Definition

GENERAL STATEMENT OF CLASS SUBJECT MATTER

This is the residual class for processes for separating a liquid mixture (distilland) by vaporizing and condensing at least a portion thereof to isolate in the condensed liquid (distillate) or in the unvaporized portion (residue) a comparatively pure compound which was present as such in the original mixture. The original mixture may be a solid under normal atmospheric conditions if it liquifies below the vaporization temperature.

To come within the purview of this class (203) the distilland must have a boiling point above 0°C. under normal atmospheric pressure. Because the C4 hydrocarbons have boiling points above and below 0°C., all C4 hydrocarbons are arbitrarily classified as having boiling points above 0°C.

Sublimination (see Glossary) is excluded from this class (203). See References to Other Classes, below.

When claims are presented which recite a specific chemical compound or mixture to be recovered, the enumerated classifications set forth in Lines With Other Classes must be consulted to see if such subject matter is provided for in other than Class 203.

Lines with other classes and within this class

LINES WITH CHEMICAL COMPOSITION CLASSES

(1) Products whether claimed in terms of their composition or claimed in terms of the process of making are classified in the appropriate composition class even if the process merely recites a separatory distillation operation.

(2) Processes including a chemical reaction and a separatory distillation operation are classified here only when the chemical reaction merely facilitates the isolation by the separatory distillation operation of a preexisting substance in the distilland. See Class 260, Chemistry of Carbon Compounds, Class 423, Chemistry of Inorganic Compounds, or Class 585, Chemistry of Hydrocarbon Compounds for a process of preparing a compound and isolating it by a separatory distillation process.

(3) Processes including a separatory distillation step and a disparate physical separation step, such as extraction, are classified in this class (203) if the disparate separating step follows the distillation step and the process is not otherwise provided for. When the disparate separation step precedes the distillation step, the process is generally provided for elsewhere.

See Class 260, Chemistry of Carbon Compounds (including Class 585, Chemistry of Hydrocarbon Compounds) or Class 423, Chemistry of Inorganic Componds, for a process of extraction of a compound, either as a sole step or followed by isolating the compound by a separatory distillation process.

(4) Processes directed solely to a separatory distillation operation are classified in this class (203) unless otherwise provided for:

(a) Processes for the distillation of metals, such as mercury or zinc are classified in Class 75, Specialized Metallurgical Processes, Compositions for Use Therein, Consolidated Metal Powder Compositions, and Loose Metal Particulate Mixtures.

(b) Processes for distilling a mineral oil in which the product isolated is a pure compound are classified in this class (203). However, when the distillation process produces as the product a mineral oil, it is classified in Class 208, Mineral Oils: Processes and Products.

(c) Processes which include fermentation are classified in 435, Chemistry: Molecular Biology and Microbiology, even if such processes also include distillation.

(d) Processes for distilling fermented beverage to produce a distilled beverage are classified in Class 426, Food or Edible Material: Processes, Compositions, and Products, but processes for distilling a fermented beverage to isolate alcohol are classified here (203).

(e) When a patent contains a Class 423, Chemistry of Inorganic Compounds, process claim and a Class 203, Distillation: Processes, Separatory, process claim, the patent is classified in Class 423 and cross-referenced to Class 203.

PROCESSES INCLUDING EVAPORATION

Processes for evaporating without a condensing step are generally excluded from this class. For specific lines between the processes of this class and other processes including an evaporating step, see below.

This class (203) is distinguished from Class 34, Drying and Gas or Vapor Contact With Solids, in that the material treated herein (203) is a liquid or a liquefiable solid from which volatile material is to be separated and condensed or absorbed. The product recovered must be a relatively pure substance which existed as such in the original material. The material of Class 34 is a solid or semi-solid from which it is desired to remove a liquid, leaving the residue chemically unchanged.

Class 134, Cleaning and Liquid Contact With Solids, takes claimed combinations of work handling or supporting means or steps with means or steps to apply a liquid to the work, as by spraying or immersion, where said liquid is distilled or evaporated, whether or not the resulting vapor is (1) directly contacted with the work or (2) condensed for reuse to contact the work. When only the liquid distillation subcombination or the vapor-phase work contact subcombination has been claimed, see above for the line between Class 203 and Class 34.

Class 62, Refrigeration, includes processes for separating a mixture of substances having boiling points below 0°C. (32°F) at atmospheric pressure by the steps of vaporizing a component and condensing the vapor. When a patent includes species claims classifiable in Class 62 and Class 203, it is classified in Class 62 and cross-referenced to Class 203.

Class 95, Gas Separation: Processes, takes processes in which gas is removed from a liquid wherein the gas is normally gaseous at a temperature of 0°C and a pressure of 760 mm Hg (e.g., hydrogen sulfide (H₂S), carbon monoxide (CO), carbon dioxide (CO₂), etc.). The volatile need not be condensed. The line between Class 95 and Class 203 is that a Class 203 operation requires vaporizing and condensing a material which is normally a liquid, while Class 95 does not.

Class 159, Concentrating Evaporators, takes processes for concentrating solids in solution or suspension by volatilizing the liquid. It is distinguished from this class (203) by the fact that the volatile material is not condensed.

Some additional classes which provide for processes that include an evaporating step or a concentrating step are: Class 23, Chemistry: Physical Processes; Class 127, Sugar, Starch, and Carbohydrates; Class 260, Chemistry, Carbon Compounds; Class 426, Food or Edible Material: Processes, Compositions, and Products; Class 520, Synthetic Resins or Natural Rubbers; Class 585, Chemistry of Hydrocarbon Compounds; Class 588, Hazardous or Toxic Waste Destruction or Containment.

CLASS 201, DISTILLATION: PROCESSES, THERMOLYTIC, IS SUPERIOR TO CLASS 203.