2,729,676 United States Patent Office Patented Jan. 3, 1956 1. In order that those skilled in the art may better under stand how the present invention may be carried into 2,729,676 effect, the following methods are provided by way of illustration.To prepare g,6'-diselenodipropionic acid, an alkali PREPARATION OF fSELENODIPROPIONICCD s Selenide such as sodium, potassium, or ammonium selen Donald L. MacPeek, Charleston, W. Va., and William H. ide and the like is slowly reacted with beta propiono Rauscher, Brunswick, N. Y., assignors to the United lactone in aqueous solution to form the addition product. States of America as represented by the Secretary of The product is acidified with a suitable acid such as hydro the Army 0. chloric acid, etc. and the desired product is obtained by No Drawing. Application April 29, 1953, a suitable method such as extraction. The following Serial No. 352,053 examples are illustrative of preferred embodiments of the foregoing method. 1 Claim. (C. 260-537) EXAMPLE This invention relates to fungicidal compounds and 5 A quantity of 38 grams (0.25 mole) of sodium selenide more particularly to new compositions of matter having is dissolved as completely as possible in 50 ml. of water pronounced fungicidal activity. contained in a 500 ml. 3 necked flask having standard Electronic equipment in use may be exposed in many . taper joints. The flask is fitted with a dropping funnel instances to a combination of severe climatic conditions and motor stirrer. The mixture is stirred for about 10 Such as extremes of heat, cold, and humidity. The pres 20 minutes to aid solution and then is placed in a 15° C. ence of high humidity may have many deleterious effects bath. This bath temperature is maintained throughout upon the electrical insulation and consequently upon the the run. A quantity of 18 grams (0.25 mole) of beta surface characteristics of hook-up wire. propionolactone is added dropwise over a period of 30 It is known that currents may flow through the volume minutes with the evolution of much heat. After the com of the insulation and over its surface in various ways. 25 pletion of the addition, the mixture is then acidified by At high humidity, the current over the surface may be the dropwise addition of 50 ml. of concentrated hydro relatively large and may change markedly with change chloric acid. During the progress of the reaction, the in humidity. In electronic applications, such currents color of the solution changes to a deep red color and may flow from the bare conductor at a terminal back along considerable solid precipitates. The solution is allowed the surface of the wire insulation to some point where 30 to stand for a while to permit the HaSe formed in the the wire insulation may touch ground, an uninsulated reaction to escape. The reaction mixture is then placed component or another wire. Also, in the latter case, the in a continuous extractor and sufficient ether is added current may flow along the second wire to another ter to permit the extractor to function. After 6 hours of extraction, the ether possesses a definite yellow color and minal.Mold growth is associated with high humidities and 35 upon evaporation of the ether, a dry yellow residue hav moisture and moid growth both increase the dissipation ing a disagreeable odor remains. factor and capacitance measured along the surface of hook-up wire insulation. This increase is greatest at low EXAMPLE II frequencies and is apparently due to the polarization In this example, all quantities and conditions are kept effects of moisture absorbed at the surface. 40 the same as in Example I except for the temperature. Inasmuch as the deleterious factors of mold and high The addition of the lactone is started at 22 C. and a humidity are intimately related, surface electrical proper constant temperature is not maintained. The temper ties of hook-up wire can be greatly improved by the de ature will rise to about 85-95 C. by the end of the velopment of fungicidal compositions which remain stable addition and then fall back to room temperature. at high temperatures and which can be incorporated into hook-up wire so as to make it resistant to contamination EXAMPLE III In this example all quantities and conditions are kept byIt mold. is, therefore, a primary object of the present inven the same as in Example I other than that the temper tion to provide new compositions of matter having pro ature is maintained as near 0° C. as possible throughout nounced fungicidal activity and stability at high temper 50 theIt reaction.has been found from the above examples that the ature.It is a further object of the present invention to provide presence of small traces of atmospheric oxygen causes esters of 6,6'-diselenodipropionic acid having fungicidal decomposition of the metastable sodium selenide solu properties. tion to form plates of metallic selenium (gray form) upon It is another object to provide a method for preparing 55 the surface. They become heavy and sink leaving a fresh g,8-diselenodipropionic acid. liquid surface exposed where more decomposition and In accordance with the present invention there are loss can take place. To obviate this difficulty, it has been provided diesters of 6,6'-diselenodipropionic acid having found that flushing the apparatus in which the reaction the general formula takes place with nitrogen and also flushing the distilled 60 water from which the solution is made reduces the quan ROOC-CH2-CHg-Se-Se-CH2-CH-COOR tity of selenium which precipitates but does not com wherein R is an alkyl or an alkoxy alkyl radical. pletely eliminate the difficulty. Method of preparing Also, in accordance with the present invention, there (3,6'-diselenodipropionic acid taking these factors into is provided a method for preparing diselenodipropionic consideration are illustrated by the succeeding examples. acid comprising reacting beta propionolactone with sodium 65 selenide, acidifying the reaction product and allowing the EXAMPLE IV acidified reaction product to form the diselenodipropionic A 1 liter 3 necked flask with ground glass joints is fitted with a motor driven stirrer with a mercury seal, acidFor in athe better presence understanding of air. of the present invention, thermometer, and gas entrance and exit tubes. The gas together with other and further objects thereof, reference 70 exit tube is connected first to an empty 500 cc. suction is had to the following description and its scope will be flask which serves as a trap for any expelled reaction mix pointed out in the appended claim. 3 2,729,676 ture. The gases are passed from this flask to a second 4 suction flask which contains a dilute solution of sodium The above example essentially accounts for nearly all hydroxide or other suitable alkali to absorb any evolved the selenium. hydrogen selenide. A manometer is attached to the trap EXAMPLE VI flask to provide a visual means of observing the pressure A 3 necked 2 liter flask is fitted with a mercury sealed inside the system and a dropping funnel is attached to 5 motor driven stirrer, a thermometer, gas inlet and outlet an offset from the gas entrance tube. The apparatus is tubes and a dropping funnel. A flask fitted with a glass flushed with nitrogen for about 20 minutes at which point tube which extends below the level of the water in the about 0.25 mole (38 grams) of sodium selenide is dropped flask serves as a means of visually observing the relative in and covered with 250 ml. of distilled water which rate of the flow of nitrogen which is used to flush the has been flushed with nitrogen. The selenide is allowed 0 apparatus both before and during the reaction. After a to dissolve for about 30 minutes and the flask is then 20 minute period of flushing, 124.95 grams of sodium cooled to 10 C. by suspension in an ice bath. This selenide is placed in the flask and immediately there temperature is maintained as the upper limit for the rest after, 1 liter of distilled water is added through the drop of the reaction period. A weight of 19.5 grams of the ping funnel. The mixture is stirred for 30 minutes to beta propionolactone is added slowly through the drop 5 allow the sodium selenide to go into solution. During ping funnel at the rate of approximately 10 ml. per hour. this entire period, the flask is suspended in a salt-ice bath, The mixture is stirred for about 1 to 2 hours after the the stirring also aiding to bring the solution to reaction lactone is completely added. It is to be noted that with temperature of about 0° C. The data in the following this procedure, no voluminous and amorphous precipi table applies to the temperature control, nitrogen pres tate forms at any time during the reaction. The mix 20 sure and rate of addition of the beta propionolactone to ture is then acidified by the dropwise addition of an the sodium selenide solution. excess of concentrated hydrochloric acid with no large volume of hydrogen selenide being given off and the pre Ml. Lactone cipitate which settles out in this reaction is light yellow, M. of Pressure Added 25 Lactone Nitro not the dark mass obtained by the procedures illustrated gen, in Examples I, II, and III. Thus, the increased fluidity Added p. S. i. per 15 of the entire reaction mixture makes handling much Min. Min. easier and the extraction which follows is much more ----- rapid with more complete removal of the organic prod 18.