US2384238A - Stabilized furfural - Google Patents

Description

Patented Sept. 4, 1945 STABILIZED FURFURAL Rock L. Comstock, -Weeks, La., assignor to Bay Chemical Company, Inc., New Orleans, La., a

corporation oi Louisiana No Drawing. Application August 9, 1943,

Serial No. 498,000

6 Claims.

This invention relates to the stabilization of future].

Furfural is an organic liquid which is normally clear or colorless. It has many uses in modern technology, among which are its employment as a solvent or distributing agent and also as a base for certain synthetic resins. Furfural readily condenses with various reagents into larger molecular aggregates to form resinous plastics. However, furfural is normally unstable so that its tendency to resinify'persists to an undesirable degree in the absence of the employment of stabilizing agents. Furfural becomes altered spontaneously even in storage, to produce gummy derivatives. These derivatives are dark in color and darken the furfural in which they are formed,

even when present in considerable dilution. The dark color of furfural is. therefore, evidence of deterioration of the furfural.

It has heretofore been diflicult to prevent this chemical alteration of furfural to form dark gummy products because the nature of this change is not known with certainty. It has been supposed to be due to oxidation. It is known that furfural is an organic compound of a heterocyclic system, and that its structure is that of an aromatic-like, five membered ring containing an oxygen atom in the ring, in which the carbon atoms attached to the oxygen are attached to -other carbon atoms by double bond, so that furiural in structure is an unsaturated ring. The accepted chemical structure of furfural is:

invention indicate that the darkening of furfural during storage is not primarily an oxidation phenomenon, but is the result of polymerization, and

- that effective means of control is not primarily'a matter of avoiding oxidation, but of inhibiting polymerization.

An object of this invention is to stabilize furi'ural against alteration during storage. A further purpose is to maintain the clarity or colorless nature of furfural even in the presence of air.

A particular object is to prevent spontaneous formation of dark gummy derivatives in furfural inhibit undesirable chemical deterioration of fur-' fural, but a range of from 0.01% to 0.1% is preferred.

The following examples are presented, as the result of tests, as showing the efficacy of butyramid as a stabilizer of furfural compared with certain other compounds:

Test No. Furfural Prospective stabilizer These preparations were prepared in glass test tubes, stoppered, exposed to ultraviolet light, and frequently observed thereafter. At the time of preparation, Test No. 3 became slightly yellow in color; no change was noted in the color of the others. At the end of four days exposure, all had. assumed the same color, being the same slight yellow as Test No. 3. At the end of eight days exposure (total) the comparison was as follows, in order of lack of change:

Test No. gggfif g'i Results Butyremid Yellow (no change). Furfuramid Faint darkening. Benzamid Appreciable darkening. Dipbenylamine. Cousiderably darker. Benzidine Still darker.

. Formamid Do. No stabilizer Do. Acetamid Darkest (molasses color).

The compounds chosen for the above tests are all amine derivatives and were selected as prospective stabilizers of furfural due to the proved shown that only two of them, butyramid and furfuramid, are useful as stabilizers oi furfural, butyramid being the most eflective, from which tests it is demonstrated that it is a false premise to attribute stabilizing properties with respect to furfural to a class of compounds, but that the stabilizing effect of a compound can only be determined as a matter of trial and error.

What I claim as my invention is:

1. Process of stabilizing normally unstable furiural comprising incorporating in the turfural a modicum of butyramid to substantially inhibit deterioration.

2. Process of stabilizing iurfural comprising incorporating therein approximately 0.01% to 1.0% of butyramid.

3. Process of stabilizing furfural comprising incorporating therein approximately 0.01% to 0.1% of butyramid.

4. A stabilized iurfural comprising normally unstable furfural containing approximately 0.01% to 1.0% of butyramid.

5. A stabilized iuri'ural comprising normally unstable furfural containing approximately 0.01% to 0.1% of butyramid.

6. A stabilized rurfural comprising normally unsigble furfural containing a modicum of butyrami ROCK L. COMSTOCK.