EP0494933A1 - Tetrathiocarbonate process - Google Patents
Tetrathiocarbonate processInfo
- Publication number
- EP0494933A1 EP0494933A1 EP90915039A EP90915039A EP0494933A1 EP 0494933 A1 EP0494933 A1 EP 0494933A1 EP 90915039 A EP90915039 A EP 90915039A EP 90915039 A EP90915039 A EP 90915039A EP 0494933 A1 EP0494933 A1 EP 0494933A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- process according
- hydroxide
- percent
- aqueous solution
- salt
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D13/00—Compounds of sodium or potassium not provided for elsewhere
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D15/00—Lithium compounds
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F5/00—Compounds of magnesium
Definitions
- This invention relates to the manufacture of salts of tetrathiocarbonic acid. In one of its more particular aspects this invention relates to a process for manufacturing aqueous solutions of tetrathio- carbonates on a commercial scale.
- Yeoman reports a further study of thiocarbonates (called trithiocarbonates therein) and also reports the preparation and proper ⁇ ties of perthiocarbonates (or tetrathiocarbonates) , derivatives of tetrathiocarbonic acid (H 2 CS 4 ) .
- Yeoman reports on methods of preparing the ammonium, alkali metal and alkaline earth metal salts of these acid species. For example, Yeoman prepared ammonium trithi ⁇ ocarbonate by saturating an alcoholic ammonia solution with hydrogen sulfide and then adding carbon disulfide to precipitate the product salt.
- Ammonium perthiocar- bonate was prepared in a similar manner, except that after reacting the ammonia and hydrogen sulfide, ele ⁇ mental sulfur was added to form the disulfide, (NH 4 ) 2 S 2 ; adding carbon disulfide immediately precipi ⁇ tated the product.
- Yeoman also attempted to prepare and charac ⁇ terize the stability of thiocarbonate salts of four of the alkaline earth metals. Yeoman was unable to pre ⁇ pare a pure calcium tri- or tetrathiocarbonate, but did observe that the double salt of calcium trithiocarbon ⁇ ate which he prepared was more stable (probably because it was less hygroscopic) than the sodium or potassium thiocarbonates.
- the barium salt of tetrathiocarbonic acid could not be isolated, although Yeoman believed it existed in solution. Solid barium trithiocarbonate could not be isolated, although it was alleged to behave like sodium trithiocarbonate when dissolved in water. The preparation of aqueous solutions of the tri- and tetrathiocarbonates of magnesium and strontium was alleged, but the magnesium thiocarbonates were not isolated.
- Stone et al. disclose several methods for preparing solid ammonium, alkali and alkaline earth metal salts of tri- and tetraperoxythiocarbonates, hereinafter referred to simply as
- tetrathiocarbonates One such method involves the solution of an active metal such as sodium in anhydrous ethanol to form an ethoxide which, in turn, is reacted with hydrogen sulfide and carbon disulfide to form sodium trithiocarbonate. They report, however, that the trithiocarbonates tend to be quite soluble in ethanol, and if it is desired to recover the solid material from the solution, it is necessary to treat the reaction mixture with a "displacing agent" such as ether, in which case the thiocarbonates frequently separate, not as solids, but as difficultly crystalliz- able oils which appear to be saturated aqueous solu ⁇ tions of the trithiocarbonate salt. Consequently, such a procedure is not considered feasible for use on a commercial scale. Similar problems were reported with tetrathiocarbonate salts, which were prepared using procedures analogous to those for the trithiocarbon- ates.
- the present invention provides a process for the production of salts of tetrathiocarbonic acid which is capable of providing aqueous solutions of tetrathio ⁇ carbonates in concentrations useful for various commer ⁇ cial applications, such as in the control of nematodes and other soil-borne and water-borne pathogens.
- the present invention provides a process which is less cumbersome than prior processes and which can be readily practiced in a simple, straight-forward manner.
- tetrathio ⁇ carbonates can be produced in concentrations of upwards of 30 percent in water by means of a batch process in which, for example, sodium hydroxide reacts with hydro ⁇ gen sulfide to produce sodium sulfide in an exothermic reaction; the sodium sulfide thereby produced reacts with elemental sulfur in an endothermic reaction to produce sodium disulfide; and the sodium disulfide thereby produced reacts with carbon disulfide to pro ⁇ cute sodium tetrathiocarbonate in an exothermic reac ⁇ tion.
- aqueous solutions of tetrathiocar ⁇ bonates can be produced in a continuous process in relatively high concentrations, such as about 30 per ⁇ cent by weight or more by continuously feeding water, a hydroxide, sulfur, carbon disulfide and hydrogen sul ⁇ fide; continuously reacting the hydroxide, sulfur, carbon disulfide and hydrogen sulfide; and continuously recovering an aqueous solution of a salt of tetrathio ⁇ carbonic acid.
- Na 2 S + S Na 2 S 2
- Na 2 S 2 + CS 2 Na 2 CS 4 (5)
- Adding water, sodium hydroxide, molten sul ⁇ fur, carbon disulfide and hydrogen sulfide simultane ⁇ ously but separately to a reactor and continuously reacting under controlled conditions results in a product which comprises an aqueous solution having a concentration of 30 percent by weight or more of sodium tetrathiocarbonate.
- tetrathiocarbonate solutions are stable and directly toxic to many plant pathogens, breaking down in soil to release carbon disulfide, which acts as a fumigant.
- Tetrathiocarbonates are biodegradable, producing sulfates and carbonates, and leave no residue in the soil or in plants treated with tetrathiocarbonates.
- a hydroxide, hydrogen sulfide, sulfur and carbon disulfide are reacted in approximately stoichiometric quantities in a water medium to produce aqueous tetra ⁇ thiocarbonate solutions having concentrations of 30 percent by weight or more, preferably concentrations of about 31 percent to about 35 percent by weight.
- the process can be conducted in any conven ⁇ ient reaction vessel in which the reactants can be thoroughly mixed and which can be heated or cooled to control the reaction temperature. Pressure is not a major consideration since pressures in the range of about 15-30 psig. are sufficient for the process. Heating and cooling can be provided by either external or internal heat exchangers.
- a stirred tank reactor, for example, is satisfactory for conducting the process of the present invention.
- a 6000 gallon stirred tank reactor is flushed with nitrogen to provide an inert atmosphere essential ⁇ ly free of oxygen.
- the oxygen level is usually less than about 1.0 percent by weight and preferably less than about 0.3 percent by weight.
- Water is then added to the reactor at a rate of 30,000 lbs./hr. for a period of 46 minutes.
- Sodium hydroxide is added to the reactor in about a 5 percent to about a 15 percent excess, preferably about a 10 percent excess.
- the sodium hydroxide is added as a 50 weight percent solu ⁇ tion at a rate of 22,500 lbs./hr. for a period of 43 minutes in the first stage of the process. This re ⁇ sults in a concentration of about 25 percent by weight. Concentrations of about 10 percent to about 50 percent and preferably about 15 percent to about 35 percent by weight can be used.
- the sodium hydroxide solution is preferably introduced into the reactor above the liquid surface. During this time the temperature rises by about 40° F.
- hydrogen sulfide is added to the sodium hydroxide solution at a rate of 1,600 lbs./hr. for about 2 hours to provide no more than about a 5 percent excess.
- the hydrogen sulfide which is added as a gas, is preferably introduced as near the bottom of the reactor as possible to allow the hydrostatic head of the reactor contents and the agitation to be effective in reacting the hydrogen sulfide with the sodium hy ⁇ droxide (Reaction 3) .
- An excess of hydrogen sulfide over the 5 percent excess mentioned above should be avoided, since the excess hydrogen sulfide will eventu ⁇ ally cause a pressure build-up in the reactor.
- hydrogen sulfide gas may have up to about 1-2 percent by weight of inerts, which will simply cause a pressure build-up in the reactor and can be removed by venting.
- pressure build-up due to inerts can be relieved by venting at the end of the hydrogen sulfide addition.
- the reaction between sodium hydroxide and hydrogen sulfide is exothermic. A tem ⁇ perature rise of about 35° F. results.
- sodium sulfide which is formed upon the addition of hydrogen sulfide to the diluted sodium hydroxide solution in the second stage of the process, begins to precipitate at temperatures below about 90° F.
- the reactor should be maintained at a temperature of at least about 110° F.
- Superatmosphere pressures of about 2.5 psig. to about 10 psig are adequate.
- the heat produced upon mixing the sodium hydroxide solution with water and the exothermic reaction with hydrogen sulfide is usually sufficient to prevent precipitation of the sodium sulfide product.
- the temper ⁇ ature of the reactor following the addition of hydrogen sulfide to the sodium hydroxide solution is insuffi ⁇ cient to keep sodium sulfide in solution
- heat may be added to the reactor by means of a heater or steam jacket to maintain a temperature of about 110° F. Agitation of the reactants is essential during this and succeeding stages.
- the temperature should be above about 140° F. to assure reaction of the sulfur with the sodium sulfide. Temperatures of about 140° to about 170° F. are desirable. Sulfur is added in the molten state at a temperature of about 280° F. , preferably by spraying into the vapor space above the liquid contents of the reactor. The particle size of the sprayed sulfur particles is preferably less than 1/8 inch in diameter. Contact between molten sulfur droplets and metal surfaces inside the reactor should be avoided. Sulfur is added at a rate of 1,500 lbs./hr. for about 2 hours. The reaction of sulfur with sodium sulfide (Reaction 4) is endothermic, resulting in about a 5° F.
- Reaction 4 The reaction of sulfur with sodium sulfide
- reaction 5 For the reaction between sodium disulfide and carbon disulfide (Reaction 5) to proceed at a reasona ⁇ ble rate, a temperature of about 135-140° F. has been found optimum. Temperatures of about 120° to about 160° F. can be used.
- the reactor pressure is typically about 5 psig to about 20 psig, preferably about 10 psig to about 15 psig.
- Carbon disulfide is added below the surface of the liquid reactor contents at a rate of 2,800 lbs./hr. for about 2.5 hours.
- the temperature can be maintained at about 135° to about 140° F., with cooling if necessary, since the reaction is exothermic.
- Venting is undesirable, since the carbon disulfide must be prevented from leaving the reactor in order to insure an optimum yield of sodium tetrathiocarbonate. Consequently, agitation and recirculation of the re ⁇ sulting solution should continue until all the carbon disulfide has reacted, which could take as much as several hours. During the reaction the pressure may rise by about 10 psig to about 20 psig.
- the resulting product is an absolutely clear solution, containing neither unreacted sulfur, which would result in a cloudy product, nor unreacted carbon disulfide, which would appear either as a separate phase or as bubbles of cloudiness.
- the product is orange-red in color and has a slight sulfur odor.
- the specific formulation described above produces 5000 gallons of 31.8 percent by weight of sodium tetrathio ⁇ carbonate in water and has a specific gravity of about 1.20 to about 1.30, typically 1.26 at 70° F.
- the slight excesses of sodium hydroxide and hydrogen sul ⁇ fide utilized in the process of the present invention have been found to help hold the active carbon disul ⁇ fide component more tightly in solution, thereby reduc ⁇ ing odor and making the product more stable.
- a hydroxide, hydrogen sulfide, sulfur and carbon disulfide are reacted continuously in approxi ⁇ mately stoichiometric quantities in a water medium to produce aqueous tetrathiocarbonate solutions preferably having concentrations of about 15 percent by weight or more, more preferably concentrations of about 30 to about 55 percent, and most preferably about 40 to about 50 percent by weight of the tetrathiocarbonate salt. Higher concentrations are particularly desirable be ⁇ cause increased throughputs are possible and shipping costs are lower.
- reactants are typically present in stoichiometric quantities, an excess of about 5 percent to about 10 percent by weight of the hydroxide and hydrogen sulfide have been found desira ⁇ ble to stabilize the product tetrathiocarbonate solu ⁇ tions. Especially preferred are an excess of about 10 percent of the hydroxide and about 5 percent of the hydrogen sulfide.
- the process can be conducted in any conven ⁇ ient reaction vessel in which the reactants can be introduced simultaneously and continuously and thor ⁇ oughly mixed, and in which the reaction temperature can be maintained as desired. Temperature control can be provided by either external or internal heat exchang ⁇ ers. Pressure is not a major consideration. Superat- mospheric pressures, usually in the range of about 5 psig. to about 30 psig. are typically employed. A continuous stirred tank reactor (CSTR) , for example, is ideally suited for conducting the process of the present invention.
- CSTR continuous stirred tank reactor
- a continuous process for the manufacture of sodium tetrathiocarbonate requires that all chemical reactants be essentially completely reacted in order to ensure that the reactions depicted in Reactions (3) , ( 4 ) (5) , (6) and (7) are effective to produce the desired product and to avoid severe operating problems. For instance, if sulfur is not completely reacted, it will remain as a solid and plug product filters and piping. If CS 2 is not completely reacted, it will vaporize and significantly increase the reactor pres ⁇ sure. Moreover, CS 2 will also compete with Na 2 S and Na 2 CS 3 for sulfur, resulting in incomplete reaction and plugging of piping and equipment.
- reaction path In a continuous process all possible reaction paths are competing.
- the dominant reaction path is the one having the fastest global kinetics. Which reaction path will predominate can, to some extent, be deter ⁇ mined by choice of reaction conditions, such as temper ⁇ ature, concentration and residence time. For example, at low temperatures and low concentrations the reaction path which predominates is the path defined by reactions (3) , (6) and (7) , whereas at high temperatures the predominant reaction path is the path defined by reactions (3) , (4) and (5) .
- Reaction (3) which is common to both paths, is an ionic reaction and is very fast. This reaction, which is the fastest reaction in the entire sequence of reactions, is instantaneous and complete.
- reaction 6 If the temperature and the product concentra ⁇ tion are both low, the reaction of CS 2 with Na 2 S (Reaction 6) and the reaction of CS with Na 2 S 2 (Reac ⁇ tion 5) have the next higher reaction rates.
- the reaction rate of Reaction 5 is mass transfer limited and depends upon the concentration of CS 2 in the aque ⁇ ous phase, in which the reaction occurs. This reaction is slower at higher temperatures because the solubility of CS 2 in water decreases with increasing temperature.
- the reaction of Na 2 S with CS 2 (Reaction 6) is kineti- cally limited at low temperatures and increases with increasing temperature until the solubility becomes limiting.
- the slowest reactions and those most sensi ⁇ tive to temperature are the addition of sulfur to Na S (Reaction 4) and the addition of sulfur to Na 2 CS 3 (Reaction 7) .
- molten sulfur is present in the form of an eight-membered ring structure, S 8 , as monoclinic sulfur.
- the effect of heat and the presence of hydroxide ions is to open the sulfur ring, thereby transforming the ringed monoclinic sulfur to a linear form.
- the resulting linear form is either a linear organized structure, rhombic sulfur, or a linear unor- ganized structure, amorphous sulfur.
- Na 2 S or Na 2 CS 3 will swallow the sulfur molecules at one or both ends of the sulfur chain to form, in the case of Na 2 S, a polysulfide, Na 2 s ⁇ such as Na S 2 or, in the case of Na 2 CS 3 , the corresponding tetrathiocarbonate, Na 2 CS 4 .
- Increasing the temperature increases the rate of both sulfur reactions, but particularly the rate of the reaction of sulfur with Na 2 CS 3 , which is the slowest reaction and is rate limiting under most operating conditions.
- the reaction path which predominates at lower temperatures and lower concentrations is there ⁇ fore the path defined by Reactions 3, 6 and 7.
- a continuous process requires thatreactor volume, reactor temperature, reactant feed rates and product compositions be correlated so that sufficient residence time is provided for complete conversion to the desired product.
- the residence time determines the reaction time.
- a continuous process is decidedly advanta ⁇ geous, first and foremost because a continuous process is generally the most convenient and efficient way to conduct chemical reactions, assuming the intended chemical reaction or reactions can be run continuously.
- Production rates of continuous processes can be several times those of batch processes. For exam ⁇ ple, whereas a batch process may be capable of produc ⁇ ing about 4,000 pounds per day of an aqueous solution of sodium tetrathiocarbonate having a concentration of about 30 percent to about 35 percent by weight, the continuous process of the present invention can produce about 15,000-20,000 pounds of product solution per day using the same reactor size.
- Another advantage of the continuous process of the present invention is that it is capable of producing concentrations of sodium tetrathiocarbonate higher than those produced in a batch process, that is, concentrations of up to about 55 percent by weight. Even higher concentrations can be produced using the process of the present invention. However ⁇ at concen ⁇ trations over about 55 percent by weight the reaction rate falls off because the solubility of CS 2 in the aqueous reaction phase is reduced and because carbonate contaminants introduced with the water begin to precip ⁇ itate. The latter problem can be circumvented by using carbonate-free and bicarbonate-free water.
- a continuous stirred tank reactor 10 is equipped with a sulfur feed conduit 12, a water supply conduit 14, a caustic (NaOH) conduit 16, a carbon disulfide conduit 18, a nitrogen (N 2 ) conduit 20 and a hydrogen sulfide conduit 22.
- Conduit 18 extends well into reactor 10.
- Conduit 20 contains a valve 24 and conduit 22 contains a valve 26.
- Reactor 10 is also equipped with a double stirrer 28 attached to a motor 30.
- Reactor 10 is shown containing a solution 32.
- Reactor 10 is fitted with a sight level gauge 34.
- a heat exchanger 36 is connected to reactor 10 via a 3-way temperature control valve 37, a conduit 38, filters 40, a conduit 42, a pump 44 and a conduit 46.
- a conduit 48 also connected to 3-way valve 37, serves as a bypass line for heat exchanger 36.
- a conduit 50 connects heat exchanger 36 to a conduit 52, which serves as a recycle line and a con ⁇ duit 54, which is connected to a level control valve 55, and serves as a connection to storage "tanks, not shown.
- a scrubber 56 is equipped with a caustic tank 58 and a recycle line 60, which is provided with a pump 62. Scrubber 56 is connected to reactor 10 by means of a conduit 64.
- An emergency scrubber 66 is connected to reactor 10 by means of a conduit 68 equipped with a rupture disk type of pressure relief valve 70.
- water is introduced into reactor 10 by means of water supply conduit 14. Although shown entering the top of the reactor, water can be introduced into the reactor at either the top or the bottom. Water is usually introduced at ambient conditions. However, under low temperatures it may be necessary to heat the water in order to prevent freezing.
- the hydroxide is introduced into the reactor at the top or bottom as desired.
- caus ⁇ tic is shown entering reactor 10 at the top via caustic conduit 16.
- the corresponding hydroxide such as sodium hydroxide, potassium hydroxide, ammonia, lithium hydroxide, calcium hydroxide or magnesium hy ⁇ droxide, for example, is introduced as an aqueous solution. Concentrations of about 10 percent to about 70 percent by weight are typically used. Preferably concentrations of about 20 percent to about 60 percent and more preferably about 40 percent to about 50 per ⁇ cent are used.
- the hydroxide can be introduced under ambient conditions. However, it is important that the temperature of the hydroxide feed be kept above its freezing temperature.
- Sulfur is fed into reactor 10 at the top via sulfur feed conduit 12. Sulfur in the molten state is sprayed into the reactor through the vapor space above the surface of the liquid.
- the molten sulfur is normally introduced through a heated nozzle to prevent sulfur from plugging the nozzle in the relatively colder operating temperature of the reactor.
- the molten sulfur is normally introduced at a tempera ⁇ ture of about 250° F. to about 300° F. , preferably about 275° F. to about 285° F.
- particle sizes of the sprayed molten sulfur droplets of about 1/32 inch to about 3/8 inch in diameter are used. Particle sizes of less than about 1/8 inch in diameter have been found to produce the best results.
- Carbon disulfide is introduced into reactor 10 via carbon disulfide conduit 18. It is introduced below the surface of the liquid in the reactor in order to make it available for reaction in solution 32 and to prevent its contacting sulfur particles in the vapor space above solution 32.
- the carbon disul ⁇ fide is introduced close to stirrer 28 to ensure that the carbon disulfide is dispersed in the solution quickly and evenly.
- the carbon disulfide can be intro ⁇ quizzed at ambient conditions.
- Hydrogen sulfide gas is introduced into reactor 10 via hydrogen sulfide conduit 22.
- the volume introduced is regulated by means of valve 26.
- the hydrogen sulfide is preferably sparged into solution 32 below stirrer 28 to ensure thorough mixing within the liquid phase and to take advantage of the hydrostatic head of the liquid within the reactor in effecting complete reaction of the hydrogen sulfide.
- the process is commenced by filling the reactor with a heel of product and purging the vapor space above the solution with nitrogen gas introduced into reactor 10 via nitrogen conduit 20.
- the flow of nitrogen is controlled by means of valve 24.
- Nitrogen exits reactor 10 via conduit 64 which connects reactor 10 with scrubber 56.
- valve 24 is closed to stop the flow of nitrogen.
- Simultane ⁇ ously water, a hydroxide, hydrogen sulfide, molten sulfur and carbon disulfide are fed into the reactor with the result that the tetrathiocarbonate product is produced continuously as long as reactant feed rates are maintained.
- Product is pumped out of reactor 10 by means of pump 44 through conduits 46 and 42 to filters 40 which function to remove any solids such as sulfur from the product stream. Filtered product is flowed to 3- way temperature control valve 37 which maintains the temperature of reactor 10 by directing the product stream either wholly or partly to heat exchanger 36 or bypass conduit 48. Most of the cooler product recycles back to reactor 10 via conduit 52. The rest of the product flows through conduit 54 to level control valve 55 to storage. Level control valve 55 maintains the liquid within reactor 10 at the desired operating level.
- Gases collected in the vapor space of the reac ⁇ tor above the liquid level are vented from the reactor via conduit 64 through caustic scrubber 56.
- An emer ⁇ gency scrubber is provided as shown in the drawing.
- a rupture disk type of pressure relief valve 70 activates emergency scrubber 66 when the pressure within reactor 10 builds up to an unacceptable level.
- reactor volume, reactor temperature, reactant feed rates and product composition are correlated. It is usual to express feed rates in terms of residence times, since residence time is inversely proportional to feed rate.
- residence time is inversely proportional to feed rate.
- the correlation between residence time and temperature of reaction, measured as temperature of the liquid phase, for various product compositions is shown in Table 1.
- temperatures of about 110° F. to about 180° F. at residence times of about 1 to about 7 hours are effective to produce concentrations of product tetrathiocarbonate in the range of about 30 percent by weight to about 55 percent by weight.
- temperatures of about 140° F. to about 150° F. and residence times of about 3 to about 4 hours are preferred.
- a quantity of 140 gallons of a 31.8 percent by weight aqueous solution of sodium tetrathiocarbonate was introduced as a heel into a 200 gallon continuous stirred tank reactor.
- the reactor was purged with nitrogen and heated to 140° F.
- Water at a feed rate of 226 lbs./hr., a 50 percent by weight aqueous solution of sodium hydroxide at a feed rate of 151.1 lbs./hr., molten sulfur at a feed rate of 27.4 lbs./hr., carbon disulfide at a feed rate of 65 lbs./hr. and hydrogen sulfide gas at a feed rate of 30.5 lbs./hr. were con ⁇ tinuously fed into the reactor.
- the molten sulfur was introduced at a temperature of 285° F.
- the reactor was maintained at a temperature of 145° F. and a pressure of 15 psig.
- a 31.8 percent by weight aqueous solution of sodium tetrathiocarbonate at a rate of 500 lbs./hr. was continuously produced.
- the present invention thus provides a contin ⁇ uous process for producing salts of tetrathiocarbonic acid conveniently as stable aqueous solutions of high concentrations, for example, in the range of about 30 to about 55 percent by weight.
- the invention may be embodied in other forms without departing from the spirit or essential charac- teristics thereof.
- other salts of tetrathiocarbonic acid than sodium tetrathiocarbonate can be prepared using the process of the present invention. Consequently the present embod ⁇ iments are to be considered only as being illustrative and not restrictive, with the scope of the invention being indicated by the appended claims. All embodi ⁇ ments which come within the scope and equivalency of the claims are therefore intended to be embraced there ⁇ in.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US41587489A | 1989-10-02 | 1989-10-02 | |
US415874 | 1989-10-02 | ||
US44002489A | 1989-11-21 | 1989-11-21 | |
US440024 | 1999-11-12 |
Publications (1)
Publication Number | Publication Date |
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EP0494933A1 true EP0494933A1 (en) | 1992-07-22 |
Family
ID=27023148
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90915039A Ceased EP0494933A1 (en) | 1989-10-02 | 1990-10-01 | Tetrathiocarbonate process |
Country Status (14)
Country | Link |
---|---|
EP (1) | EP0494933A1 (pt) |
JP (1) | JPH05500498A (pt) |
CN (1) | CN1052851A (pt) |
AP (1) | AP212A (pt) |
AU (1) | AU6519190A (pt) |
BR (1) | BR9007699A (pt) |
CA (1) | CA2067125A1 (pt) |
HU (1) | HUT61250A (pt) |
IL (1) | IL95825A (pt) |
MA (1) | MA21966A1 (pt) |
PT (1) | PT95482B (pt) |
TR (1) | TR24796A (pt) |
WO (1) | WO1991004944A1 (pt) |
YU (1) | YU184890A (pt) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2690691B1 (fr) * | 1992-04-29 | 1999-02-12 | Bio Merieux | Procede d'amplification d'arn necessitant une seule etape de manipulation. |
DE4239088A1 (de) * | 1992-11-20 | 1994-05-26 | Solvay Werke Gmbh | Verfahren zur Herstellung einer stabilisierten, wäßrigen Alkalitetrathiocarbonatlösung und deren Verwendung |
AU3279295A (en) * | 1994-10-11 | 1996-05-02 | Entek Corporation | Process for synthesizing thiocarbonates |
CN102502890A (zh) * | 2011-10-17 | 2012-06-20 | 中南大学 | 一种从镍溶液中深度除铜的试剂硫代碳酸镍的合成方法 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2287285A (en) * | 1940-08-30 | 1942-06-23 | Dow Chemical Co | Preparation of potassium thiocarbonate |
US2893835A (en) * | 1955-03-17 | 1959-07-07 | Monsanto Chemicals | Process for preparing thiocarbonates |
US3753918A (en) * | 1970-01-27 | 1973-08-21 | Olin Corp | Solution of alkali metal trithiocarbonate in dimethyl sulfoxide |
ATE155643T1 (de) * | 1983-05-02 | 1997-08-15 | Entek Corp | Verfahren und zusammensetzungen zur räucherung |
-
1990
- 1990-09-27 IL IL9582590A patent/IL95825A/en not_active IP Right Cessation
- 1990-09-30 CN CN90108050.0A patent/CN1052851A/zh active Pending
- 1990-10-01 AU AU65191/90A patent/AU6519190A/en not_active Abandoned
- 1990-10-01 CA CA002067125A patent/CA2067125A1/en not_active Abandoned
- 1990-10-01 WO PCT/US1990/005582 patent/WO1991004944A1/en not_active Application Discontinuation
- 1990-10-01 JP JP2514079A patent/JPH05500498A/ja active Pending
- 1990-10-01 AP APAP/P/1990/000211A patent/AP212A/en active
- 1990-10-01 EP EP90915039A patent/EP0494933A1/en not_active Ceased
- 1990-10-01 PT PT95482A patent/PT95482B/pt not_active IP Right Cessation
- 1990-10-01 MA MA22235A patent/MA21966A1/fr unknown
- 1990-10-01 YU YU184890A patent/YU184890A/sh unknown
- 1990-10-01 HU HU9201097A patent/HUT61250A/hu unknown
- 1990-10-01 BR BR909007699A patent/BR9007699A/pt not_active IP Right Cessation
- 1990-10-02 TR TR90/0951A patent/TR24796A/xx unknown
Non-Patent Citations (1)
Title |
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See references of WO9104944A1 * |
Also Published As
Publication number | Publication date |
---|---|
AP9000211A0 (en) | 1990-10-31 |
HUT61250A (en) | 1992-12-28 |
CA2067125A1 (en) | 1991-04-03 |
TR24796A (tr) | 1992-05-01 |
YU184890A (sh) | 1993-05-28 |
JPH05500498A (ja) | 1993-02-04 |
AU6519190A (en) | 1991-04-28 |
PT95482B (pt) | 1998-08-31 |
IL95825A (en) | 1994-12-29 |
BR9007699A (pt) | 1992-07-21 |
HU9201097D0 (en) | 1992-06-29 |
PT95482A (pt) | 1991-06-25 |
CN1052851A (zh) | 1991-07-10 |
MA21966A1 (fr) | 1991-07-01 |
WO1991004944A1 (en) | 1991-04-18 |
AP212A (en) | 1992-09-06 |
IL95825A0 (en) | 1991-06-30 |
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