Meta-bi-sulphite of Sodium or Potassium.
Year: 1888

page_text: Meta-bi-sulphite of Sodium or Potassium.
We, WILLIAM BRANTINGHAM GILES and ARTHUR SHEARER and FREDERICK GEORGE
ADAIR ROBERTS all of Wharton Road, Stratford in the County of Essex Manufacturing
Chemists do hereby declare the nature of this Invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement:-.
This Invention consists in the manufacture or production of bi-sulphite or meta-
bi-sulphite of Sodium, or of Potassium by passing sulphurous acid gas (SO) over or
through solid Bi-carbonate of Sodium or solid Bicarbonate of potassium the sulphurous
acid being thereby absorbed and bi-sulphite or meta-bi-sulphite of sodium or of
potassium or a mixture of such bi sulphite or meta-bi-sulphite is produced.
We have found that the chemical constitution of the product of the said operation
varies accordingly as whether means are taken to refrigerate the vessel in which the
operation is performed or on the other hand the temperature is allowed to rise or
means are taken to heat the vessel as hereinafter explained. If the vessel containing
the Bicarbonate is refrigerated so as to keep the mass of material operated upon at
or below 60° Fahrenheit during the passage of the sulphurous acid gas the following
chemical reaction takes place viz.
if solid bi-carbonate of potassium he employed sodium or potassium bi-sulphite
(Na H SO, or KH SO₂) being the product obtained under the above specified
conditions of temperature.
If however the vessel containing the solid bi-carbonate of sodium or of potassium
be heated so that the material acted upon is kept at a temperature between 212°
and 257° Fabrenheit during the passage of the sulphurous acid the product consists of
sodium (or potassium) meta-bi-sulphite the chemical changes being expressed as
follows:

page_text: 2 (K H (O₂) + 2 SO₂ ==
K, S, 0, + 2 CO₂ + H₂
in the case of solid bi-carbonate of potassium being used meta-bi-sulphite of potassium
being produced.
If no special means of cooling or heating during the operation be taken, the
product will vary in composition according to the form size and material of the vessel
employed and the mass of material operated upon in general if the temperature be
between 60° and 212° Fahrenheit a mixture of Bi-sulphite (K H SO, or Na H SO₂)
and meta-bi-sulphite (Na, S, O, or K, S, O,) is the result the meta-bisulphite being
formed by the rise of temperature caused by the evolution of heat attending chemical
reaction and in some cases it may be that nothing but meta-bi-sulphite carbonic acid
and water will be produced where the form of vessel and other conditions favor
retention of heat and consequent rise of temperature of the material operated upon.
In practice if we desire to produce only Bisulphite of Sodium or of Potassium, we
place solid bi-carbonate of Sodium or Potassium in any suitable vessel and pass
gaseous sulphurous acid over or through the mass of bicarbonate until the latter is
completely decomposed, refrigerating during the operation so that the temperature
inside. the vessel shall not rise above 60° Fahr. The operation is finished when the
material no longer absorbs Sulphurous acid. If necessary the mass is kept stirred to
assist absorption. The refrigerating may be effected in any suitable way such as by
passing cold water through a casing surrounding the vessel or through pipes passing
through it.
If we desire to manufacture only meta-bi-sulphite of Sodium or of Potassium we
conduct the operation as above described except that instead of refrigerating, we by
suitable means such as by hot gases or steam passed through a casing or pipes raise
the temperature of the mass of solid bi-carbonate operated upon to from 212° to
257° Fahrenheit during the operation.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is.
1st. The manufacture or production of bi-sulphite of Sodium or of Potassium or
meta-bi-sulphite of Sodium or of Potassium or mixtures of such bi-sulphites and
meta-bi-sulphites by passing Sulphurous acid gas over or through solid bi-carbonate
of Sodium or solid bi-carbonate of Potassium.
2nd. The manufacture or production of bi-sulphites of Sodium or of Potassium
by passing Sulphurous acid gas over or through solid bi-carbonate of Sodium or
solid bi-carbonate of Potassium maintained at a temperature of 60° Fahrenheit or at a
lower temperature.
3rd. The manufacture or production of meta-bi-sulphite of Sodium or of Potassium
by passing Sulphurous acid gas over or through solid bi-carbonate of Sodium or
solid bi-carbonate of Potassium maintained at a temperature of from 2120 to
257° Fahrenheit.
4th. As new articles or products bi-sulphite or meta-bi-sulphite of Sodium or of
Potassium or mixtures of such bi-sulphite and ineta-bi-sulphite produced as herein-
before described and claimed.
Dated this 30ml dar of Dasomber 188e