US4418047A - Stable isocyanic acid compositions - Google Patents
Stable isocyanic acid compositions Download PDFInfo
- Publication number
- US4418047A US4418047A US06/304,728 US30472881A US4418047A US 4418047 A US4418047 A US 4418047A US 30472881 A US30472881 A US 30472881A US 4418047 A US4418047 A US 4418047A
- Authority
- US
- United States
- Prior art keywords
- isocyanic acid
- halide
- hydrogen
- labile
- composition according
- 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.)
- Expired - Lifetime
Links
- XLJMAIOERFSOGZ-UHFFFAOYSA-N anhydrous cyanic acid Natural products OC#N XLJMAIOERFSOGZ-UHFFFAOYSA-N 0.000 title claims abstract description 54
- OWIKHYCFFJSOEH-UHFFFAOYSA-N Isocyanic acid Chemical compound N=C=O OWIKHYCFFJSOEH-UHFFFAOYSA-N 0.000 title claims abstract description 53
- 239000000203 mixture Substances 0.000 title claims abstract description 18
- -1 halide compound Chemical class 0.000 claims abstract description 18
- 239000003960 organic solvent Substances 0.000 claims abstract 2
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Natural products CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 11
- 150000004820 halides Chemical class 0.000 claims description 10
- 229910000039 hydrogen halide Inorganic materials 0.000 claims description 10
- 239000012433 hydrogen halide Substances 0.000 claims description 10
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 7
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims description 7
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 claims description 7
- 239000002904 solvent Substances 0.000 claims description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 238000011065 in-situ storage Methods 0.000 claims description 2
- 229910052698 phosphorus Inorganic materials 0.000 claims description 2
- 239000011574 phosphorus Substances 0.000 claims description 2
- 230000003381 solubilizing effect Effects 0.000 claims 1
- 125000003944 tolyl group Chemical group 0.000 claims 1
- CKDWPUIZGOQOOM-UHFFFAOYSA-N Carbamyl chloride Chemical compound NC(Cl)=O CKDWPUIZGOQOOM-UHFFFAOYSA-N 0.000 abstract 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 16
- 229910021529 ammonia Inorganic materials 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 6
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000005829 trimerization reaction Methods 0.000 description 3
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 2
- CPELXLSAUQHCOX-UHFFFAOYSA-N Hydrogen bromide Chemical compound Br CPELXLSAUQHCOX-UHFFFAOYSA-N 0.000 description 2
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 2
- MVPPADPHJFYWMZ-UHFFFAOYSA-N chlorobenzene Chemical compound ClC1=CC=CC=C1 MVPPADPHJFYWMZ-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 150000008282 halocarbons Chemical class 0.000 description 2
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 description 2
- FYSNRJHAOHDILO-UHFFFAOYSA-N thionyl chloride Chemical compound ClS(Cl)=O FYSNRJHAOHDILO-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 238000001321 HNCO Methods 0.000 description 1
- 239000012359 Methanesulfonyl chloride Substances 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000002274 desiccant Substances 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910000042 hydrogen bromide Inorganic materials 0.000 description 1
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 description 1
- 229910000043 hydrogen iodide Inorganic materials 0.000 description 1
- LADVLFVCTCHOAI-UHFFFAOYSA-N isocyanic acid;toluene Chemical compound N=C=O.CC1=CC=CC=C1 LADVLFVCTCHOAI-UHFFFAOYSA-N 0.000 description 1
- ZFSLODLOARCGLH-UHFFFAOYSA-N isocyanuric acid Chemical compound OC1=NC(O)=NC(O)=N1 ZFSLODLOARCGLH-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- QARBMVPHQWIHKH-UHFFFAOYSA-N methanesulfonyl chloride Chemical compound CS(Cl)(=O)=O QARBMVPHQWIHKH-UHFFFAOYSA-N 0.000 description 1
- 239000002808 molecular sieve Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 210000002966 serum Anatomy 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C3/00—Cyanogen; Compounds thereof
- C01C3/14—Cyanic or isocyanic acid; Salts thereof
Definitions
- This invention relates to isocyanic acid, HNCO, and in particular provides stable isocyanic acid compositions which are useful as sources of isocyanic acid for various reactions.
- Isocyanic acid is a particularly troublesome reagent because of its high volatility (b.p., 23.5° C. and tendency to trimerize to form cyanuric acid, a white solid.
- compositions of isocyanic acid in which the isocyanic acid is available for reaction and in which losses of isocyanic acid through volatilization and trimerization and the like are minimized. It is a further object of the invention to provide compositions of isocyanic acid which remain stable for days at a time and which can be stored at room temperature and somewhat higher without significant loss of isocyanic acid content.
- solvents such as aromatics, halogenated hydrocarbons, ethers, aliphatic hydrocarbons and the like, for example, benzene, toluene, chlorobenzene, heptane, tetrahydrofuran, methylene dichloride and the like.
- solvents such as aromatics, halogenated hydrocarbons, ethers, aliphatic hydrocarbons and the like, for example, benzene, toluene, chlorobenzene, heptane, tetrahydrofuran, methylene dichloride and the like.
- solvent is selected because of its compatability with whatever subsequent reactions are intended for the isocyanic acid.
- ethyl ether which forms very stable solutions with isocyanic acid is not usually the solvent of choice because isocyanic acid in ether solutions is difficult to react.
- Aromatic hydrocarbons such as toluene are usually preferred.
- the proportion of isocyanic acid in solution is generally dictated by the eventual use to which the isocyanic acid is to be put. The proportion is also affected by the solubility of isocyanic acid in the particular solvent. Typically, from about 5 to about 30 weight percent isocyanic acid is preferable in the solution.
- the isocyanic acid solution is stabilized by a small amount of labile halide.
- the labile halide is probably present in the composition as carbamoyl halide. It is preferably introduced as hydrogen halide or in the form of halide compound which releases hydrogen halide in situ in the isocyanic acid solution. Such compounds include phosphorus halides, thionyl halides and the like. Carbamoyl halides, of course, can be directly introduced.
- the halide is hydrogen chloride introduced as a gas.
- the amount of labile halide, calculated as the hydrogen halide, which is required to stabilize isocyanic acid solution is less than about 1% by weight based on the isocyanic acid present in the solution. Usually much smaller proportions are all that are required. In most instances less than 0.1% to as low as 0.01% by weight based on the isocyanic acid will suffice.
- the stable isocyanic acid solutions of this invention remain stable, for short periods of time even at temperatures as high as 40° C. This is important particularly when large amounts of isocyanic acid must be raised to and held at elevated temperatures during reactions of isocyanic acid.
- hydrogen halides and compounds that produce hydrogen halides in solutions of isocyanic acid are useful as drying agents to remove water and ammonia from such solutions.
- isocyanic acid for example, by catalytic oxidation of hydrogen cyanide, water is a by-product which is formed along with the isocyanic acid. It is difficult to separate water from the isocyanic acid, and when wet isocyanic acid is dissolved in solvents, such as toluene, the water present goes into solution along with the isocyanic acid.
- water and ammonia can be removed effectively at room temperature by the use of hydrogen halide in molar excess of the amount of water and ammonia present.
- the mechanism by which the water and ammonia are removed is not fully understood but in effect it results in precipitation of insoluble ammonium halide on a mole for mole basis based on the amount of water and the amount of ammonia in solution.
- Examples I and II the bottles were stored at 0° C. and 23° C., respectively, without addition of other components.
- Examples III and IV 185 parts per million of hydrogen chloride (148 mole percent based on the water and ammonia content) were added, and the bottles were stored at 0° C. and 23° C., respectively.
- Examples V and VI approximately 8 weight percent of a molecular sieve (Zeolite) was added, and the bottles were stored at 0° C. and 23° C., respectively. In all six examples samples were withdrawn periodically, and the isocyanic acid content was determined. The data resulting are complied in the annexed Table I.
- isocyanic acid compositions in accordance with this invention is that the isocyanic acid is anhydrous. Even small amounts of water present in isocyanic acid solutions can cause the reactions of isocyanic acid to be sluggish and can reduce the yields of desired products. These effects of water are not exhibited by compositions of this invention because water, if present initially, is removed by the halide as insoluble ammonium halide.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Stable isocyanic acid compositions containing isocyanic acid in an organic solvent therefor, having a small amount of a labile halide compound, such as carbamoyl chloride.
Description
This invention relates to isocyanic acid, HNCO, and in particular provides stable isocyanic acid compositions which are useful as sources of isocyanic acid for various reactions.
Isocyanic acid is a particularly troublesome reagent because of its high volatility (b.p., 23.5° C. and tendency to trimerize to form cyanuric acid, a white solid.
It has been common practice to store isocyanic acid in solution with aromatic and halogenated hydrocarbon solvents to reduce the loss of the compound by evaporation. It has also been common practice to store such solutions at relatively low temperatures, e.g., -20° C. to 0° C. to minimize trimerization. Even in solution at such low temperatures, however, significant losses of isocyanic acid occur both through volatilization and trimerization.
It is accordingly, an important object of this invention to provide stable compositions of isocyanic acid in which the isocyanic acid is available for reaction and in which losses of isocyanic acid through volatilization and trimerization and the like are minimized. It is a further object of the invention to provide compositions of isocyanic acid which remain stable for days at a time and which can be stored at room temperature and somewhat higher without significant loss of isocyanic acid content.
These and other objects of the invention are generally obtained using solutions of isocyanic acid in solvents such as aromatics, halogenated hydrocarbons, ethers, aliphatic hydrocarbons and the like, for example, benzene, toluene, chlorobenzene, heptane, tetrahydrofuran, methylene dichloride and the like. Generally the solvent is selected because of its compatability with whatever subsequent reactions are intended for the isocyanic acid. Thus ethyl ether, which forms very stable solutions with isocyanic acid is not usually the solvent of choice because isocyanic acid in ether solutions is difficult to react. Aromatic hydrocarbons such as toluene are usually preferred.
The proportion of isocyanic acid in solution is generally dictated by the eventual use to which the isocyanic acid is to be put. The proportion is also affected by the solubility of isocyanic acid in the particular solvent. Typically, from about 5 to about 30 weight percent isocyanic acid is preferable in the solution.
In accordance with this invention the isocyanic acid solution is stabilized by a small amount of labile halide. The labile halide is probably present in the composition as carbamoyl halide. It is preferably introduced as hydrogen halide or in the form of halide compound which releases hydrogen halide in situ in the isocyanic acid solution. Such compounds include phosphorus halides, thionyl halides and the like. Carbamoyl halides, of course, can be directly introduced. Preferably the halide is hydrogen chloride introduced as a gas.
Generally the amount of labile halide, calculated as the hydrogen halide, which is required to stabilize isocyanic acid solution is less than about 1% by weight based on the isocyanic acid present in the solution. Usually much smaller proportions are all that are required. In most instances less than 0.1% to as low as 0.01% by weight based on the isocyanic acid will suffice.
The stable isocyanic acid solutions of this invention remain stable, for short periods of time even at temperatures as high as 40° C. This is important particularly when large amounts of isocyanic acid must be raised to and held at elevated temperatures during reactions of isocyanic acid.
As described in our co-pending application, Ser. No. 304,758 filed concurrently herewith, hydrogen halides and compounds that produce hydrogen halides in solutions of isocyanic acid are useful as drying agents to remove water and ammonia from such solutions. In the manufacture of isocyanic acid, for example, by catalytic oxidation of hydrogen cyanide, water is a by-product which is formed along with the isocyanic acid. It is difficult to separate water from the isocyanic acid, and when wet isocyanic acid is dissolved in solvents, such as toluene, the water present goes into solution along with the isocyanic acid.
As described in our co-pending application, water and ammonia (possibly also present) can be removed effectively at room temperature by the use of hydrogen halide in molar excess of the amount of water and ammonia present. The mechanism by which the water and ammonia are removed is not fully understood but in effect it results in precipitation of insoluble ammonium halide on a mole for mole basis based on the amount of water and the amount of ammonia in solution.
In forming stabilized compositions in accordance with the present invention, in order that labile halide be present in the final composition, it is necessary to introduce sufficient hydrogen halide or other source of hydrogen halide to remove any water or ammonia initially present in the isocyanic acid solution, over and above that quantity required to form labile halide required for stability since water and ammonia will preferentially react with the hydrogen halide to remove it from solution in the form of insoluble ammonium halide.
In order to illustrate the practical application of this invention a series of tests were performed comparing stability of varying isocyanic acid compositions. In each case a dry isocyanic acid-toluene solution was prepared containing 15.6 weight percent isocyanic acid. Although nominally dry the isocyanic acid contained a small amount of water and a small amount of ammonium ion in the amounts of 50 parts per million and 11 parts per million, respectively. Samples of the solution were placed in septum covered serum bottles.
In Examples I and II the bottles were stored at 0° C. and 23° C., respectively, without addition of other components.
In Examples III and IV 185 parts per million of hydrogen chloride (148 mole percent based on the water and ammonia content) were added, and the bottles were stored at 0° C. and 23° C., respectively.
In Examples V and VI approximately 8 weight percent of a molecular sieve (Zeolite) was added, and the bottles were stored at 0° C. and 23° C., respectively. In all six examples samples were withdrawn periodically, and the isocyanic acid content was determined. The data resulting are complied in the annexed Table I.
It will be noted that after reaction with the water and ammonia present the amount of labile chloride present in the isocyanic acid solution, calculated as hydrogen chloride, was about 0.04% by weight based on the isocyanic acid, yet the isocyanic acid remained more stable at 23° C., than unstabilized isocyanic acid stored at 0° C.
Results comparable to Examples III and IV are obtained when hydrogen bromide, hydrogen iodide, thionyl chloride and methane sulfonyl chloride are substituted for hydrogen chloride.
An important advantage of isocyanic acid compositions in accordance with this invention is that the isocyanic acid is anhydrous. Even small amounts of water present in isocyanic acid solutions can cause the reactions of isocyanic acid to be sluggish and can reduce the yields of desired products. These effects of water are not exhibited by compositions of this invention because water, if present initially, is removed by the halide as insoluble ammonium halide.
TABLE I
______________________________________
Cyanic Acid,
Example
Additive Time, Days Temp. °C.
wt %
______________________________________
I None 0 0 15.6
1 " 15.0
2 " 14.1
4 " 12.8
6 " 11.9
II None 0.7 23 12.7
1.7 " 8.3
5.0 " 2.9
III HCl 1 0 14.9
2 " 14.8
6 " 15.3
IV HCl 1 23 14.9
1.7 " 14.3
5 " 13.2
V Molecular 1 0 13.5
Sieve 2 " 12.3
4.2 " 10.7
VI Molecular 1 23 11.5
Sieve 4.2 " 4.6
______________________________________
Claims (7)
1. A stable isocyanic acid composition consisting essentially of isocyanic acid, a solubilizing amount of an organic solvent therefor, and a labile halide compound in an amount calculated as hydrogen halide of between 0.01 and 1 weight percent based on the isocyanic acid.
2. A composition according to claim 1 in which the labile halide is the chloride.
3. A composition according to claim 2 in which the labile chloride is introduced as hydrogen chloride.
4. A composition according to claim 1 in which the labile halide is formed by adding a halide compound selected from the group consisting of hydrogen halide and halide compounds which release hydrogen halide in situ.
5. A composition according to claim 1 in which the solvent is toluene.
6. A composition according to claim 1 wherein the labile halide is selected from the group consisting of hydrogen halides, phosphorus halides, thionyl halides and carbamoyl halides.
7. A composition according to claim 1 which is anhydrous.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/304,728 US4418047A (en) | 1981-09-23 | 1981-09-23 | Stable isocyanic acid compositions |
| EP19820105802 EP0075658A1 (en) | 1981-09-23 | 1982-06-30 | Stable isocyanic acid compositions |
| CA000406474A CA1181924A (en) | 1981-09-23 | 1982-07-02 | Stable isocyanic acid compositions |
| JP57162448A JPS5864215A (en) | 1981-09-23 | 1982-09-20 | Stable isocyanic acid composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/304,728 US4418047A (en) | 1981-09-23 | 1981-09-23 | Stable isocyanic acid compositions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US4418047A true US4418047A (en) | 1983-11-29 |
Family
ID=23177724
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US06/304,728 Expired - Lifetime US4418047A (en) | 1981-09-23 | 1981-09-23 | Stable isocyanic acid compositions |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4418047A (en) |
| JP (1) | JPS5864215A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA558780A (en) * | 1958-06-10 | H. Jenkins Leslie | Preparation of isocyanates | |
| NL6516913A (en) * | 1965-12-24 | 1967-06-26 |
-
1981
- 1981-09-23 US US06/304,728 patent/US4418047A/en not_active Expired - Lifetime
-
1982
- 1982-09-20 JP JP57162448A patent/JPS5864215A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA558780A (en) * | 1958-06-10 | H. Jenkins Leslie | Preparation of isocyanates | |
| NL6516913A (en) * | 1965-12-24 | 1967-06-26 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5864215A (en) | 1983-04-16 |
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| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: AMERICAN CYANAMID COMPANY, 1937 WEST MAIN ST., STA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:TRENBEATH, STEVEN L.;NOVAK, ROBERT W.;FELDMAN, ALLAN M.;REEL/FRAME:003925/0335 Effective date: 19810918 |
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