|Title of Invention||
A PROCESS FOR THE PREPARATION OF METAL FORMETES USEFUL FOR MAKING FORMIC AND OXALIC ACIDS.
|Abstract||The present invention relates with a process for the preparation of metal formats useful for making formic acid, oxalic acid etc. In this process an aqueous solution of alkali metal hydroxide is reacted with carbon mono oxide gas used from bio-mass gas, fuel gas, coal gas etc; considering as a cheap source.|
|Full Text||The present invention relates to a process for the preparation of metal formates useful for making formic and oxalic acids.
The present invention particularly relates to a process for the preparation of metal formates useful for making formic and oxalic acid and metal hydroxides under aqueous conditions.
Main usages of this invention are in phosphorous manufacturing plants wherein carbon monoxide gas is obtained as a byproduct. This process could also be used wherever the source of carbon monoxide is available. Metal formates are manufactured usually by reacting metal salts or their oxides with formic acid. Sodium formate is obtained by reacting sodium salts with formic acid. This invention relates to the preparation of metal formates such as sodium formate by reacting with carbon monoxide gas and sodium hydroxide under aqueous conditions at elevated temperature and pressure. This invention could also be used in preventing pollution arising out of carbon monoxide release into the atmosphere. Sodium formate is a source for the preparation of formic and oxalic acids by the known processes.
Formic acid is mainly prepared as a by-product of liquid phase oxidation of hydrocarbons to acetic acid. For example butane and naphtha is oxidized to acetic and formic acids and formic acid is recovered from the crude products. Formic acid recovery is complicated because it esterifies any alcohols present more readily than acetic acid. About one third of the world formic acid produced is based on methyl formate via forma-
mide (Encyclopedia of Chemical Technology, Kirk - Othmer, Vol 11, published by John Wily and Sons, New York) which is easily hydro-lysed in the presence of sulfuric acid to formic acid and ammonium sulfate ( U.S Department of Commerce, PB-952, PB-5077, PB-44962, National Technical Information Service, Springfield, Va., 1947 ). Another route for formic acid from methyl formate involves direct hydrolysis, the reverse of esterification ( K.Tokue, S. Okajima, H.Goto, and H.Tachibana, Kogyo Kagaku Zasshi., 66, 1814 (1963)). In principle carbon monoxide and methanol give methyl formate and in a second step - the ester is hydrolysed to methanol and formic acid which are separated. The net result is represented by the following equations.
CO + CH3OH > HCOOCH3
HCOOCH3 + H20 > CH3OH + HCOOH
Formic acid is also prepared from sodium formate using sulfuric acid or other cheap industrial source of an acid in several small plants throughout the world. Stoichiometric amounts of sodium formate and sulfuric acid are passed through an automatic balance pump at 35OC. The product is metered continuously into an evaporator where the formic acid is distilled and sodium sulfate recovered ( R.Linarte Lazcano and F.B.L Rivera, Rev. Inst. Mex. Pet. 6 (3), 31 (1974)). Electrodialysis of sodium formate in a cell fitted with an ion selective permeable membrane can be used to produce sodium hydroxide and formic acid. In a new process designed at the RCA, laboratories in Princeton N.J., U.S.A carbon dioxide in water is electrochemically reduced to formic acid liberating oxygen at the anode ( Fr. Pat. 1,429,084 (Feb.
18,1966), to Skanska Attikfabriken Aktiebolag).
Oxalic acid is commercially synthesised by alkali fusion i.e nitric acid oxidation of carbohydrates ( Process evaluation and Research Planning Services Second Quarterly Report- 1974, Chem. System. Inc., New York, 1974, PP. 201 - 204., In U.S.A). Oxalic acid is produced primarily from corn starch and the lesser amount from ethylene glycol by an atmospheric one step nitric acid oxidation process in the presence of iron/ vanadium catalyst and sulfuric acid as shown below:
Carbohydrate or starch
Mitsubishi Gas Chemical Co. and Ube Industries Ltd. produce oxalic acid mainly from ethylene glycol by their one step high pressure nitric acid oxidation process. The reaction is given the following scheme.
3 C2H602 + 2 HN03 > C2H204.2H2O + H2O + N2O
Principle raw materials required for the preparation of formic and oxalic acids are metal formate ( for example sodium
.formate) and therefore, the economy of the process depends on the methods and the sources of raw materials used in the preparation of metal formates. Metal formates are generally manufactured by reacting metal salts or their oxides with formic acid. Many of the processes reported in the literature have been either uneconomical or abandoned because of the above reasons. Hence, finding an economically viable route for the preparation of metal formates or formic and oxalic acids derivatives remains always a challenging problem.
The main object of the present invention is to provide a process for the preparation of metal formates useful for making formic and oxalic acids.
Another object is to provide an economical route using
carbon monoxide gas (source from coal gas,for flude gases from
industries containing carbon monoxide gas from the industrial establishments, etc.), considering it as a cheap source for the preparation of metal formates and converting these into formic and oxalic acids by conventional processes.
Accordingly the present invention provides a process for the preparation of metal formates useful for making formic and oxalic acids, which comprises preparing an aqueous solution of an alkali metal hydroxide at a pressure in the range of 10 to 100 atm, at a temperature in the range 50 to 200 degree centigrade for a period of 2 to 5 hrs, cooling the reaction mixture, evaporating the water, followed by drying the resultant metal formate.
The alkali metal hydroxide used may be such as sodium hydroxide, potassium hydroxide and lithium hydroxide.
The carbon monoxide used may be mostly pure CO gas, flue gas, bio-mass gas consisting of CO gas or any other source of CO gas.
The present invention provides a process for the preparation of metal formates using carbon monoxide and metal hydroxides useful for making formic and oxalic acids under aqueous conditions .
Starting materials and its broad details used in this process:
Metal hydroxide : Alkali metal hydroxides.
Carbon monoxide : Pure gas, fuel gas, bio - mass gas
consisting of carbon monoxide gas or any other source of carbon monoxide gas.
: Pressure reactor made up of stainless steel with glass or teflon coating.
-. Sulfuric acid or any other source of an industrial acids.
The essential steps are given in the form of chemicals equation.
Where, M2 = Alkaline earth metal and M1 (OH) is recycled for use in the first stage
The present invention consists of a non catalytic process for the preparation of metal formates from which formic and oxalic acids may be prepared by conventional methods. The above process could be used to prepare a primary source of formic and oxalic acids i.e. metal formates such as sodium formate using metal hydroxides and any source of carbon monoxide gas under carbon monoxide pressure and temperatures in the range 10 - 100 atm. and 50 - 200°C, respectively. Reactor made up of stainless steel or any other material which has resistance towards alkali corrosion is used in this process. Teflon or glass lined pressure reactor is preferred for the preparation of metal formates.
The following example is given by way of illustration and should not be construed to limit the scope of the present invention.
16 g sodium hydroxide was dissolved in 50 ml water and placed in a pressure reactor. Reaction mixture was flushed twice with carbon monoxide gas and the reactor was then pressurized with 10 atm pressure of carbon monoxide gas and heated to 120 °C temperature for 5 hr. After this reactor was cooled to room temperature and water was removed by evaporation. Resulting sodium formate was dried in an oven for 1 hr. Sodium formate thus obtained was converted into formic and oxalic acids as described in the scheme ( second to fifth stage ) of the above text.
1. A process for the preparation of metal formates useful for making
formic and oxalic acid, which comprises preparing an aqueous
solution of an alkali metal hydroxide and reacting with carbon
monoxide at a pressure in the range 10 to 100 atm, at a
temperature in the range of 50 to 200°C for a period of 2 to 5 hrs,
cooling the reaction mixture, evaporating the water followed by
drying the resultant metal formate.
2. A process as claimed in claim 1, wherein the alkali metal hydroxide
used is sodium hydroxide, potassium hydroxide and lithium
3. A process as claimed in claim 1, wherein the carbon monoxide [CO]
used is such as pure CO gas, fuel gas, biomass gas consisting of
4. A process for the preparation of metal formates useful for making
formic and oxalic acid substantially as herein described with
reference to the examples.
|Indian Patent Application Number||2524/DEL/1998|
|PG Journal Number||10/2008|
|Date of Filing||26-Aug-1998|
|Name of Patentee||COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH|
|Applicant Address||RAFI MARG, NEW DELHI-110001|
|PCT International Classification Number||C07C 53/00|
|PCT International Application Number||N/A|
|PCT International Filing date|