E. I. du Pont de Nemours & Company, Wilmington, Del, a corporation of Delaware No Drawing. Application May 3, 1943, Serial No. 485,494 4 Claims. (C. 260-464) This invention relates to the reaction of form of formaldehyde, the compound reacting in the aldehyde and its polymers which function in form of its hydrate i.e., chemical reactions as the equivalent of form aldehyde with unsaturated compounds, more particularly with acrylonitrile (vinyl cyanide). BC It is also concerned with the new chemical com Yoh pounds produced thereby. It is convenient to tutilize the aqueous 37% solu When formaldehyde, or a polymer of formal tion of formaldehyde commercially available, al dehyde equivalent in chemical reactions to form though any other formaldehyde solution of any aldehyde, such as paraformaldehyde, is reacted 10 available concentration may be employed. As in an aqueous reaction mixture with acrylonitrile paraformaldehyde is substantially anhydrous there are produced certain new chemical com when using this source of formaldehyde in the pounds depending on the number of moles of reaction it is important to introduce, in addition, acrylonitrile which take part in the reaction. a sufficient amount of water to provide an aqueous When one mole of formaldehyde reacts, in ls reaction medium. aqueous reaction mixture with One mole of I have found that it is essential to bring the acrylonitrile there is produced the hemiformal reactants together in the presence of an alkaline of ethylene cyanohydrin, a compound having . catalyst, or condensing agent. Alkaline mate the following formula: rials, in general, are utilizable; however, with - HOCHOCH2CH2CN 20 those which are less alkaline than sodium car bonate as, for example, the alkyl amines, the re When one mole of formaldehyde, or polymer of action occurs more slowly. Alkaline condensing formaldehyde is reacted with two moles of agents, such as the alkali metal and alkaline acrylonitrile there is produced the formal of earth - metal oxides, hydroxides, carbonates, ethylene cyanohydrin, a compound having the 26 hydrides, alcoholates and cyanides will be found following structure: to give very satisfactory results. It is generally preferred to use the alkali metal hydroxides and NCCHCH2OCHOCH2CH2CN cyanides as, for example, sodium hydroxide and It is thus evident that in the aqueous reaction Sodium cyanide, since these are very satisfactory mixture the formaldehyde or paraformaldehyde 30 alkaline condensing agents. reacts with the vinyl cyanide in the form of the The alkaline catalyst should be present in hydrate of formaldehyde, i. e. as methylene amount Sufficient to render the reaction mixture glycol. distinctly alkaline. Ordinarily amounts rang Accordingly, one of the objects of this inven- . ing from 0.5% to 10% by weight based on the tion is to prepare novel and valuable chemical 85 total weight of the reaction mixture are suitable. compounds by reacting formaldehyde or form When the relatively stronger alkaline condensing aldehyde polymers with acrylonitrile in the agents such as sodium hydroxide are utilized, the molecular proportions of: one mole of formalde amount need not generally exceed 3%. hyde to One mole of acrylonitrile; and One mole In carrying out the reaction it is merely neces of formaldehyde to two moles of acrylonitrile. 40 sary to bring the formaldehyde or paraformal Another object of this invention is the prepara dehyde and acrylonitrile into contact in the tion of valuable chemical compounds, the hemi aqueous reaction mixture in the presence of the formal of ethylene cyanohydrin, and the formal alkaline condensing agent. Temperatures rang of ethylene cyanohydrin, by reacting acrylonitrile ing from 0 to i00° C. are suitable, the reaction with formaldehyde or a polymer thereof equivar dis being of course more rapid at the more elevated lent to formaldehyde in the reaction, said re temperatures. As the reaction is somewhat action being carried out in an aqueous reaction exothermic in character, when operating with medium containing at least one mole of Water large amounts of material it may be necessary per mole of available formaldehyde, and in the to provide cooling means to eliminate excess heat. presence of an alkaline condensing agent. These 50 In addition to the water in the reaction mix and still further objects of my invention will be ture there may also be present a diluent or an apparent from the ensuing disclosure of certain inert Solvent, although as a general rule the use preferred embodiments, thereof. of such diluents is not necessary or desirable, Both formaldehyde and paraformaldehyde Where a diluent is employed an inert solvent aay be utilized in the reaction as the source is such as hexane, benzene, ether or petroleum 2 2,852,671 ether is suitable. If desired, the formaldehyde The crude reaction mixture was then extracted or paraformaldhyde and acrylonitrile may be with ether and separated from the aqueous residue. brought together and the alkaline Catalyst dis On distillation of this extract 91 gms. of product solved in water added thereto. However, if de boiling at 140 C. to 155 C. at 4 mm. of mercury sired, the acrylonitrile, may be added directly to pressure was obtained. Fractional distillation of an aqueous solution of formaldehyde, such as the crude product gave a material boiling at the 37% commercial Solution, in which the 155 C. to 160° C. at 2 mm. of mercury pressure. alkaline condensing agent has been dissolved. The product is a clear yellowish liquid having an The particular order in which the reactants are odor similar to that of a fatty nitrile. On heat O ing with caustic soda solution it hydrolyzes with added is not important and any conventional evolution of ammonia. Molecular weight and procedure may be adopted. nitrogen analyses indicate that it is the formal The best yields of product are obtained when of ethylene cyano hydrin, CH2(OCH2CHCN). thereaction reaction is neutralizedmixture at withthe terminationacid before ofbeing the Various changes may be made in the above subjected to distillation or extraction with a suit 15 procedures given herein as illustrative of my able solvent in order to recover the hermiformal invention without departing from the scope or formal of ethylene cyanohydrin. The par thereof. ticular product resulting, i. e. the hemiformal I claim: . or formal product, is regulated by controlling 1. The process which comprises reacting a the ratio of the molar amount of formaldehyde 20 compound supplying-formaldehyde selected from (or formaldehyde polymer) to the molar amount the group which consists of formaldehyde and of acrylonitrile, in accordance with the above paraformaldehyde with acrylonitrile in an aque explanation. ous reaction medium containing at least one mole The new chemical compounds resulting, the of water for every mole of formaldehyde reacted, hemiformal of ethylene cyanohydrin and the 95 said reaction being effected in the presence of formal of ethylene cyanohydrin, are valuable as an alkaline condensing agent. intermediates for the preparation of plasticizing 2. The process which comprises reacting form agents and resinous products. aldehyde and acrylonitrile in an aqueous reaction The invention is illustrated by the following mixture containing at least one mole of water example: 30 per mole of formaldehyde reacted, said reaction Eacample being effected in the presence of an alkaline con densing agent. In a reaction flask equipped with stirrer, reflux 3. The process which comprises reacting para condenser and thermometer, there was intro formaldehyde with acrylonitrile in an aqueous duced 206 gms. (4 mols) of acrylonitrile and 64 reaction medium containing at least one mole gms. paraformaldehyde (equivalent to 2 mols of water per mole of formaldehyde reacted, said CH2O) mixed with 36 cc. water containing 2 gms. reaction being effected in the presence of an dissolved sodium hydroxide. This mixture- was then heated to reflux with continuous agitation alkaline condensing agent. and approximately 18 gms, of solid caustic soda 4. As a new chemical compound the formal of was added gradually over a period of 7 to 8 hours. 40 ethylene cyanohydrin. At the end of this period reaction was substan tially complete, chemical analysis indicating the JOSEPH FREDERC WAKER, presence of only a small quantity of free form aldehyde in the reaction mixture. .