US2112242A - Process for activating provitamins - Google Patents

Description

B. KRAMER ET AL.

PROCESS FOR ACTIVATING PROVITAMINS Filed March 19, 1936 VARIABLE 9-1 VOLTAGE sou RCE CURRENT CYCLES PER SECONU INVENTCRS BENJAMIN KEAMEE SAMUEL NATEZLSO/V ALEEWA'SOEKL m g .1 ATTORNEY Patented Mar. 29, 1938 g UNITED STATES PATENT OFFICE I PROCESS Fort ACTIVATING PiiovITAMINs Benjamin Kramer, Samuel Natelson, and'Albei-t E Sobel, Brooklyn, N. Y. I

- Application March 19, 1936, Serial No. 69,736

9Ciaims. (01104-31) This invention relates to antirachitic vitamins antirachitic vitamin yield will be materially diand, more particularly, relates to novel apparatus 'minished. On the other hand, improper applicafor and methods of converting provitamins into tion of too high a potential for that frequency antirachitic vitamins. etc. may result. in a. spark discharge .which will Heretofore, several methods have been proposed destroy the provita'mins. Application of freand used to antirachitically. activate foods and quencies below or above the critical range also sterols having no antirachitic potency. The most reduces the efiiciency of antirachitic conversion of Y widely accepted process for antirachitically' actithe provitamins. w vating substances comprises exposure to a source We have found that the most economical pro- 10 of ultra-violetJlight. Commercial production by duction of substances containing antirachitic vita- 10 such a process requires an expensive investment mins is to activate ergosterol or crude cholesterol in materials, particularly quartz. A quartz and subsequently introduce a small percentage of mercury arc lamp is used to generate ultra-violet the activated sterols to foods and medicines, for rays which are directed upon the substance in a example yeast, olive oil, milk, cod liver oil and the I solid state or, more generally, in a suitable liquid like. The ergosterol or crude cholesterol is ap- 15 solution contained in quartz flasks or the like. p ied b twee t electrodes of e appa a us ac- Production of ultra-violet light by sources other cording to our present invention, preferably ina than a mercury arc lamp, such as the glow dissolid,loosely powdered state. Inanother form of charge, open arc discharges or thecorona disour invention, the sterols or provitamin is dison charge are relatively inefficient. Exposure of prosolved in a suitablesolvent as, for example, ether 00 vitamins to open are or corona discharges results and introduced between the discharge electrodes in the destruction of the vitamin almost as rapidly in a fine spray; a i as it is formed.v The other proposed" methods for We have found that the process according to antirachitically activating :provitamins are of our presentinvention also has a sterilizing effect mere laboratory. significance on account of the uponthefoodsor Subs ances subjected to it in that i very low efiicienoies of conversion together with bacteria, PrOtO Oa' other micro-Organisms are the expensive apparatus and the skilled manipudestroyed. Foods which possess antirachitic lation required. These methods include: cxp pe s in a greater 0 less r such as milk, posure of the material .to Xrays; bombardment olive oil, yeast, cod liver oil and the like, may be of the material by electrons in a cathode ray directly activated by the brushdischarge ap- 30 tube subjection of the material to a high frep r t s of our present invention.

quency alternating current greater than a Accordingly, an object of our invention is to thousand cycles. provide novel methods of converting provitamins We have discovered a simple, inexpensive and into antiratchitic vitamins. 3;; very efficient method of'antiratchitically activat- Another object of our invention is to convert 3 ing provitamins y an electric dischargey a provitamins into antirachitic vitamins by a brush extended investigation of the action of the-difdischarge, ferent types of electrical discharges through gases further object of our invention is to provide uponprovitamins, We have" discovered that y simple, inexpensive and efficient apparatus for 4o care y Controlling the r ou p m a and methods of converting provitamins such as 0 critical condition exists whereby the conversion of sterols i t antirachitjc vitamins provitamins to antiratchitic vitaminsis extremely still a furthe Object of our invention is to fav ra le. The Critical electriflal discharge, e vide novel apparatus for andmethods of sterilizerally referred to as the brush discharge, performs m f d Substances the efficient antiratchitic conversion. We have These and other objects of Our'invention Wm 45 found that r a partlcular physlcal apparatus a be evident in the following description in connec most favorable voltageexists, dependent upon the on with the drawin in which spacing of the electrodes between which the material is placed and thata most suitable frequency 3? 1 is Sc emanc dlagram usedtm the so of application of the alternating current exists of descnptlon of mdischarge phenomena the order of 250-350 cycles. As will be explained t gases in more detail hereinafter, a voltage below the Figure 2 is a qualitative graphical representacritical for a particular frequency, area and spaction of the e l gaseous electric a ge ing of the plates and dielectric will produce a glow phenomena.

r, discharge instead of a brush discharge and the Figure 3 is a modification of Figure'l.

Figure 4 is a partial perspective illustration of a preferred embodiment of our present invention.

Figure 5 is a qualitiative curve representing the efliciency of conversion of provitamins to antirachitic vitamins withwrespect to the frequency of the applied alternating current potential.

When a voltage is applied between two spaced conductors having a gaseous atmosphere between, a number of distinct types of electrical discharges may take place between the plates through the gas dependent upon the nature and magnitude of the potential applied to these plates. A variety of phenomena accompanies gaseous electrical discharges including luminous, thermal, magnetic, mechanical and chemical effects in varying degrees. In accordance with our present invention, the chemical action of the electrical discharge is utilized and the conditions of operation are adjusted so as to produce the type of discharge having a maximum chemical action and a minimum of the other physical actions. This type of electrical discharge is known as the brush discharge.

In order to clearly set forth the critical parameters for optimum antirachitic conversion of the materials, the following discussion as to the several types of electrical discharge is presented.

Referring to Figure 1, two metallic plates l0 and II are spaced from each other by a flxed amount, for example, one centimeter. The space I! between electrodes lil and II contains a gaseous atmosphere for example ordinary air at atmospheric pressure. A variable high potential or voltage source I3 is connected to plates l0 and Ii by corresponding conductors I4 and it.

An ammeter 5 may be inserted in series with conductor ii for observation of the current flowing during an electrical discharge between plates in and ii.

Figure 2 is a graph representing the variation in with a fixed spacing. At low voltages, for example below one thousand volts, practically no current will flow between the electrodes. As the voltage between the plates i0 and II is slowly increased, minute current will ilow between them as represented by curve ii. The discharge I1 is characteristically non-luminous or invisible and is accompanied by negligible chemical or other physical efiects. At a certain region I! which is definite for given conditions of temperature, pressure and electrode spacing the glow discharge begins which represents a discontinuity in the graph. Curve l9 represents the voltage-current relation of the glow discharge. The voltage may be increased to a very high value and the glow discharge will still be maintained and the current will correspondingly increase. The glow discharge is accompanied by a characteristic luminosity which includes ultra-violet light.

As the voltage is further increased, it will reach a peak value which is practically the maximum voltage which the electrodes i0--Il can support for a particular gaseous atmosphere and spacing. The glow discharge disappears at the 'region 20 and the characteristic brush discharge occurs. The brush discharge has sometimes also been called the silent discharge or the dark discharge. These terms are misnomers since the brush discharge is neither silent nor dark for it is attended by a peculiar sound and by some light.

By the term brush discharge as used hereinafter in the specification and claims, we refer to the electrical discharge produced across a region by a voltage gradient which corresponds to substantially the maximum voltage which can be supported between the electrodes bounding the region, other conditions remaining the same. We further distinguish the brush discharge as the electrical discharge occurring after the glow discharge, on increasing the voltage, and corresponds to the region characterized by the curve portion 20 of Figure 2. The brush discharge corresponds in Figure 2 to the discharge produced in the vicinity of the peak voltage ea. Other conditions which aifect the particular brush discharge voltage for carrying out our process are the frequency of the applied voltage, the spacing of the bounding electrodes, the character of dielectric material used and the gaseous condition within the discharge region.

The brush discharge is maintained by careful adjustment of the voltage for a given structure. Increasing the electrical energy or current supply to the electrodes causes the production of the spark discharge represented by region 1|. Region 22 represents the electric flame which results from further increasing the current supply. Curve 23 represents the negative voltage-current characteristic of the high tension arc and region 24 represents the low tension are as is well known by those skilled in the art. It is to be understood that the graph plotted in Figure 2 is merely a qualitative representation of the several types of electrical discharge phenomena and that the actual voltage and current depend upon the type,

surface area and shape of the oppositely disposed electrodes, the spacing between said electrodes, the type of gas and its temperature and pressure as contained between the electrodes. The type of voltage which produces the electrical discharge characteristics represented in Figure 2 may be an interrupted direct current or an alternating current voltage. The frequency of the interruptions or alternations of the voltage source should be relatively low, for example, below a thousand cycles, otherwise diiferent electrical actions will occur. Asthe frequency of the voltage source is increased, the peak voltage supported, corresponding to so of Figure 2, will be lowered. An increase in frequency will increase the current flow between the electrodes Ill-II due to a capacitative or reactive current flow due to the function of the plates |I| ll as an electrical condenser.

The phenomena of the electrical discharge becomes more complicated than the relatively simple representation of Figure 2 when dielectric material is interposed between the electrodes ill-4 I.

Referring to Figure 3, a glass plate 25 is placed adjacent to the inner surface of electrode ill and another glass plate 26 at the inner surface of plate ii. A variable high potential alternating current source 21 is applied to the conductors i4--II. If the generator 21 is operated at two hundred cycles and the voltage applied to the electrodes Ill and II is increased until the brush discharge corresponding to curve 20 in Figure 2 occurs, it will be found that the brush discharge will occur when the electrodes l0 and I l arecloser together than the corresponding case where no dielectric plates 25-26 are used. If the plates l0 and i l of Figure 3 are separated a distance equal to that described in connection with Figure 1, namely one centimeter, then the maximum voltage corresponding to an of Figure'2 will be greater at the brush discharge. The higher voltage is due to the presence of the dielectric material, namely the glass plates 2526 interposed beevident that a brush discharge may be produced between two electrodes as long as ,a gaseous atmosphere exists between them, and that it is difficult to express the value of the voltage to be applied for all conditions. If the frequency of generator 21 is increased, the maximum voltage which a given discharge structure can support will be lessened.

The critical spacing of the electrodes maybe determined foraparticular voltage and frequency supply as follows: The electrodes l0 and II, with s the dielectric materials 25 and 26 in place (Fig. 3)

if required, are connected to the supply and are gradually brought together until the easily recognizable spark discharge begins. The electrodes are then slowly moved apart until the spark discharge just disappears. The brush discharge will then be evident to those. skilled in the art. 7

We have discovered that provitamins placed in the electrostatic field within a brush discharge are efficiently converted into antirachitic vitamins. We have also found that the antirachitic conversion is relatively insignificant for electrical discharges occurring at the lower voltages, namely the non-luminous discharge represented by curve I! .in Figure 2 and the glow discharge represented by curve l9; and that the discharges occurring beyond the brush discharge,v namely the spark discharge and the electric are discharges represented by curves 2|, 22, 23 and 24 of Figure 2 actually destroy the provitamins. It

is to be, understood thatthe brush discharge represents an electrochemical conversion of theprovitamin to the antirachitic vitamin. This electrochemical action is analogous to the production of ozone-which has also been found to be most efficient in the brush discharge region.

In a preferred embodiment for carrying out the process of our present invention, we utilize two concentric glass tubes provided with metal foil: electrodes as illustrated in Figured. An outer cylindrical glass tube 28 is provided with a metallic plate or foil electrode 29 attached to its outer surface. The inner concentric glass tube 30 is coated with a metallic sheet or foil electrode 30 upon its inner surface. The annular-distance between concentric tubes 28 and 30 is optional and determines the volume capacity of the appait should be in a loosely powdered form. The value of the voltage from electric source 32 applied between electrodes 29 and 3| is predetermined so as to produce a brush discharge therebetween. One must be careful that the. voltage applied to the apparatus produces the true brush discharge corresponding to curve 20 of Figure 2. If the current is too low, the inefficient glow discharge represented by curve 19 will take place; if the current is too high, a. spark discharge represented by curve 2| will take placeand destroy any vitamins that might-be formed. In a par ticular example, glass cylinders 28 and 30 of one millimeter thickness and with an annular space of two millimeters required a voltage of the order of 8000 volts to produce a brush discharge.

We have found that it is necessary to place the provitamin substance 35 in the electrostatic field I within the actual brush discharge for antiarchit- I icl conversion. Experiments'have shown that if theprovitamin substance 35 be placed at the outer regions of the annular space, namely the regions 36 and 3'! immediately outside of the direct electrostatic field; negligible antirachitic vitamin conversion] results, demonstrating absence of ultra violet light conversion.

. An important feature of our present invention resides in the use .of a critical frequency for the most eflicient antirachitic conversion of the provitamin substance; We" have -discovered that for most provitamin substances, particularly the sterols, the optimum frequency range of conversion occurs between 250 and, 350 cycles. The efficiency of"conversion" decreases with frequencies below 250 cycles, as well as for frequencies above 350 cycles. Figure 5 is a qualitative curve representation' 38 of the relative conversion of provitamin substances" to antirachitic vitamins plotted withv respectfto the frequency of the applied poteritialin cycles per second.

It is to be understood that a brush discharge occurs along the'points of curve 38 for the various frequencies plotted. At zero frequency a relatively've y small yield occurs As the frequency is increased to 250 cycles, the yield correspondingly increases until the maximum. As the frequency is further increased to about 350 cycles, the efficiency of con version continues near the maximum. For particular substances, a peaked nature of curve 38; will be evident" at a single critical frequency in the order of 250-350 cycles.

However, inFigure ,5,we have not" attempted to accurately represent any particular case but rather tov give an approximate conception of the effect and range of thefrequency of the voltage ciency of conversion diminishes until at 1000' cycles and above, the efficiency is relatively small.

As seen by curve 38 of Figure 5 "approximately 50% ofthe maximum efficiency or yield occurs with frequencies in the range'of 150 to 550 cycles per second. By choosing the intermediate fre quency range of'250 to 350 cycles per second the maximum efficiency or yield is approached. ,For most provitamin substances a frequency of about 300 cyclesper secon'd'will produce best results.

It is necessary for a gaseous atmosphere to prevail between ,thedischa'rge electrodes, therefore the solidprovitam'in 35 should be in a loosely powdered state. When air is used, ozoneis formed during the activation process according to our invention. Ozone 'orjtheaction of the oxygen itself acts 'toslowly decompose the vitamins and accordingly somewhat reduce the yield.

We have found that if the'activation process between the concentric tubes 28 and 30 is carried on in the presence of an inert gas such as nitro-,

gen thev efficiencyof conversion is materially increased. Nitrogen may either be' continuously .passed'through the substance "35 being activated in the annular chamber or may be confined to the annular chamber if it is made gas tight as will be understood by thoseskilled' in the art.

1N0 activation is'obse'r'ved if a solution of provitamin' fills the annular space, since a brush discharge cannot be established 'thru the solvent.

A modification for activating the ergosterol 01' other provitamin resides incontinuously spraying it in the formof a fine d'us't between the annular spaceofa relatively long structure. The

Till

ergosterol, crude cholesterol or other provitamin substance may be dissolved in a suitable solvent such as ether or alcoholand passed through the brush discharge in the annular space in the form of a fine spray." Antirachitic conversion of provitamins to vitamins is evident with an exposure as low as two minutes. Increasing the time of exposure to a predetermined maximum of thetype and form of provitamin substance being.

activated.

Another important factor for increasing the efliciency of conversion'is the temperature at which the conversion takes place. It is preferable to carry out the process at a temperature of about C. although good results will be obtained at ordinary room temperatures. The temperature of the whole apparatus, and therefore of the substance 35 being converted, may be maintainedcool by means of a fan directly blowing thereon or preferably by the continuous circulation of cooling water through the central circular tube 30 of the apparatus. Other suitable forms of cooling will also be evident to thoseskilled in the art.

The true nature of the electro-chemical action during the brush discharge has been in controversy for some time in the art. However, in the present case, the activation appears to be due to the impingement of ions or activated atoms or moleculesproduced within the brush discharge from the gaseous dielectric, upon the provitamin substance which release their energy to the provitamin, converting it to the antirachitic vitamin.

The important factors for the production of antirachitic vitamins from provitamins are the production of a brush discharge; placing a provitamin substance such as ergosterol or crude cholesterol within the brush discharge preferably insulated from the metallic electrodes by glass plates or the like; using a loosely powdered provitamin substance structure, or in the form of fine dust spray, or a spray of a solution of provitamin substance through the brush discharge; preferably maintaining an inert gaseous atmosphere such as nitrogen and keeping the substance coolpreferably at 0 C. The production of'the brush discharge should be determined for each particular structure designed. The necessary voltage is determined'by the shape of the electrodes, their size and their spacing. Thefrequency of the applied voltage should preferably be in a most efficient range for conversion. generally within 250 and 350 cycles. A suitable source of the high voltage alternating current necessary for carrying out our process will be evident to those skilled in the art. An alternating current generator connected to a step-up transformer will provide the necessary high voltage. optimum frequency. For small quantity production, an induction coil adjusted to, for example, 250 cycles of interruption, may be used to maintain the brush discharge in an apparatus constructed to operate with the voltages, for example 8000 volts, presented at the output thereof.

A convenient way of producing the desired frequency and voltages is to generate the frequency by one of the usual types of variable audio oscillators, to amplify this by means of the standard types of pie-amplifiers and amplifiers and to The alternator is adjusted to the proper feed this into a transformer designed to raise the voltage to the desired range. A condenser board is used in connection with the final transformer so as to keep the current and voltage in phase.

The ergosterol or crude cholesterol is a concentrated antirachitic vitamin source, It is too potent for direct consumption. Small amounts are administered or eaten, preferably in combination with a. food or medicine. A small percentage of the activated material is mixed with cod liver oilyyeast, milk or other edible substance. No change in taste or odor of the food occurs. The antirachiticpotency of the edible material treated in this manner is equivalent to direct activation thereof. It is much more economical to produce edible or medicinal antirachitic sub stances by adding a small percentage of concen trated antirachitic vitamin content material to the substances, as compared to direct activation thereof. It is to be understood that antirachitically potent substances may be directly activated inaccordance with our present invention.

This application is a continuation in part of our application Serial No. 723,314, filed May 1, 1934.

We claim:

1. The process for antirachitically activating provitamins which comprises introducing provitamin material into a gaseous region and applying a voltage gradient across the gaseous region containing the provitamin material for producing a gaseous brush discharge about the provitamin material, whereby the provitamins are converted into antirachitic vitamins by the brush discharge acting on the provitamin material in the gaseous provitamins which comprises introducing provitamin material in a powdered and loosely packed form into a gaseous region and applying a voltage gradient across the gaseous region containing the provitamin powder at substantially the maximum voltage which the region can support for producing a gaseous brush discharge about the provitamin material, whereby the provitamins are converted into antirachitic vitamins by the brush discharge acting on the provitamin material in the gaseous atmosphere.

4. The process for antirachitically activating provitamins which comprises continuously passing a solution of provitamin material as a fine spray through a gaseous region and applying a voltage gradient across the gaseous region containing the provitamin spray at substantially the maximum voltage which the region can support for producing a gaseous brush discharge about the provitamin material, whereby the provitamins are converted into antirachitic vitamins by the brush discharge acting on the provitamin material.

5. The process for antirachitically activating provitamins which comprises introducing provitamin material into an inert gaseous'region'and applying a voltage gradient across the gaseous region containing the provitamin material at substantially the maximum voltage which the region can support for producing a gaseous brush discharge about the provitamin material, whereby .the provitamins are converted into antirachitic vitamins by the brush discharge acting on the provitamin material in the inert gaseous atmosphere.

6. The process for antirachitically activating provitamins which comprises introducing provitamin particles into a region of nitrogen gas and applying a voltage gradient across the gaseous region containing the provitamin particles at substantially the maximum voltage which the region can support for producing a gaseous brush discharge about the individual provitamin particles, whereby the provitamins are con erted into antirachitic vitamins by the brush discharge acting on the provitamin particles in the hi ogen atmos-\ phere.

'7. The process of antirachitically activating provitamins which comprises introduci g provitamin material into a gaseous region and applyihg a voltage gradient across the gaseous region containing the provitamin material for producing a gaseous brush discharge about the provitamln converted into antirachitic vitamins by the interrupted brush discharge acting on the provitamin material in the gaseous atmosphere.

8. The process of antirachitically activating provitamins which comprises introducing provitamin material into a gaseous region and applying a voltage gradient across the gaseous region containing the provitamin material at substantially the maximum voltage which the region can support for producing a gaseous brush discharge about the provitamin material, and generating the brush discharge with an alternating voltage having a frequency of. about 300 cycles per second, whereby the provitamins are converted into antirachitic vitamins by the brush discharge acting on the provitamin material in the gaseous atmosphere.

9. The process for antirachitically activating provitamins which comprises introducing provitamin particles into a gaseous region and applying a voltage gradient across the gaseous region containing the provitamin particles at substantially the maximum voltage which the region can support for producing a gaseous brush discharge about the individual provitamin particles, and generating the brush discharge with an alternating voltage having a frequency in the range of to 550 cycles per second, whereby the provitamins are converted into antirachitic vitamins by the alternating brush discharge acting on the provltamin particles in the gaseous atmosphere,

BENJAMIN KRAMER. SAMUEL NATELSON. ALBERT E. SOBEL.

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