SYNTHETIC TAR ACIDS OTHER THAN PHENOL

Certain synthetic tar acids other than synthetic phenol are used commercially in the manufacture of synthetic resins in the United States. Among these are para tertiary amyl phenol, para tertiary butyl phenol, ortho phenyl phenol, para phenyl phenol, and resorcinal.

Para tertiary amyl phenol.

Para tertiary amyl phenol is made by reacting amylene with phenol in the presence of sulphuric acid as a catalyst. At ordinary temperatures it is a solid, melting at about 88° C. and boiling between 250°-265° C. Its use is of increasing importance as a component in tar-acid resins, especially in oil-soluble varnish resins. Owing to its phenol coefficient of approximately 60, it is also used as a germicide, fumigant, and insecticide. Commercial production was reported for the first time in 1933. Since then the output has increased appreciably each year, accompanied by material reductions in sales prices.

According to United States Patent No. 1,800,295, dated April 14, 1931, a resin fast to light and soluble in oils is obtained by heating 82 parts of p-tertiary amyl phenol with 90 parts of formaldehyde, in the presence of sodium hydroxide. This substituted phenol resin passes slowly into the infusible state, thus permitting better control of the reaction.

Para tertiary butyl phenol.

Para tertiary butyl phenol is a white solid with an aromatic odor, melting at approximately 100° C. It is a new commercial product and is used in resins for paints and varnishes. It is the most important resin material in this group.

Phenyl phenols.

Both ortho and para phenyl phenol are commercially produced and are used to some extent in resins to replace phenol. The ortho isomer is a white solid boiling at 284° C. and melting at about 56° C. It is used chiefly as a germicide, though small quantities are used in resins.

Para phenyl phenol is a white solid melting at about 165° C. and boiling at 322° C. Commercial production was reported for the first time in 1933. The output has increased each year since and the selling price has gradually declined.

Resorcinol.

Resorcinol, usually obtained by fusing meta benzene disulphonic acid with caustic soda, is a colorless, crystalline substance with a peculiar odor. It melts at 119° C. and boils at 276° C. It is used in medicine, in the manufacture of intermediates and dyes, and to some extent in synthetic resins. Resorcinol condenses with formaldehyde at such a rapid rate that some means must be applied to slow up the reaction. It is used to increase the rate of condensation of tar-acid resins and to reduce the danger of sticking or undercure.

Domestic production of resorcinol has decreased in recent years. Its relatively high cost is probably an important factor in limiting its use in synthetic resins.