US2272577A - Composition and method for bleaching milling products - Google Patents

Description

Patented Feb. 10, 1942' COMPOSITION AND LIETHOD FOR BLEACH- ING MILLING PRODUCTS Frederic 11. Penn, Dallas, Tex.

No Drawing. Application June 11; 1941, Serial No. 397,622

15 Claims.

My invention relates to the treatment of'wheat flour and other milling products, and more particularly has reference to the bleaching of flour and the like by means of non-flammable or ganic peroxide compositions, which increase the ash content of the flour only a negligible amount.

Organic peroxides, notably benzoyl peroxide, derived from hydrogen peroxide, have long been used as bleaching agents for flour. They are quite flammable, and decompose in the presence of spark, flame, or temperatures above 105 0., and'are even explosive under certain conditions. Therefore, considerable caution has been necessary in the handling of these organic peroxides.

To prepare organic peroxides for bleaching flour, it is necessary that the organic peroxide be in dry finely divided form in order to be intimately mixed with the flour. To accomplish fine grinding, the organic peroxide is ordinarily mixed with an inert material, such as dicalcium phosphate or the like, and then ground to the desired fineness. Although these inert materials prevent the decomposition of the organic peroxides during the grinding process, they have no efiect on the flammability of the organic peroxide.

When water soluble alkali metal phosphates, borates and sulphates containing, per mole, about two to about ten moles of water of crystallization are used as a carrier and for grinding the organic peroxides, the flammability of the organic peroxides, when used in th amount of about twenty per cent., can be prevented. The organic peroxide bleaching compositions containing alkali metal salts, having per'mole about two to about ten moles of water of crystallization, are subject to packing and lumping, and as such are not satisfactory for use, and for this reason, it is necessary to include a packing and lumping inhibitor with the organic peroxide, alkali metal salt compositions.

This application is a continuation in part of my co-pending applications, No. 387,781 and No. 387,782.

An object of this invention is to provide nonfiammable organic peroxide compositions in dry powdered non-packing and non-lumping form.

wheat, etc. The patent flour is the best grade, having an ash content of not more than .400%. Flour having an ash content of more than .400% is classified as clear and is sold at lower prices than patent flour.

Potassium or sodium phosphate, when used as a carrier and containing water of crystallization,

'in combination with organic peroxides, do not increase the ash content of the flour to the extent as does calcium sulfate or calcium phosphate or other calcium compounds. Water sol-- uble alkali metal salts are capable of carrying more moles of water of crystallization than the water insoluble alkaline earth metal salts. For instance, the increase of the ash in the flour due to the added benzoyl peroxide bleaching agent is almost twice as much when calcium sulfate, which contains a maximum of only two moles of water of crystallization, than when sodium phosphate containing ten moles of 'water of crystallization is used as a carrier.

Liquid peroxides, as acetyl peroxides, or inactive peroxides, as phthalyl peroxide, are not suitable for the purpose of this invention. The peroxides intended for use in the present invention are the so-called active organic peroxides, these being primarily the peroxides of the kind that release nascent oxygen. The active organic peroxides of the type mentioned are the ones which are particularly objectionable because of flammability.

In my prior patent, No. 2,208,471, July 16, 1940, I have shown that the flammability of the active organic peroxides can be prevented by means of certain aluminum sulfates containing about twenty-four moles oi. water of crystallization. I have now found that this result can also be accomplished by combining with the active organic peroxides water soluble alkali metal salts containing, per mole, about two to about ten moles of water of crystallization.

Accordingly, the dry powdered bleaching composition of the present invention comprises, in addition to the active organic peroxide, a sufflcient quantity of an alkali metal salt of the character above mentioned to prevent the flammability of the peroxide. Among these salts are sodium or potassium phosphate, sodium sulfate, potassium and sodium borate, containing from about two to about ten moles of water of crystallization, the latter characteristic being the one which renders the compounds efl'ective in preventing flammability of the active organic peroxides. In this respect, the salts used in the present invention differ in form from the calcium sulfate, calcium phosphate and magnesium carbonates heretofore employed with organic peroxides. The preferred water soluble alkali metal salt of this invention for preventing flammability is sodium pyi'o phosphate containing about ten moles of water of crystallization.

The alkali metal salts of the present invention, due to their water content, are more or less damp, and hence not susceptible'to fine grinding, and for this reason, a packing inhibitor, such as anhydrous magnesium carbonate, in finely divided form, should preferably be used to facilitate fine grinding and to prevent packing of the bleaching composition. In place of anhydrous magnesium carbonate, other packing anhydrous inhibitors, such as anhydrous tricalcium phosphate, aluminum oxide or aluminum silicate, may be used.

Benzoyl peroxide is' the preferred peroxide used as the active organic peroxide, but other active peroxides, as cinnamoyl and phenyl acetyl peroxide may also be used as the bleaching com ponent of the composition.

Illustrative'of the preparation of the preferred non-flammable organic peroxide composition,

twenty grams of dry benzoyl peroxide, 65 grams of sodium pyrophosphate containing about ten moles of water of crystallization, and 15 grams of anhydrous magnesium carbonate, are mixed together and ground to a finely divided powder. The resultant product is non-flammable, nonexplosive, and is ready for use as a flour bleaching agent.

In place of sodium pyrophosphate of the example given above, sodium borate or sodium sulfate containing about two to about ten moles of water of crystallization may be used.

peroxide, and an anhydrous packing inhibitor.

3. A flour bleaching composition comprising a dry free flowing powdered mixture of an active organic peroxide having substantial flour bleaching properties, a water soluble alkali metal phosphate containing, per mole, about two to about ten moles of water of crystallization, in sumcient amount to prevent flammability of the organic peroxide, and anhydrous magnesium carbonate.

4. A flour bleaching composition comprising a dry free flowing powdered mixture of benzoyl peroxide, a water soluble alkali metal phosphate containing, per mole, about two to about ten moles of water of crystallization, in sui'flcient amount to prevent flammability of the benzoyl peroxide, and an anhydrous packing inhibitor.

5. A flour bleaching composition comprising a dry free flowing powdered mixture of benzoyl In practicing the flour bleaching method ofthis invention, the non-flammable benzoyl peroxide, water-containing sodium pyrophosphate, anhydrous magnesium carbonate composition, produced as above described, is fed directly into the flour stream at any convenient point during the milling operation, and intimately mixed with the flour by means of powder feeding machines now in general use in the mills, in the proportion of about A; ounce to one barrel (196 pounds) of flour. For a thorough distribution of such small amounts of the bleaching composition in the flour, the composition should be in the form of a dry free flowing finely divided powder. A satisfactory bleaching is obtained by exposing the flour to the action of the bleaching composition for about twenty-four hours.

In the appended claims, I have characterized the peroxides as active and having substantial flour bleaching properties, in order to distinguish them from those organic peroxides which are of insufficient activity and bleaching power to effect bleaching of the flour.

Having described my invention, I claim:

1. A flour bleaching composition comprising a dry free flowing powdered mixture of an active organic peroxide having substantial flour bleaching properties, a water soluble alkali metal salt containing, per mole, about two to about ten moles of water of crystallization, in sufficient amount to prevent flammability of the organic peroxide, and an anhydrous packing inhibitor.

2. A flour bleaching composition comprising a dry free flowing powdered mixture of an active organic peroxide having substantial flour bleach ing properties, a water soluble alkali metal phosphate containing, per mole, about two to about ten moles of water of crystallization, in sufficient amount to prevent flammability of the organic peroxide, a water soluble alkali metal borate, containing, per mole, about flve to about ten moles of water of crystallization, in suflicient amount to prevent flammability of the benzoyl peroxide, and anhydrous magnesium carbonate.

6. A flour bleaching composition comprising a dry'iree flowing powdered mixture of benzoyl peroxide, sodium borate containing, per mole, about ten moles of water of crystallization, in suflicient amount to prevent flammability of the benzoyl peroxide, and anhydrous magnesium carbonate.

7. A flour bleaching composition comprising a dry free flowing powdered mixture of benzoyl peroxide, sodium pyrophosphate containing, per mole, about ten moles of water of crystallization, in sufficient amount to prevent flammability oi' the benzoyl peroxide, and anhydrous magnesium carbonate.

8. A flour bleaching composition comprising a dry free flowing powdered mixture of benzoyl peroxide, sodium sulfate containing, per mole, about ten moles of water of crystallization, in sufiicient amount to prevent the flammability of the benzoyl peroxide, and an anhydrous magnesium carbonate.

9. A method for bleaching wheat flour and other milling products, which comprises mixing with the dry milling product a dry free flowing powdered mixture of an active organic peroxide having substantial bleaching properties, an anhydrous packing inhibitor, and a water soluble alkali metal salt containing, per mole, about two to about ten moles of water of crystallation, the peroxide being in sumcient amount to bleach the milling product and said water soluble alkali metal salt being in suiflcient amount toprevent the flammability of the peroxide, and subjecting the dry milling product to the action of said mixture for a sufficient time to bleach the produc 10. A method for bleaching wheat flour and other milling products which comprises mixing with the dry milling product a dry free flowing powdered mixture of an active organic peroxide having substantial bleaching properties, an anhydrous packing inhibitor, and alwater soluble alkali metal phosphate, containing, per mole, about two to about ten moles of water of crystallization, the peroxide bein in suflicient amount to bleach the milling product and said phosphate being in sumcient amo t to prevent flammability of the peroxid and subjecting the dry milling product to the action of said mixture for a suflicient time to bleach the product.

11. A method for bleaching what flour and other milling prciucts which comprises mixing bleach the milling product and said borate being with the dry milling product a dry free flowing powdered mixture of benzoyl peroxide, anhydrous magnesium carbonate, and a water soluble alkali metal salt containing, per mole, about two to about ten moles of water of crystallization, the peroxide being'in sufficient amount to bleach the milling product and said salt being in suflicient amount to prevent flammability of the peroxide, and subjecting the dry milling produce to the action of said mixture for a sufficient time to bleach the product.

12. A method for bleaching wheat flour and other milling products which comprises mixing with the dry milling product a dry free flowing powdered mixture of benzoyl peroxide, an anhydrous packing inhibitor, and a water soluble alkali metal borate containing, per mole, about flve to about ten moles of water of crystallization, the peroxide being in sufllcient amount to in suflicient amount to prevent flammability of the peroxide, and subjecting the dry milling product to the action of said mixture for a sufilcient time to bleach the product.

13. A method for bleaching wheat flour and other milling products which comprises mixing with the dry milling product a dry free flowing powdered mixture of benzoyl peroxide, anhydrous magnesium carbonate and sodium borate containing per mole, about ten moles of water of crystallization, the benzoyl peroxide being in I suflicient amount to bleach the milling product and said borate being in suflicient amount to prevent flammability of the-peroxide, and subjecting the dry milling productto the action of said mixture for a sufllcient time to bleach the milling product.

14. A method for bleaching wheat flour and other milling products which comprises mixing with the milling product a dry free flowing powdered mixture of benzoyl peroxide, anhydrous magnesium carbonate and sodium pyrophosphate containing, per mole, about tenmoles of water of crystallization, the benzoyl peroxide being in sufficient amount to bleach the milling product, and the sodium pyropl'b'sphate being in suflicient amount to prevent flammability of the benzoyl peroxide, and subjecting the dry milling product to the action of said mixture for a sufilcient time to bleach the milling product.

15. A method for bleaching wheat flour and other milling products which comprises mixing with the milling product a dry free flowing powdered mixture of benzoyl peroxide, anhydrous magnesium carbonate and sodium sulfate, containing per mole about ten moles of water of crystallization, the benzoyl peroxide being in suflicient amount to bleach the milling product and the sodium sulfate being in suflicient amount to prevent flammability of the benzoyl peroxide, and subjecting the dry milling product to the action of; said mixture for a sufficient time to .bleach the milling product.

FREDERIC H. PENN.