Patent GB-397169-A (GB)
Title: Improvements in the separation of paraffin wax or similar waxy substances from oils containing the same
IPC: C10G73/04
Filed: 1932-02-13
Abstract: Condensation or polymerization products of high molecular paraffin hydrocarbons such as hard or soft paraffin wax, ceresin, ozokerit or wax-like derivatives thereof, more particularly oxygen derivatives such as montan wax, are employed to facilitate the separation of waxes from hydrocarbon oils.  Suitable condensation products are made by treating the hydrocarbons with halogens, halogen-exchanging compounds, oxygen, sulphur or other substances capable of introducing thereinto exchangeable constituents or splitting off hydrogen, for example as described in Specification 349,071, and heating the resulting product to 20-100 DEG  C. with a condensing agent such as aluminium, zinc or iron chloride, boron fluoride, phosphorus oxychloride, activated aluminium, sodium or zinc dust.  Condensation may be effected in the presence of surface-active substances such as bleaching earths or active silica, and with reaction retardants, e.g. zinc oxide, soda, calcium carbonate, or ammonia.  Condensation may also be obtained by exposing the materials to the action of the silent electric discharge.  The hydrocarbons or their halogen, oxygen or sulphur compounds may be condensed with cyclic hydrocarbons, e.g. naphthalene, crude benzene, middle tar oils, anthracene oils or hydrogenated or cracked cyclic hydrocarbons.  In the examples given, a product obtained by the condensation of chlorinated paraffin wax with naphthalene is employed.ALSO:Waxes are separated from hydrocarbon oils containing them by adding a condensation or polymerization product of high molecular paraffin hydrocarbons, or wax-like derivatives thereof such as montan wax, cooling the mixture and separating the precipitated waxes.  The process may be used for purifying paraffin wax, petroleum, or crude montan wax by diluting the wax with illuminating or other suitable oil and then treating as above. Suitable condensation products are made by treating the hydrocarbons with halogens, halogen-exchanging compounds, sulphur, oxygen, or other substances capable of introducing thereinto exchangeable constituents or splitting off hydrogen, for example as described in Specification 349,071, and heating the resultant product to 20-100 DEG  C. with a condensing agent such as aluminium, zinc or iron chloride, boron fluoride, phosphorous oxychloride, activated aluminium, sodium or zinc dust.  Condensation may be effected in the presence of surface-active substances such as bleaching earths, or active silica, and with reaction retardants, e.g. zinc oxide, soda, calcium carbonate or ammonia.  The condensation products may be prepared from ceresin, ozokerit or hard or soft paraffin wax or from mildly cracked or dehydrogenated hydrocarbons and may be condensed with cyclic hydrocarbons, e.g. naphthalene, crude benzene, middle tar oils, anthracene oil or hydrogenated or cracked cyclic hydrocarbons. The condensation may be effected by exposing the materials to the action of silent electric discharges.  The separation from the oil of the substances which crystallize out may be obtained by sedimentation, filter pressing or centrifuging.  In removing a mixture of paraffin wax and asphalt the mixture may be separated into its constituents by adding liquid chlorinated hydrocarbons such as trichlorethylene or carbon tetrachloride, preferably in an amount of about one-third of that of the oil and filtering and centrifuging after cooling, the wax remaining as a residue free from asphalt.  In some cases the said liquids or other diluents, e.g. benzene, liquefied gaseous hydrocarbons such as propane, ketones alcohols or benzene-alcohol mixtures or illuminating oils, or mixtures of these liquids, may be added before the separation by cooling, whereby the asphalt remains in the oil and the wax is precipitated substantially free from asphalt.  In addition, other substances which crystallize out when cold, such as naphthalene or anthracene, or solid substances such as bleaching earths or lime may be added to facilitate crystallization out of the wax.  The added substances need not in most cases be removed and in the case of lubricating oils improve the final product by lowering the setting point and improving the temperature-viscosity curve.  The final product may be further improved by addition of further amounts of the substances, especially the condensation products of hard and soft paraffin wax obtained by electrical treatment.  The oil need not be completely freed from wax in view of this lowering of the setting point.  The process enables the use of a smaller amount than hitherto of the diluent employed in precipitating further quantities of the wax and allows cooling of the oil to a lesser extent than before in separating the wax.  Examples are given of the treatment of a lubricating-oil fraction of a German petroleum with a product obtained by condensing chlorinated paraffin wax with naphthalene, and of a brown coal tar fraction diluted with benzene with the same product.