GB640976A - Improvements in the manufacture of thiourea - Google Patents
Improvements in the manufacture of thioureaInfo
- Publication number
- GB640976A GB640976A GB9269/48A GB926948A GB640976A GB 640976 A GB640976 A GB 640976A GB 9269/48 A GB9269/48 A GB 9269/48A GB 926948 A GB926948 A GB 926948A GB 640976 A GB640976 A GB 640976A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sulphide
- thiourea
- cyanamide
- reaction
- mother liquor
- 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
Links
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Thiourea is prepared by progressively introducing free cyanamide, i.e. in the crystalline or fused state, into an aqueous solution of alkali sulphide which is maintained saturated with hydrogen sulphide. The excess hydrogen sulphide prevents side reactions by converting any base formed into the corresponding sulphide and is maintained by passing a current of the gas through the reaction vessel during operation. Temperatures instanced are 30-60 DEG C., particularly 50 DEG C. Thiourea may be isolated by crystallization from the reaction medium and the mother liquor returned for further processing. In examples: (1) molten cyanamide at 45 DEG C., and (2) crystallized cyanamide is fed into a closed vessel containing aqueous ammonia maintained saturated with hydrogen sulphide at 45-50 DEG C. and when reaction is complete the mixture is cooled to 15 DEG C., crystals of thiourea collected and mother liquor continuously recycled, in (3) sodium sulphide is prepared and used in place of the ammonium sulphide of (1), and in (4) a continuous process is described in which molten cyanamide is run into aqueous ammonium sulphide saturated at 20 DEG C. with thiourea and after reaction at 45 DEG C. the mixture is passed to a cooling vessel at 20 DEG C., the precipitated thiourea filtered off and the mother liquor recycled. Specifications 634,463 and 636,600 are referred to.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR640976X | 1947-04-02 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB640976A true GB640976A (en) | 1950-08-02 |
Family
ID=8997822
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9269/48A Expired GB640976A (en) | 1947-04-02 | 1948-04-01 | Improvements in the manufacture of thiourea |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB640976A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102731356A (en) * | 2011-04-15 | 2012-10-17 | 中国石油化工股份有限公司 | Thiourea cleaning production method |
CN118079823A (en) * | 2024-04-18 | 2024-05-28 | 东营新航新材料科技有限公司 | Thiourea synthesis system and method for preparing thiourea |
-
1948
- 1948-04-01 GB GB9269/48A patent/GB640976A/en not_active Expired
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102731356A (en) * | 2011-04-15 | 2012-10-17 | 中国石油化工股份有限公司 | Thiourea cleaning production method |
CN118079823A (en) * | 2024-04-18 | 2024-05-28 | 东营新航新材料科技有限公司 | Thiourea synthesis system and method for preparing thiourea |
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