| 摘要 |
<p>Pentaerythritol formaldehyde acetals, which are formed in the production of pentaerythritol as by-products, are cracked by a continuous process, wherein an aqueous solution containing the said acetals acidified with formic acid or other acid which excludes sulphuric, nitric and hydrochloric acids to a pH below 5, the acidified solution being subjected continuously to a heat-treatment at a temperature of at least 150 DEG C. to crack the said acetals. It is preferable to remove excess formaldehyde contained in the acidified solution prior to cracking. The aqueous solution may be obtained by dissolving in water crude pentaerythritol containing said acetals, or may be a mother liquor derived from the preparation of pentaerythritol by condensation of formaldehyde and acetaldehyde, preferably in a ratio of more than 4:1. Specified acids which may be used include oxalic, tartaric, benzenesulphonic, and sulphurous acid. The Specification describes examples of operation of the process of the invention on the laboratory scale.</p> |
