This section is from the book "Alcohol, Its Production, Properties, Chemistry, And Industrial Applications", by Charles Simmonds. Also available from Amazon: Alcohol: Its Production, Properties, Chemistry, And Industrial Applications.
The analysis of industrial methylated spirit is carried out in the way already described for the mineralised variety-omitting, of course, the parts relating to mineral naphtha. In estimating the methyl alcohol by Denigess process, after diluting the spirit with water to 10 per cent. alcoholic strength, it will only be necessary to dilute further ten-fold with 10 per cent. ethyl alcohol, since the proportion of methyl alcohol is only one-half of that in the mineralised spirit.
In order to obtain authority for the receipt of industrial methylated spirit to be used in manufactures, application should in the first instance be made to the local Surveyor of Customs and Excise, who will supply a form of application and give the applicant all necessary preliminary information. Provision must be made for the proper storage of the spirit, and certain premises are ineligible - e.g., those on which spirituous liquors are distilled, or sold for consumption on the premises. Where the quantity of industrial spirit required is more than 50 gallons a year, a bond for the propel use of the spirit must usually be given. This may be done either with personal sureties or through an approved guarantee society. Where a still is kept, and in other special cases, bond may be required for smaller quantities than 50 gallons. Authority to receive the spirit is sent from headquarters after the Surveyor has forwarded the completed form of application and his report upon it. When the authority has been granted, the recipient is supplied with a book of "requisitions" enabling him to obtain the spirit from a methylator; no industrial methylated spirit is obtainable without an official requisition. Occasional inspections of the premises are made, to ascertain that the spirit is not being used in contravention of the authorisation; but on the whole the regulations are not unduly irksome. On the contrary, manufacturers testify that they work quite smoothly and easily.
As a temporary war measure, in order to conserve the supplies of wood-naphtha, the composition of methylated spirit was modified in June, 1918. Two kinds of "industrial" methylated spirit were issued:
(1) "Ordinary," composed of: -
Wood naphtha .................................
Mineral ,, .................................
(2) " Special," composed of: -
Wood naphtha ..................................
The composition of "mineralised " methylated spirit was altered by reducing the proportion of wood naphtha from 10 per cent. to 5 per cent., slightly increasing the percentage of mineral naphtha, and colouring the mixture with methyl violet. The product was thus composed of: -
Wood naphtha .................................
together with an addition of 0.5 per cent. of mineral naphtha; and to each 100 gallons of the product, 0.025 of an ounce of the aniline dye, methyl violet. Except as regards the colouring matter, these modifications were withdrawn in January, 1919.
(3) specially-denatured alcohol the art or manufacture, and for no other purpose, and the spirits so used shall be exempt from duty. . . .
Section 8 of the Finance Act, 1902, which forms the legal authority for allowing in certain cases denatured alcohol other than methylated spirit to be used free of duty, runs as follows: -
"(1). - Where, in the case of any art or manufacture carried on by any person in which the use of spirits is required, it shall be proved to the satisfaction of the Commissioners of Inland Revenue1 that the use of methylated spirits is unsuitable or detrimental, they may, if they think fit, authorise that person to receive spirits without payment of duty for use in the art or manufacture upon giving security to their satisfaction that he will use the spirits in
1 Now the Commissioners of Customs and Excise.
"(2). - The authority shall only be granted subject to a compliance with such regulations as the Commissioners may require the applicant to observe for the security of the revenue, and upon condition that he will, to the satisfaction of the Commissioners if so required by them, render the spirits unpotable before and during use. . . ."
It will be seen that the Commissioners of Customs and Excise have absolute discretion in the matter of sanctioning the use of this variety of alcohol. A condition sine qua non is that methylated spirit must be "unsuitable or detrimental" for the particular purpose to which it is proposed to put the alcohol. Of course, the Commissioners must themselves be the judges of what constitutes unsuitability in the sense of the enactment. That it must be a bona fide unsuitability need scarcely be said. It has to be borne in mind that for the great majority of uses to which industrial alcohol is put, the methyl alcohol in methylated spirit is just as serviceable as the ethyl alcohol; and that although industrial methylated spirit, for instance, is denatured with 5 per cent. of "wood naphtha," yet four-fifths of this is methyl alcohol. In fact, as a glance at its composition (p. 296) will show, the substances other than alcohols and water in industrial methylated spirit are very small in amount, totalling to about 0 6 per cent. only. Hence there are, relatively, not a great many manufacturing requirements for which this form of industrial alcohol is in any substantial sense detrimental.
Some such requirements, however, there are. In these cases, arrangements are made for applicants to receive alcohol under bond, to be denatured at the place of use with some special denaturant suitable to the manufacture in question. The de-naturant may have no particular relation to the manufacture, but may be chosen simply to render the alcohol unpotable during use - for example, bone oil in the making of fulminates. On the other hand the denaturant may be, and often is, some substance which is employed in the manufacture itself, such as aniline in the prepara-tion of aniline dyestuffs.
Thus there is considerable latitude possible in the choice of denaturants to suit special circumstances. In fact, one of the conclusions of the Industrial Alcohol Committee1 is that "Where spirit is used for industrial purposes, the Finance Act of 1902 provides adequate and entirely satisfactory machinery for securing that the spirit may be used in a condition that is suitable and appropriate to each particular purpose of manufacture. The machinery is elastic - much more so than is the corresponding machinery in Germany - and it permits of every reasonable process of denaturing, or even, in the last resort, of the use of spirit in a pure state. For more than this it would be impossible to ask."