GB2336584A - Process for the purification of brines - Google Patents
Process for the purification of brines Download PDFInfo
- Publication number
- GB2336584A GB2336584A GB9908550A GB9908550A GB2336584A GB 2336584 A GB2336584 A GB 2336584A GB 9908550 A GB9908550 A GB 9908550A GB 9908550 A GB9908550 A GB 9908550A GB 2336584 A GB2336584 A GB 2336584A
- Authority
- GB
- United Kingdom
- Prior art keywords
- solution
- stage
- process according
- chlorine
- oxidizing agent
- 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.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/14—Purification
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/025—Thermal hydrolysis
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/76—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Process for the purification from organic compounds of an aqueous solution, according to which: (a) the pH of the solution is brought to at least 13; (b) the solution is heated at at least 100‹C for at least 1 hour; (c) at least one chlorine-comprising oxidizing agent is gradually added to the solution. The solution to be purified may contain a sulphonium ion.
Description
2336584 Process for the purification of brines The present invention
relates to a process for the purification from organic compounds of aqueous 5 solutions and in particular of brines.
The aqueous solutions collected as effluents from organic synthesis processes are often laden with troublesome organic compounds, the removal of which is desirable in many cases and very particularly in the case of brines, the exploitation of which by electrolysis in plants equipped with ion-exchange membranes is envisaged, for example for the purpose of producing aqueous sodium hydroxide solutions. This is because several organic compounds seriously affect the performances of the said membranes, in particular the trimethylsulphonium cation ((CH3)3S").
Processes for the removal of organic compounds, for example chlorination processes, are certainly known but these known processes do not make it possible satisfactorily to reduce the content of organic compounds (as measured, for example, by the total organic carbon content, commonly known as "TOW) in the aqueous solutions. In addition, these known processes are ineffective with regard to certain specific organic compounds, for example trimethylsulphonium salts.
Provision has already been made to subject waste water comprising undesired organic substances to an oxidative chemical treatment with heating, the said substances being thus oxidized to carbon dioxide and water. Such a process, disclosed, for example, in the document DE 26 40 603, is generally known under the name of wet oxidation.
The wet oxidation process is comparable with a liquid phase combustion. To achieve satisfactory decomposition of the organic compounds and adequate conversion rates, a predetermined concentration of oxygen as well as high temperatures and high pressures are necessary. This treatment process is therefore very expensive because of its high energy consumption and the expensive equipment used. The temperatures and the - 2 pressures employed can certainly be reduced by the addition of catalysts based on heavy metals but this leads to an additional purification stage in order to remove these catalysts.
The present invention is consequently targeted at providing a process for the purification from organic compounds of aqueous solutions which is simple and efficient, both in terms of the variety of the organic compounds removed and in terms of the final contents of organic compounds in the solutions.
To this end, the present invention relates to a process for the purification from organic compounds of an aqueous solution, according to which:
(a) the pH of the solution is brought to at least 13; (b) the solution is heated at at least 1000C for at least 1 hour; (c) at least one chlorine-comprising oxidizing agent is gradually added to the solution.
This process can take place continuously or batchwise. It is preferable to carry it out batchwise.
This process is advantageously applied to a brine. The term "brine" is understood to denote, conventionally, an aqueous sodium chloride (NaCl) solution in which one or more other constituents can optionally be present in smaller amounts. The process gives good results when it is applied to brines with a sodium chloride content of at least 100 g/1. Their maximum sodium chloride content is that which corresponds to saturation; in practice, content generally does not exceed 300 g/1.
The organic compounds which the process according to the invention is targeted at removing are in particular the compounds of the following types: carboxylic acid (formic acid, acetic acid, and the like), alcohols (methanol, pentanol, aldehydes (acetaldehyde, and the their NaCl and the like), like), amines (alanine, and the like) and in particular sulphur derivatives (dimethyl sulphide, dimethyl sulphoxide, trimethylsulphonium chloride, and the like). The - 3 process gives particularly outstanding results when the solution to be purified comprises at least one sulphonium salt. The term "sulphonium salt" is understood to denote any compound of formula (R1R2R3S)nX, where R,, R2 and R3 are identical or different and denote substituted or unsubstituted alkyl, aryl, aralkyl or alkaryl radicals and X denotes an anion with a valency of n. The X anion is generally a halogen, usually chlorine (n = 1). The invention applies particularly to the case where the sulphonium, salt is trimethylsulphonium chloride. In this case, good results were obtained with trimethylsulphonium chloride contents of the order of 50 to 280 mg/1, without these values, however, having a limiting nature.
In the process according to the invention, the solution to be purified can naturally exhibit a pH value equal to or greater than 13. This, however, is not generally the case and it is then necessary to bring the pH to at least 13 by addition of a strong base or by any equivalent means (for example, by electrochemical means). Use is preferably made of a water-soluble base, for example chosen from alkali metal hydroxides and salts (sodium carbonate, and the like). Alkali metal hydroxides are preferred, in particular sodium hydroxide (NaOH). The amount of strong base to be employed will depend on the solution to be purified, on its initial pH and on the desired pH. Advantageously, the content of strong base in the solution on conclusion of stage (a) is at least 10 mmol per kg of solution, preferably at least 300 mmol/kg.
During the heating stage (b), the temperature of the aqueous solution is advantageously brought to at least 1200C, without, however, exceeding its boiling temperature. Very good results were obtained above 1300C, for example at approximately 1400C. The duration of stage (b) is preferably from 2 to 6 hours. This stage advantageously takes place under autogenous - 4 pressure, in order in particular to prevent the aqueous solution from boiling.
If the aqueous solution comprises a sulphonium, salt, stages (a) and (b) have the effect of decomposing this salt to an alcohol, on the one hand, and to a sulphide, on the other hand. For example, in the case where the solution comprises trimethylsulphonium chloride, stage (b) generally results in the formation of methanol and dimethyl sulphide ( (CH3) 2S).
According to an advantageous alternative form, after stage (b), hydrochloric acid (HCl) is added to the solution. This makes it possible to reduce the amount of chlorine-comprising oxidizing agent used during stage (c). In this alternative form, the amount of hydrochloric acid employed is advantageously such that the pH of the solution is less than 5 or else greater than 9.
The oxidation stage (c) makes it possible to decompose most of the organic compounds still present in the aqueous solution (for example, methanol or dimethyl sulphide, or alternatively an organic acid, such as, for example, formic acid).
The chlorine-comprising oxidizing agent is added to the aqueous solution gradually, so as to prevent the formation of chlorates. To this end, the flow rate of chlorine-comprising oxidizing agent is preferably adjusted so that the total amount of oxidizing agent is introduced over 5 to 30 minutes.
The chlorine-comprising oxidizing agent used in stage (c) is advantageously chosen from chlorine gas (C12) and sodium hypochlorite (NaClO). If a gaseous chlorine -comprising oxidizing agent is used, it can be employed in any conventional way, for example by sparging into the aqueous solution, if appropriate after dilution by means of an inert gas, such as nitrogen.
At the end of stage (c), the solution can equally well be acidic or basic. However, preferably, during stage (c), a sufficient amount of chlorine- 5 comprising oxidizing agent is added to the solution for the pH to become less than 2 and preferably less than 1. The production of a very low pH at the end of the reaction is advantageous in the sense that it results in a very thorough purification, even in the cases where the subsequent use of the purified aqueous solution requires a higher pH, for example in the region of 7 (neutral solution); to this end, use may be made of a conventional technique, for example reaction with a base.
According to an advantageous alternative form, in stage (a), the pH of the solution is brought to at least 13 by addition of an alkaline sodium derivative and the ratio of the number of chlorine atoms in the chlorinecomprising oxidizing agent which are added during stage (c) to the number of sodium atoms which are added during stage (a) is from 0.5 to 1.5.
Stages (a) and (b), on the one hand, and (c), on the other hand, take place in the same reactor or in separate reactors. The reactor or reactors used must be composed of or internally coated with a material exhibiting sufficient mechanical strength and chemical resistance, for example titanium.
Stage (c) can optionally be followed by one or more conventional purification stages, such as a filtration, an additional purification by means of active charcoal or by ozonization, and the like.
Example one kg of brine comprising 270 g/1 of sodium chloride, 60 mg/1 of trimethylsulphonium chloride (TMSC) (that is to say, 19 mg C/1) and 383 mg/1 of formic acid (HCOOH) (i.e., approximately 100 mg C/1), exhibiting an overall TOC of 232 mg C/1, had added to it 300 mmol (12 g) of NaOH and then the brine was heated at 1300C in a stirred autoclave under autogenous pressure (approximately 2.7 bar after 3 hours). After reacting for 3 hours, the TMSC concentration was reduced to 37% of its initial value. Chlorine was subsequently added in a large excess with respect to - 6 the amount of organic compounds (total amount of chlorine: 7.06 g). After 15 minutes, the TOC was reduced to approximately 30 ppm (30 mg of organic carbon per litre), the TMSC concentration being for its part reduced to a value below the threshold for quantification by capillary electrophoresis (< 5 mg/1). The formic acid was virtually completely consumed.
It was found that a gradual addition of chlorine (over approximately 25 minutes) made it possible to obtain a lower final chlorate content than in the case of a rapid addition. The final pH was 13.4 (pH normalized to room temperature).
7 - - 1
Claims (11)
1. Process for the purification from organic compounds of an aqueous solution, according to which:
(a) the pH of the solution is brought to at least 13; (b) the solution is heated at at least 1000C for at least 1 hour; (c) at least one chlorine-comprising oxidizing agent is gradually added to the solution.
2. Process according to Claim 1, in which the aqueous solution is a brine.
3. Process according to either of the preceding claims, in which the solution to be purified comprises at least one sulphonium salt.
4. Process according to one of the preceding claims, in which the pH of the solution is brought to at least 13 by addition of a strong base and the content of strong base in the solution on conclusion of stage (a) is at least 10 mmol per kg of solution.
5. Process according to one of the preceding claims, in which the pH of the solution is brought to at least 13 by addition of sodium hydroxide.
6. Process according to one of the preceding claims, in which the duration of stage (b) is from 2 to 6 hours.
7. Process according to one of the preceding claims, in which, after stage (b), hydrochloric acid (HCl) is added to the solution.
8. Process according to one of the preceding 30 claims, in which the chlorine-comprising oxidizing agent used in stage (c) is chosen from chlorine gas (C12) and sodium hypochlorite (NaClO).
9. Process according to one of the preceding claims, in which, during stage (c), a sufficient amount of chlorine-comprising oxidizing agent is added to the solution for the pH to become less than 2.
10. Process according to one of the preceding claims, in which, in stage (a), the pH of the solution is brought to at least 13 by addition of an alkaline 8 sodium derivative and the ratio of the number of chlorine atoms in the chlorine-compri sing oxidizing agent which are added during stage (c) to the number of sodium atoms which are added during stage (a) is from 0.5 to 1.5.
11. A process for the purification from organic compounds of an aqueous solution as 5 hereinbefore described with reference to the Example.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BE9800297A BE1011880A4 (en) | 1998-04-21 | 1998-04-21 | Method of treatment of brine. |
Publications (2)
Publication Number | Publication Date |
---|---|
GB9908550D0 GB9908550D0 (en) | 1999-06-09 |
GB2336584A true GB2336584A (en) | 1999-10-27 |
Family
ID=3891205
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9908550A Withdrawn GB2336584A (en) | 1998-04-21 | 1999-04-14 | Process for the purification of brines |
Country Status (5)
Country | Link |
---|---|
BE (1) | BE1011880A4 (en) |
BR (1) | BR9901378A (en) |
FR (1) | FR2777558A1 (en) |
GB (1) | GB2336584A (en) |
NL (1) | NL1011815C2 (en) |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7557253B2 (en) | 2005-05-20 | 2009-07-07 | Solvay (Societe Anonyme) | Method for converting polyhydroxylated aliphatic hydrocarbons into chlorohydrins |
EP2085364A1 (en) * | 2008-01-31 | 2009-08-05 | SOLVAY (Société Anonyme) | Process for degrading organic substances in an aqueous composition |
WO2009095429A1 (en) | 2008-01-31 | 2009-08-06 | Solvay (Societe Anonyme) | Process for degrading organic substances in an aqueous composition |
US7939696B2 (en) | 2005-11-08 | 2011-05-10 | Solvay Societe Anonyme | Process for the manufacture of dichloropropanol by chlorination of glycerol |
US8067645B2 (en) | 2005-05-20 | 2011-11-29 | Solvay (Societe Anonyme) | Process for producing a chlorhydrin from a multihydroxylated aliphatic hydrocarbon and/or ester thereof in the presence of metal salts |
US8124814B2 (en) | 2006-06-14 | 2012-02-28 | Solvay (Societe Anonyme) | Crude glycerol-based product, process for its purification and its use in the manufacture of dichloropropanol |
US8197665B2 (en) | 2007-06-12 | 2012-06-12 | Solvay (Societe Anonyme) | Aqueous composition containing a salt, manufacturing process and use |
US8258350B2 (en) | 2007-03-07 | 2012-09-04 | Solvay (Societe Anonyme) | Process for the manufacture of dichloropropanol |
US8273923B2 (en) | 2007-06-01 | 2012-09-25 | Solvay (Societe Anonyme) | Process for manufacturing a chlorohydrin |
US8314205B2 (en) | 2007-12-17 | 2012-11-20 | Solvay (Societe Anonyme) | Glycerol-based product, process for obtaining same and use thereof in the manufacturing of dichloropropanol |
US8378130B2 (en) | 2007-06-12 | 2013-02-19 | Solvay (Societe Anonyme) | Product containing epichlorohydrin, its preparation and its use in various applications |
US8415509B2 (en) | 2003-11-20 | 2013-04-09 | Solvay (Societe Anonyme) | Process for producing dichloropropanol from glycerol, the glycerol coming eventually from the conversion of animal fats in the manufacture of biodiesel |
US8471074B2 (en) | 2007-03-14 | 2013-06-25 | Solvay (Societe Anonyme) | Process for the manufacture of dichloropropanol |
US8507643B2 (en) | 2008-04-03 | 2013-08-13 | Solvay S.A. | Composition comprising glycerol, process for obtaining same and use thereof in the manufacture of dichloropropanol |
US8536381B2 (en) | 2008-09-12 | 2013-09-17 | Solvay Sa | Process for purifying hydrogen chloride |
US8715568B2 (en) | 2007-10-02 | 2014-05-06 | Solvay Sa | Use of compositions containing silicon for improving the corrosion resistance of vessels |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1459284A (en) * | 1974-09-25 | 1976-12-22 | Bp Chem Int Ltd | Effluent treatment |
GB1567767A (en) * | 1975-11-29 | 1980-05-21 | Bayer Ag | Hydrolysis treatment of industrial effluent |
JPH06157007A (en) * | 1992-11-13 | 1994-06-03 | Godo Shigen Sangyo Kk | Method for recovering iodine from waste liquor containing organic iodine compound |
US5445741A (en) * | 1992-12-30 | 1995-08-29 | Solvay Deutschland Gmbh | Process for treating waste water |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5386079A (en) * | 1992-05-19 | 1995-01-31 | Ciba-Geigy Corporation | Wastewater treatment process |
DE4229355A1 (en) * | 1992-09-06 | 1994-03-10 | Solvay Deutschland | Process and appts for the removal of chlorinated organic cpds from effluent - esp. from epichlorohydrin prodn |
-
1998
- 1998-04-21 BE BE9800297A patent/BE1011880A4/en not_active IP Right Cessation
-
1999
- 1999-04-14 GB GB9908550A patent/GB2336584A/en not_active Withdrawn
- 1999-04-15 NL NL1011815A patent/NL1011815C2/en not_active IP Right Cessation
- 1999-04-16 FR FR9904937A patent/FR2777558A1/en not_active Withdrawn
- 1999-04-20 BR BR9901378-9A patent/BR9901378A/en not_active Application Discontinuation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1459284A (en) * | 1974-09-25 | 1976-12-22 | Bp Chem Int Ltd | Effluent treatment |
GB1567767A (en) * | 1975-11-29 | 1980-05-21 | Bayer Ag | Hydrolysis treatment of industrial effluent |
JPH06157007A (en) * | 1992-11-13 | 1994-06-03 | Godo Shigen Sangyo Kk | Method for recovering iodine from waste liquor containing organic iodine compound |
US5445741A (en) * | 1992-12-30 | 1995-08-29 | Solvay Deutschland Gmbh | Process for treating waste water |
Non-Patent Citations (1)
Title |
---|
WPI Abstract Accession No. 94-221535 & JP 6157007 * |
Cited By (30)
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US8415509B2 (en) | 2003-11-20 | 2013-04-09 | Solvay (Societe Anonyme) | Process for producing dichloropropanol from glycerol, the glycerol coming eventually from the conversion of animal fats in the manufacture of biodiesel |
US9663427B2 (en) | 2003-11-20 | 2017-05-30 | Solvay (Société Anonyme) | Process for producing epichlorohydrin |
US7906692B2 (en) | 2005-05-20 | 2011-03-15 | Solvay (Societe Anonyme) | Method for making a chlorohydrin by chlorinating a polyhydroxylated aliphatic hydrocarbon |
US7615670B2 (en) | 2005-05-20 | 2009-11-10 | Solvay (Société Anonyme) | Method for making chlorohydrin in liquid phase in the presence of heavy compounds |
US7893193B2 (en) | 2005-05-20 | 2011-02-22 | Solvay (Société Anonyme) | Method for making a chlorohydrin |
US7906691B2 (en) | 2005-05-20 | 2011-03-15 | Solvay (Societe Anonyme) | Method for making chlorohydrin in corrosion-resistant equipment |
US8344185B2 (en) | 2005-05-20 | 2013-01-01 | SOLVAY (Société Anonyme | Method for making a chlorhydrine by reaction between a polyhydroxylated aliphatic hydrocarbon and a chlorinating agent |
US7557253B2 (en) | 2005-05-20 | 2009-07-07 | Solvay (Societe Anonyme) | Method for converting polyhydroxylated aliphatic hydrocarbons into chlorohydrins |
US8067645B2 (en) | 2005-05-20 | 2011-11-29 | Solvay (Societe Anonyme) | Process for producing a chlorhydrin from a multihydroxylated aliphatic hydrocarbon and/or ester thereof in the presence of metal salts |
US8106245B2 (en) | 2005-05-20 | 2012-01-31 | Solvay (Société Anonyme) | Method for preparing chlorohydrin by converting polyhydroxylated aliphatic hydrocarbons |
US8519198B2 (en) | 2005-05-20 | 2013-08-27 | Solvay (Societe Anonyme) | Method for making an epoxide |
US8420871B2 (en) | 2005-05-20 | 2013-04-16 | Solvay (Societe Anonyme) | Process for producing an organic compound |
US8591766B2 (en) | 2005-05-20 | 2013-11-26 | Solvay (Societe Anonyme) | Continuous process for preparing chlorohydrins |
US8389777B2 (en) | 2005-05-20 | 2013-03-05 | Solvay (Société Anonyme) | Continuous method for making chlorhydrines |
US7939696B2 (en) | 2005-11-08 | 2011-05-10 | Solvay Societe Anonyme | Process for the manufacture of dichloropropanol by chlorination of glycerol |
US8106246B2 (en) | 2005-11-08 | 2012-01-31 | Solvay (Societe Anonyme) | Process for the manufacture of dichloropropanol by chlorination of glycerol |
US8124814B2 (en) | 2006-06-14 | 2012-02-28 | Solvay (Societe Anonyme) | Crude glycerol-based product, process for its purification and its use in the manufacture of dichloropropanol |
US8258350B2 (en) | 2007-03-07 | 2012-09-04 | Solvay (Societe Anonyme) | Process for the manufacture of dichloropropanol |
US8471074B2 (en) | 2007-03-14 | 2013-06-25 | Solvay (Societe Anonyme) | Process for the manufacture of dichloropropanol |
US8273923B2 (en) | 2007-06-01 | 2012-09-25 | Solvay (Societe Anonyme) | Process for manufacturing a chlorohydrin |
US8378130B2 (en) | 2007-06-12 | 2013-02-19 | Solvay (Societe Anonyme) | Product containing epichlorohydrin, its preparation and its use in various applications |
US8399692B2 (en) | 2007-06-12 | 2013-03-19 | Solvay (Societe Anonyme) | Epichlorohydrin, manufacturing process and use |
US8197665B2 (en) | 2007-06-12 | 2012-06-12 | Solvay (Societe Anonyme) | Aqueous composition containing a salt, manufacturing process and use |
US8715568B2 (en) | 2007-10-02 | 2014-05-06 | Solvay Sa | Use of compositions containing silicon for improving the corrosion resistance of vessels |
US8314205B2 (en) | 2007-12-17 | 2012-11-20 | Solvay (Societe Anonyme) | Glycerol-based product, process for obtaining same and use thereof in the manufacturing of dichloropropanol |
WO2009095429A1 (en) | 2008-01-31 | 2009-08-06 | Solvay (Societe Anonyme) | Process for degrading organic substances in an aqueous composition |
US8795536B2 (en) | 2008-01-31 | 2014-08-05 | Solvay (Societe Anonyme) | Process for degrading organic substances in an aqueous composition |
EP2085364A1 (en) * | 2008-01-31 | 2009-08-05 | SOLVAY (Société Anonyme) | Process for degrading organic substances in an aqueous composition |
US8507643B2 (en) | 2008-04-03 | 2013-08-13 | Solvay S.A. | Composition comprising glycerol, process for obtaining same and use thereof in the manufacture of dichloropropanol |
US8536381B2 (en) | 2008-09-12 | 2013-09-17 | Solvay Sa | Process for purifying hydrogen chloride |
Also Published As
Publication number | Publication date |
---|---|
BR9901378A (en) | 2000-04-11 |
BE1011880A4 (en) | 2000-02-01 |
NL1011815C2 (en) | 1999-10-25 |
GB9908550D0 (en) | 1999-06-09 |
FR2777558A1 (en) | 1999-10-22 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |