A PROCESS (II) FOR MAKING POTASSIUM FORMATE

Abstract: A process for making potassium formate, whereby potassium formate and neopentyl glycol yield from a reaction between formaldehyde and potassium hydroxide in the presence of isobutyric aldehyde. The reaction is carried out in a liquid, preferably aqueous, state at a molar ratio formaldehyde to potassium hydroxide to isobutyric aldehyde of 1.0: 1.0: 1.0: to 3.0: 2.0: 1.0 and at a temperature of 0-100 DEG C.

Description: A PROCESS (II) FOR MAKING POTASSIUM FORMATE The present invention relates to a process for making potas¬ sium formate from formaldehyde and potassium hydroxide in the presence of isobutyric aldehyde. Potassium formate is, among other applications, used as a component in well servicing fluids, such as drilling fluids, for land based as well as offshore oil drilling. Well dril¬ ling depends on many factors, such as the performance of used well servicing fluids. Drilling fluids prevent uncontrolled influx of formation fluids into the well, removes formation cuttings from beneath the bit and transports them to the surface, seals exposed permeable formations, maintains the stability of exposed formations, cools and lubricates the bit and the drill string at points of contact with the cased or uncased drill hole and helps to suspend the weight of the drill string and casing. A number of physical and chemical properties including the rheological properties, of drilling fluids are monitored to ensure satisfactory performance. A major problem is created when the viscosity reduces with increasing temperature. The rheological properties of poly¬ mers, included in drilling fluids as for instance viscosi- fiers, are often substantially degraded or even lost with an increasing temperature. A well known method of stabili¬ sing rheological properties are the combination of brines, such as chlorides and formates of alkali metals, and poly¬ mers, which increases the critical temperature of the poly¬ mer. Potassium formate has been found to exhibit excellent stabilising properties at high temperatures resulting in a critical temperature exceeding 200°C, as disclosed in the research report "High Temperature Stabilisation of Xanthan in Drilling Fluids by the Use of Formate Salts" by J.D. Downs - Koninklijke/Shell Exploratie en Produktie Laboratorium, The Netherlands - Physical Chemistry of Coloids and Interfaces in Production, Paris 1992 pages 197-202. J.D. Downs gives in said paper a detailed disclosure of formates and their stabi¬ lising effect. Furthermore, the European Patent Applications 269 939 and 572 113 also disclose the use of formates in drilling fluids. Potassium formate is very suitable to use as a component in drilling fluids. The salt provides a high density, required for deep well drilling, has a solubility in water exceeding that of other formates and is environmentally safe. Potassium formate is produced by reacting carbon monoxide with potassium hydroxide in accordance with Reaction I below. Reaction I: CO + KOH > HCOOK The production method according to Reaction I is disclosed in Enclyclopedia of Chemical Technology, 3rd. edition, volume 18, page 938. The reaction is fairly slow and carried out by absorbing carbon monoxide, freed of acidic gases, in 50-80% by weight of potassium hydroxide at 100-200°C and at a pres¬ sure of CO > 690 kPa (> 100 psi). The disadvantages of produ¬ cing potassium formate in accordance therewith are obvious and can be summarised: High temperature, high pressure and slow reaction. A high yielding, reliable and industrially applicable process for making potassium formate is presently not available and the availability of said compound is thus limited, being for instance a recovered by-product. Potassium formate can naturally be made by the fundamental but industrially unsuitable or inconvenient reaction between potassium formate and formic acid according to Reaction II below, yielding 1 mole of industrial waste water per mole of potassium formate. Reaction II: HCOOH + KOH > HCOOK + H 2 0 The present invention provides a high yielding, reliable and fast process for making potassium formate in an industrially suitable and convenient way. The process yields potassium formate and neopentyl glycol from a reaction between formal¬ dehyde and potassium hydroxide in the presence of isobutyric aldehyde. The reaction is carried out in a liquid, preferably aqueous, state at a molar ratio formaldehyde to potassium hydroxide to isobutyric aldehyde of 1.0:1.0:1.0-3.0:2.0:1.0, such as 1.5:1.2:1.0-2.5:1.7:1.0 or 1.8:1.0:1.0-2.2:1.5:1.0, and at a temperature of 0-100°C, such as 5-90°C or 30-70°C. Yielded potassium formate is suitably recovered by means of for instance a fractional crystallisation, an ion exchanging procedure, an extraction, a phase separation or an electro- dialysis. The reaction according to the process of the invention has a major advantage in being irreversible. The reaction occurs in accordance with Reaction III below, whereby 2 moles of form¬ aldehyde and 1 mole of potassium hydroxide in the presence of 1 mole of isobutyric aldehyde yield 1 mole of potassium for¬ mate and 1 mole of neopentyl glycol. Reaction III: 2 HCHO + KOH + CH 3 CH(CH 3 )CHO > HCOOK + CH 2 OHC(CH 3 ) 2 CH 2 OH The reaction is preferably carried out at atmospheric pres¬ sure, but can also advantageously be carried out at a reduced pressure, such as less than 760 mm Hg or less than 100 mm Hg, or at an increased pressure, such as 760-2000 mm Hg or even higher. The reaction temperature is suitably adjusted in re¬ lation to the pressure. The process can preferably be carried out as a batch process, whereby an aqueous potassium hydroxide solution and the iso- butyric aldehyde are added to an aqueous formaldehyde solu¬ tion. The potassium hydroxide solution is, in preferred embodiments, added to the formaldehyde solution during at most 60 minutes, preferably at most 30 minutes, and prior to addition of the isobutyric aldehyde. The isobutyric alde¬ hyde is in such embodiments after the addition of the potas¬ sium hydroxide solution added during at most 60 minutes, preferably during 5-30 minutes. The to the addition times subsequent reaction time is normally within the interval of 1-90 minutes, preferably within the interval of 1-30 minutes. The formaldehyde solution has preferably a formaldehyde per¬ centage of 5-65%, such as 10-20% or 30-45%, by weight and corresponding percentage potassium hydroxide is suitably 20-60%, preferably 30-50%, by weight of the potassium hydro¬ xide solution. The process is, when an excess of potassium hydroxide over formaldehyde is used, suitably terminated by a neutralisation with an acid, such as formic acid. Said addition and reaction time as well as said percentages and neutralisation are of course valid also for other embodi¬ ments of the invention not being batch processes, such as a continuous process. The process according to the invention normally converts at least 90% of the theoretically convertible formaldehyde into potassium formate. The high degree of conversion is a result of the fact that the reaction, as disclosed above, is irre¬ versible. A further major advantage of the process according to the in¬ vention is the yielded neopentyl glycol, which is a commer¬ cially valuable product. Neopentyl glycol is an important raw material, direct or indirect, in the production of a large number of substances including saturated and unsaturated po¬ lyesters; polyurethane foams, elastomers and resins; synthe¬ tic lubricants; thickening agents; antioxidants; and pharma- ceuticals. Neopentyl glycol can be recovered from resulting reaction mixture by means of known methods such as distilla¬ tion, extraction and phase separation. The process gives thus two commercially, chemically and industrially very important compounds. The major advantages of the process according to the present invention, furthermore, include a fast and simple reaction, a low reaction temperature, atmospheric, a high degree of con¬ version and no by-products creating waste problems; all enab¬ ling a safe, reliable and industrially as well as commercial¬ ly suitable and convenient production of large quantities of potassium formate. These and other objects and the attendant advantages will be more fully understood from the detailed description, taken in conjunction with below embodiment example, wherein potassium formate is prepared by an embodiment of the process according to the present invention. EXAMPLE 1014.7 g of an aqueous formaldehyde solution (2.30 moles of formaldehyde) having a formaldehyde content of 6.8% by weight were charged in a reaction vessel equipped with a cooler pro¬ vided with a receiver, a stirrer, a pressure gauge and means for the heating and cooling of the vessel. 140.3 g of an aqueous potassium hydroxide solution (1.15 mole of potassium hydroxide) having a potassium hydroxide content of 46% by weight were rapidly, ~ 15 minutes, added to the formaldehyde solution. 73.0 g (1 mole) of a 98.6% isobutyric aldehyde were subsequent the addition of potassium hydroxide during 37 min. added to obtained formaldehyde/potassium hydroxide mixture. The temperature increased exotherically during the addition of isobutyric aldehyde from » 23°C to 46°C and the vessel were cooled to maintain a temperature of 46°C. The reaction was allowed to continue at 46°C for 5 minutes. The vessel walls were now rinsed with a minor amount of water and the reaction mixture neutralised by addition of 2 g of formic acid with a concentration of 85%. The process resulted in 91.5 g of potassium formate and 102.3 g of neopentyl glycol. The recovered quantity of potassium formate can be derived as follows: 3.6 g - yielded from neutralisation with formic acid. 87.9 g - yielded from the reaction between formaldehyde and potassium hydroxide. Equals a conversion of « 90.9% of the formaldehyde to potassium formate (possible losses in connection with reaction, material hand¬ ling and analyses are not regarded) . The theoretical amount is 96.7 g = 1.15 mole. While a particular and preferred embodiment of the invention has been shown, it will be understood, of course, that the invention is not limited thereto since many modifications may be made, and it is, therefore, contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention.

Claims: CLAIMS 1. A process for making potassium formate c h a r a c t e r i s e d i n, that the potassium formate and neopentyl glycol yield from a reaction between formaldehyde and potassium hydroxide in the presence of isobutyric aldehyde, the reaction being carried out in a liquid, preferably aqueous, state at a molar ratio formaldehyde to potassium hydroxide to iso¬ butyric aldehyde of 1.0:1.0:1.0 to 3.0:2.0:1.0, such as 1.5:1.2:1.0 to 2.5:1.7:1.0 or 1.8:1.0:1.0 to 2.2:1.5:1.0, and at a temperature of 0-100°C, preferably 30-70°C. 2. A process according to claim 1 c h a r a c t e r i s e d i n, that yielded potassium formate is recovered by means of an ion exchanging procedure, an extraction, a phase separation, an electrodialysis or a fractional crystallisation. 3. A process according to claim 1 or 2 c h a r a c t e r i s e d i n, that the reaction is carried out at atmospheric pressure. 4. A process according to claim 1 or 2 c h a r a c t e r i s e d i n, that the reaction is carried out at a pressure of less than 760 mm Hg, preferably less than 100 mm Hg. 5. A process according to claim 1 or 2 c h a r a c t e r i s e d i n, that the reaction is carried out at a pressure of more than 760 mm Hg and preferably less than 2000 mm Hg. 6. A process according to any of the claims 1 - 5 c h a r a c t e r i s e d i n, that the process is a batch process, whereby an aqueous potas¬ sium hydroxide solution and isobutyric aldehyde are added to an aqueous formaldehyde solution. 7. A process according to claim 6 c h a r a c t e r i s e d i n, that the potassium hydroxide solution prior to addition of the isobutyric aldehyde is added to the formaldehyde solution during at most 60, preferably during at most 30, minutes. 8. A process according to claim 7 c h a r a c t e r i s e d i n, that isobutyric aldehyde subsequent addition of the potassium hydroxide solution is added during at most 60, preferably during 5-30, minutes. 9. A process according to any of the claims 6 - 8 c h a r a c t e r i s e d i n, that the formaldehyde solution has a formaldehyde percentage of 5-65%, such as 10-20% or 30-45%, by weight. 10. A process according to any of the claims 6 - 9 c h a r a c t e r i s e d i n, that the potassium hydroxide solution has a potassium hydro¬ xide percentage of 20-60%, preferably 30-50%, by weight. 11. A process according to any of the claims 6 - 10 c h a r a c t e r i s e d i n, that the process is carried out at a molar ratio formaldehyde to potassium hydroxide of 1:1 to 2:1 and that the process is terminated by neutralisation with an acid, preferably formic acid. 12. A process according to any of the claims 1 - 11 c h a r a c t e r i s e d i n, that at least 90% of theoretically convertible formaldehyde is converted into potassium formate.

Inventors: ERLANDSSON LARS, JOHANSSON SIGVARD, ERLANDSSON, LARS, JOHANSSON, SIGVARD
Applicants: ERLANDSSON LARS, JOHANSSON SIGVARD, PERSTORP AB, ERLANDSSON, LARS, JOHANSSON, SIGVARD
Application year: 1995
Main classification: C07C53
IPC codes: C07C29, C07C51, C07C53