70-49-5

Basic information

• Product Name: Mercaptosuccinic acid
• Synonyms: MERCAPTOSUCCINIC ACID;DL-THIOPECTIC ACID;DL-MERCAPTOSUCCINIC ACID;THIOMALIC ACID;2-Thiomalic acid;2-thio-malicaci;2-thiomalicacid;alpha-Mercaptosuccinic acid
• CAS NO: 70-49-5
• Molecular Formula: C₄H₆O₄S
• Molecular Weight: 150.15
• EINECS: 200-736-4
• Product Categories: Building Blocks;Chemical Synthesis;Organic Building Blocks;Sulfur Compounds;Thiols/Mercaptans
• Mol File: 70-49-5.mol
• Article Data: 8

Chemical Properties

• Melting Point: 155-157 °C(lit.)
• Boiling Point: 241.69°C (rough estimate)
• Flash Point: 108.8 °C
• Appearance: White to almost white/Crystalline Powder
• Density: 1.352 (estimate)
• Vapor Pressure: 0.00475mmHg at 25°C
• Refractive Index: 1.5500 (estimate)
• Storage Temp.: 2-8°C
• Solubility: 500g/l
• PKA: pKa 4.68±0.04(H2O t = 20.0±0.05 I = 0.15) (Uncertain)
• Water Solubility: 150 g/L (20 ºC)
• Merck: 14,9343
• BRN: 1099858
• CAS DataBase Reference: Mercaptosuccinic acid(CAS DataBase Reference)
• NIST Chemistry Reference: Mercaptosuccinic acid(70-49-5)
• EPA Substance Registry System: Mercaptosuccinic acid(70-49-5)

Safety Data

• Hazard Codes: Xn,C
• Statements: 22-36/37/38-34-20/21/22
• Safety Statements: 26-36-36/37/39-45-27
• RIDADR: 1759
• WGK Germany: 3
• RTECS: WM8225000
• TSCA: Yes
• HazardClass: 8
• PackingGroup: III
• Hazardous Substances Data: 70-49-5(Hazardous Substances Data)

Usage

Description

Mercaptosuccinic acid is an organic compound characterized by the presence of a thiol (-SH) group and a carboxylic acid (-COOH) group. It is a versatile building block in chemical synthesis and possesses unique properties due to its functional groups, making it suitable for various applications across different industries.

Uses

Used in Pharmaceutical Industry:
Mercaptosuccinic acid is used as an intermediate for the synthesis of active pharmaceutical ingredients. Its ability to form stable complexes with metal ions and its reactivity make it a valuable component in the development of new drugs.
Used in Chemical Synthesis:
Mercaptosuccinic acid is used in the preparation of mercaptosuccinic acid diethyl ester by reaction with ethanol. This ester derivative can be further utilized in various chemical reactions and processes.
Used in Metal Plating Industry:
Mercaptosuccinic acid is used as a brightening agent in metal plating. Its chelating properties allow it to improve the quality and appearance of plated metal surfaces.
Used in Corrosion Inhibition:
Mercaptosuccinic acid serves as an intermediate for the synthesis of corrosion inhibitors. These inhibitors are essential in protecting metal surfaces from degradation and extending the lifespan of various metal components.
Used in Soil Fumigation:
Mercaptosuccinic acid is used in the synthesis of soil fumigants, which are chemicals applied to soil to control pests and improve crop yields.
Used in Nanoparticle Synthesis:
Mercaptosuccinic acid has been used as a dopant for the synthesis of carbon nanodots from citric acid. It can also act as a capping and reducing agent to synthesize monolayer-capped gold nanoparticles, which have potential applications in catalysis, sensing, and biomedical fields.
Used in Antirheumatic Applications:
Mercaptosuccinic acid is utilized in antirheumatic treatments, where it may help alleviate symptoms and improve joint function in individuals suffering from rheumatic conditions.

Purification Methods

Dissolve the acid in water and extract it several times with diethyl ether to remove imprities. The aqueous solution gave the acid on freeze-drying. [Beilstein 3 IV 472.]

InChI:InChI=1/C4H6O4S/c5-3(6)1-2(9)4(7)8/h2,9H,1H2,(H,5,6)(H,7,8)/t2-/m0/s1

Synthetic route

C5H6N2O3S → DL-thiomalic acid (70-49-5)

Conditions	Yield
With ammonium hydroxide In water at 120℃; for 2h; Sealed tube; High pressure;	78%

(2E)-but-2-enedioic acid (110-17-8) → DL-thiomalic acid (70-49-5)

Conditions	Yield
With sodium hydroxide; hydrogen sulfide In water at 120℃; under 7500.75 Torr; for 4h;	75%
With sodium hydroxide; sodium hydrogensulfide
With hydrogen sulfide; molecular sieves 4A (powder) In 1-methyl-pyrrolidin-2-one at 100℃; under 3750.38 Torr; for 5h; Product distribution / selectivity;	72 %Chromat.

2-Acetylsulfanyl-succinic acid bis-((1S,2R,5S)-2-isopropyl-5-methyl-cyclohexyl) ester → DL-thiomalic acid (70-49-5)

Conditions	Yield
With sodium hydroxide at 60℃; for 12h;	68%

maleic anhydride (108-31-6) + O,O-Diethyl hydrogen phosphorodithioate (298-06-6) → DL-thiomalic acid (70-49-5)

Conditions	Yield
beim Erwaermen des Reaktionsprodukts mit Wasser oder wss. Salzsaeure;

bromosuccinic acid (923-06-8, 584-98-5) → DL-thiomalic acid (70-49-5)

Conditions	Yield
With potassium sulphide at 110℃;
With potassium hydroxide; hydrogen sulfide; water nach 5 Tagen versetzt man mit Schwefelsaeure und aethert aus;

ethylcarbamoylsulfanyl-succinic acid (89776-00-1) → DL-thiomalic acid (70-49-5)

Conditions	Yield
With ammonia at 20℃; dextrorotatory form;
in sauerer oder alkalischer Loesung; dextrorotatory form;

ethoxythiocarbonylmercapto-succinic acid (22119-15-9) → DL-thiomalic acid (70-49-5)

Conditions	Yield
With ethanol; ammonia
With ammonium hydroxide
With ammonia levorotatory thiomalic acid;
With ammonia dextrorotatory thiomalic acid;

3,4-dithia-hexane-1,2,5,6-tetracarboxylic acid (3384-95-0) → DL-thiomalic acid (70-49-5)

Conditions	Yield
With sodium hydroxide; aluminium

acetylsulfanyl-succinic acid (6332-90-7) → DL-thiomalic acid (70-49-5)

Conditions	Yield
With sodium hydroxide

maleic acid (110-16-7) → DL-thiomalic acid (70-49-5)

Conditions	Yield
With sodium hydroxide; sodium hydrogensulfide
With hydrogen sulfide; molecular sieves 4A (powder) In 1-methyl-pyrrolidin-2-one at 100℃; under 3900.39 - 3975.4 Torr; for 5h; Product distribution / selectivity;	75 %Chromat.

(carboxymethylthio)succinic acid (99-68-3) → DL-thiomalic acid (70-49-5) + acetic acid (64-19-7)

Conditions	Yield
thymol; potassium nitrate In water Mechanism; examination of further solvents; electrolysis;

(+-)-mercaptosuccinic acid diethyl ester → DL-thiomalic acid (70-49-5)

Conditions	Yield
With sodium hydroxide

dehydropseudothiohydantoinacetic acid → DL-thiomalic acid (70-49-5)

Conditions	Yield
With sodium amalgam

dextrorotatory dimethylcarbaminothiomalic acid → DL-thiomalic acid (70-49-5)

Conditions	Yield
With hydrogenchloride at 20℃; dextrorotatory form;
With sulfuric acid at 20℃; dextrorotatory form;

d lactonemalic acid → DL-thiomalic acid (70-49-5)

Conditions	Yield
With potassium hydrosulfide levorotatory thiomalic acid;

N.N'-diphenyl-pseudothiohydantoin-acetic acid → DL-thiomalic acid (70-49-5)

Conditions	Yield
With barium dihydroxide

potassium salt of/the/ l-bromosuccinic acid → DL-thiomalic acid (70-49-5)

Conditions	Yield
With water; potassium hydrosulfide levorotatory thiomalic acid;
With water; potassium hydrosulfide dextrorotatory thiomalic acid;

potassium salt of/the/ levorotatory bromosuccinic acid → DL-thiomalic acid (70-49-5)

Conditions	Yield
With potassium hydrosulfide dextrorotatory form;
With potassium hydrosulfide levorotatory form;

pseudohydantoinacetic acid → DL-thiomalic acid (70-49-5)

Conditions	Yield
With barium dihydroxide

ethylcarbamoylsulfanyl-succinic acid (89776-00-1) + ammonia (7664-41-7) → DL-thiomalic acid (70-49-5)

Conditions	Yield
dextrorotatory S-ethylaminoformyl-thiomalic acid;

ethylcarbamoylsulfanyl-succinic acid (89776-00-1) + alkali → DL-thiomalic acid (70-49-5)

Conditions	Yield
dextrorotatory S-ethylaminoformyl-thiomalic acid;

(R)-ethoxythiocarbonylmercapto-succinic acid (197433-30-0) + aqueous alcoholic ammonia → DL-thiomalic acid (70-49-5)

Conditions	Yield
at 0℃;

disodium maleate → DL-thiomalic acid (70-49-5) + thiodisuccinic acid (4917-76-4)

Conditions	Yield
With sodium hydrogensulfide; water

hydrogenchloride (7647-01-0) + ethylcarbamoylsulfanyl-succinic acid (89776-00-1) → DL-thiomalic acid (70-49-5) + racemic 3-ethyl-2.4-dioxo-thiazolidin-acetic acid-(5)

Conditions	Yield
dextrorotatory S-ethylaminoformyl-thiomalic acid;

potassium hydrosulfide + (R)-2-hydroxy-succinic acid-4-lactone (177019-47-5) → DL-thiomalic acid (70-49-5)

2-butenedioic acid (6915-18-0) → DL-thiomalic acid (70-49-5)

Conditions	Yield
With ammonium hydroxide; sodium periodate; hydrogen sulfide; acetic acid; cellulose In ethanol at 80℃; under 3750.38 Torr; Michael Addition;

DL-thiomalic acid (70-49-5) → 3,4-dithia-hexane-1,2,5,6-tetracarboxylic acid (3384-95-0)

Conditions	Yield
With 3,6-di(2'-pyridyl)-1,2,4,5-tetrazine In water at 40℃; for 0.05h; Temperature;	99%
With dihydrogen peroxide In ethanol; water at 20℃; for 0.166667h; Catalytic behavior; Solvent; Reagent/catalyst; Green chemistry;	99%
With dihydrogen peroxide In water; ethyl acetate at 20℃; for 0.583333h; Green chemistry;	99%

DL-thiomalic acid (70-49-5) → bis(1,2-dicarboxyethanethio)tellurium(II)

Conditions	Yield
With tellurium oxide; sodium hydroxide	99%

DL-thiomalic acid (70-49-5) + benzylacrylate (2495-35-4) → C14H16O6S

Conditions	Yield
With triethylamine In acetonitrile at 20℃; for 48h;	99%

DL-thiomalic acid (70-49-5) + 4-allylguaiacol (97-53-0) → C14H18O6S

Conditions	Yield
With 2-hydroxy-2-methylpropiophenone In 1,4-dioxane; ethanol at 20℃; for 50h; UV-irradiation;	98%
With benzoin dimethyl ether at 20℃; for 1h; UV-irradiation;

DL-thiomalic acid (70-49-5) → thiodisuccinic acid (4917-76-4)

Conditions	Yield
With dihydrogen peroxide In ethanol; water at 20℃; for 0.0833333h; Solvent; Time; Green chemistry;	98%

DL-thiomalic acid (70-49-5) + PTPBA → C20H20O6S2

Conditions	Yield
With triethylamine In acetonitrile at 50℃; for 0.75h;	97%

DL-thiomalic acid (70-49-5) + 2-Ethylhexyl alcohol (104-76-7) → bis(2-ethylhexyl) mercaptosuccinate (65291-46-5)

Conditions	Yield
With sulfuric acid In benzene for 3h; Heating / reflux;	94.5%

DL-thiomalic acid (70-49-5) + (Et4N)2[MoFe3S4Cl3(tetrachlorocatecholate)] * MeCN → 4(CH3CH2)4N(1+)*[MoFe3S4Cl3(SCH(CH2COOH)COO)]2(4-) = [(CH3CH2)4N]4[MoFe3S4Cl3(SCH(CH2COOH)COO)]2

Conditions	Yield
In acetonitrile absence of air and moisture; slow addn. of stoich. amt. of thiomalic acid to soln. of Mo-complex, stirring for 1 h; filtration, addn. of ether, standing for 5 h, dissoln. of oil in MeCN, pptn. on addn. of ether, filtration, washing (EtOH, Me2CO, ether), drying (vac.); elem. anal.;	94%

DL-thiomalic acid (70-49-5) + p,p'-Bis(benzalhydrazinocarbonylmethylamino)diphenylsulphone (114710-06-4) → p,p'-Bis(5-carboxymethyl-4-oxo-2-phenylthiazolidin-3-ylamidomethylamino)diphenylsulphone (114710-45-1)

Conditions	Yield
at 160℃; for 2h;	93%

DL-thiomalic acid (70-49-5) + thiourea (17356-08-0) + 4-dimethylamino-benzaldehyde (100-10-7) → 2-(4-dimethylaminophenyl)-3-thiocarbamoylthiazolidin-4-one-5-ylacetic acid

Conditions	Yield
With zinc(II) chloride In tetrahydrofuran; ethanol for 10h; Reflux;	93%

DL-thiomalic acid (70-49-5) + phenylhydrazine (100-63-0) + 4-dimethylamino-benzaldehyde (100-10-7) → 2-(4-dimethylaminophenyl)-3-phenylaminothiazolidine-4-one-5ylacetic acid

Conditions	Yield
With zinc(II) chloride In tetrahydrofuran; ethanol for 10h; Reflux;	93%

DL-thiomalic acid (70-49-5) + monovinylheptaisobutylsilsesquioxane (444315-18-8) → C34H72O16SSi8

Conditions	Yield
With 2,2-dimethoxy-2-phenylacetophenone In tetrahydrofuran for 0.166667 - 0.5h; UV-irradiation;	93%
With 2,2'-azobis(isobutyronitrile) In tetrahydrofuran at 60℃; for 10h;	90%

DL-thiomalic acid (70-49-5) + 4-propyl-cyclohexanone (40649-36-3) + adamantane-1-carbohydrazide (17846-15-0) → [4‐(adamantane‐1‐carboxamido)‐3‐oxo‐8‐propyl‐1‐thia‐4‐azaspiro‐[4.5]decan‐2‐yl]acetic acid

Conditions	Yield
Stage #1: 4-propyl-cyclohexanone; adamantane-1-carbohydrazide In toluene at 120℃; for 2h; Dean-Stark; Stage #2: DL-thiomalic acid In toluene at 120℃; Dean-Stark;	93%

DL-thiomalic acid (70-49-5) + (5-chloro-2-neopentylamino-phenyl)-naphthalen-1-yl-methanol (180346-15-0) → (-)-trans-7-chloro-5-(1-naphthyl)-1-neopentyl-2-oxo-1,2,3,5-tetrahydro-4,1-benzothiazepin-3-acetic acid

Conditions	Yield
With propionic acid	92%

DL-thiomalic acid (70-49-5) + C69H136O2Si7 → C101H184O34S8Si7

Conditions	Yield
With 2,2-dimethoxy-2-phenylacetophenone In tetrahydrofuran; methanol for 2h; Inert atmosphere; UV-irradiation;	92%

DL-thiomalic acid (70-49-5) + 5-(3-formyl-4-methoxybenzyl)-2-methoxybenzaldehyde (19782-48-0) + 4-amino-phenol (123-30-8) → 2-[2-(5-3-[5-(carboxymethyl)-3-(4-hydroxyphenyl)-4-oxo-1,3-thiazolan-2-yl]-4-methoxybenzyl-2-methoxyphenyl)-3-(4-hydroxyphenyl)-4-oxo-1,3-thiazolan-5-yl]acetic acid (1050436-10-6)

Conditions	Yield
With zinc(II) chloride In toluene at 110℃; for 0.05h; microwave irradiation;	91%

DL-thiomalic acid (70-49-5) + acetyl chloride (75-36-5) → s-acetylmercaptosuccinic anhydride (6953-60-2)

Conditions	Yield
for 3h; Reflux;	91%

DL-thiomalic acid (70-49-5) + 4-dimethylamino-benzaldehyde (100-10-7) + urea (57-13-6) → 2-(3-carbamoyl-2-(4-(dimethylamino)phenyl)-4-oxothiazolidin-5-yl)acetic acid

Conditions	Yield
With zinc(II) chloride In tetrahydrofuran; ethanol for 10h; Reflux;	91%

DL-thiomalic acid (70-49-5) + 4-dimethylamino-benzaldehyde (100-10-7) + (2,4-dinitro-phenyl)-hydrazine (119-26-6) → 2-(4-dimethylaminophenyl)-3-(2,4-dinitrophenylamino)thiazolidin-4-one-5-ylacetic acid

Conditions	Yield
With zinc(II) chloride In tetrahydrofuran; ethanol for 10h; Reflux;	91%

DL-thiomalic acid (70-49-5) + hematoporphyrin IX dihydrochloride (17696-69-4) → 7,12-bis<1-<(1,2-dicarboxyethyl)thio>ethyl>-3,8,13,17-tetramethyl-21H,23H-porphine-2,18-dipropanoic acid

Conditions	Yield
With L-valine; acetic acid for 0.666667h; Ambient temperature;	90%

DL-thiomalic acid (70-49-5) + 1,6,19,24-Tetraoxa-2,5,20,23-tetraoxocyclohexatriconta-3,21-diene (81847-18-9) → 2-(2,5,20,23-Tetraoxo-1,6,19,24-tetraoxa-cyclohexatriacont-3-ylsulfanyl)-succinic acid (81847-21-4)

Conditions	Yield
	90%

DL-thiomalic acid (70-49-5) + 2-chloro-7-cyclopropyl-4,7-dihydro-3-nitro-4-oxothieno<2,3-b>pyridine-5-carboxylic acid (276693-71-1) → C15H12N2O9S2

Conditions	Yield
With triethylamine In water; acetone at 20℃; for 7h;	90%

DL-thiomalic acid (70-49-5) + N-cyclohexylidene-p-toluidine (36132-68-0) → C17H21NO3S (1133274-41-5)

Conditions	Yield
With zinc(II) chloride at 160℃;	90%

DL-thiomalic acid (70-49-5) + C17H18ClN3O5 + 4-amino-phenol (123-30-8) → 2-(2-((3aR,5S,6S,6aR)-6-((1-(4-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)-3-(4-hydroxyphenyl)-4-oxothiazolidin-5-yl)acetic acid

Conditions	Yield
With zinc(II) chloride In toluene for 0.0666667h; Microwave irradiation;	90%
With zinc(II) chloride In toluene at 110℃; for 0.0666667h; Microwave irradiation;	79%

DL-thiomalic acid (70-49-5) + C37H80O12Si8 → C41H86O16SSi8

Conditions	Yield
With 2,2'-azobis(isobutyronitrile) In tetrahydrofuran at 90℃; for 10h;	90%

DL-thiomalic acid (70-49-5) + C38H82O12Si8 → C42H88O16SSi8

Conditions	Yield
With 2,2'-azobis(isobutyronitrile) In tetrahydrofuran at 90℃; for 10h;	90%

DL-thiomalic acid (70-49-5) + (3aS,4S,6S,6aS)-6-((1-(4-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxole-4-carbaldehyde + 4-amino-phenol (123-30-8) → 2-(2-((3aR,4S,6S,6aS)-6-((1-(4-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)-3-(4-hydroxyphenyl)-4-oxothiazolidin-5-yl)acetic acid

Conditions	Yield
With zinc(II) chloride In toluene at 110℃; for 0.0666667h; Microwave irradiation;	90%

DL-thiomalic acid (70-49-5) + C44H38O12Si8 → C48H44O16SSi8

Conditions	Yield
With 2,2'-azobis(isobutyronitrile) In tetrahydrofuran at 60℃; for 10h;	90%

DL-thiomalic acid (70-49-5) + C44H80O12Si8 (230316-01-5) → C48H86O16SSi8

Conditions	Yield
With 2,2'-azobis(isobutyronitrile) In tetrahydrofuran at 60℃; for 10h;	90%

DL-thiomalic acid (70-49-5) + 7,17-dimethyl-7,17-divinyl-1,3,5,9,11,13,15,1-octaphenylhexacyclo[9.13.11,9 .13,15 .15,13 .111,19 ]decasiloxane → C62H64O22S2Si10

Conditions	Yield
With 2,2'-azobis(isobutyronitrile) In tetrahydrofuran at 60℃; for 10h;	90%

Upstream product

• 108-31-6 maleic anhydride 
• 298-06-6 O,O-Diethyl hydrogen phosphorodithioate 
• 6332-90-7 acetylsulfanyl-succinic acid 
• 110-16-7 maleic acid 
• 110-17-8 (2E)-but-2-enedioic acid 
• 89776-00-1 ethylcarbamoylsulfanyl-succinic acid 
• 7664-41-7 ammonia 
• 197433-30-0 (R)-ethoxythiocarbonylmercapto-succinic acid 
• 7647-01-0 hydrogenchloride 
• 177019-47-5 (R)-2-hydroxy-succinic acid-4-lactone 
• 6915-18-0 2-butenedioic acid 
• 99-68-3 (carboxymethylthio)succinic acid 
• 3384-95-0 3,4-dithia-hexane-1,2,5,6-tetracarboxylic acid 
• 22119-15-9 ethoxythiocarbonylmercapto-succinic acid 

Downstream Products

• 95436-20-7 tritylmercapto-succinic acid 
• 2218-96-4 2,4-dinitrothiophenol 
• 22119-10-4 2-(benzylthio)succinic acid 
• 99-68-3 (carboxymethylthio)succinic acid 
• 4917-76-4 thiodisuccinic acid 
• 88210-83-7 mercapto-succinic acid dibenzyl ester 
• 99974-58-0 cyclohexylmercapto-succinic acid 
• 45015-91-6 (+/-)-propylsulfanyl-succinic acid 
• 110-77-0 2-(ethylsulfanyl)ethanol 
• 7529-08-0 mercaptosuccinic acid dibutyl ester 
• 103939-97-5 [3-(4-Acetylamino-phenyl)-2-(3-nitro-phenyl)-4-oxo-thiazolidin-5-yl]-acetic acid 
• 103912-29-4 [3-(4-Acetylamino-phenyl)-2-(5-bromo-2-hydroxy-phenyl)-4-oxo-thiazolidin-5-yl]-acetic acid 

Relevant articles and documents

Green method for synthesizing high value-added mercaptoacid by catalyzing addition reaction of H2S and olefine acid by using ionic liquid as catalyst

The invention relates to a green method integrating catalysis, reaction and separation, which is used for producing beta-mercapto carboxylic acid through addition of alpha, beta-unsaturated carboxylic acid and H2S by taking amino-functionalized hydrophobic ionic liquid as a catalyst. H2S is activated through tertiary amine alkaline sites contained in the ionic liquid, so that H2S and double bonds of alpha, beta-unsaturated carboxylic acid are subjected to an addition reaction, and recycling of H2S is realized. The product obtained after the reaction can be subjected to water phase liquid-liquid extraction to realize separation of the catalyst and the product, and the ionic liquid can be recycled. In the system, the ionic liquid is both a catalytic medium and a reaction medium, no other organic solvent participates in the system, H2S is efficiently utilized, meanwhile, high-added-value products such as mercapto acid are obtained, and the method is more economical and environmentally friendly and conforms to the development concept of green chemical industry.

Preparation method of beta-sulfhydryl carboxylic acid compound

The invention provides a preparation method of a beta-sulfhydryl carboxylic acid compound. A solid base catalyst used in the method has suitable alkali strength, so that not only is hydrogen sulfide enabled to be activated and a reaction promoted to be carried out, but the binding between carboxyl groups and active sites in raw materials or products is also inhibited, and the active sites are prevented from being deactivated slowly. Furthermore, the solid base catalyst selects a polyhydroxy compound as a carrier, and a great deal of hydroxyl groups on the surface of the carrier can promote thehydrogen sulfide to be dissolved in a reaction system and adsorbed on the surface of the catalyst so as to enable the hydrogen sulfide to be migrated to the positions around the active sites for being activated, so that the high conversion rate and high selectivity of the reaction also can be enabled to be reached at the lower pressure, and the catalytic stability is better. In addition, the preparation method is mild in reaction conditions, and the gas-liquid phase reaction is carried out under the conditions of low temperature and low pressure, so that the method is easily applied to industry. Experiments prove that the reaction conversion rate and selectivity of the beta-sulfhydryl carboxylic acid compound prepared by the method are respectively not less than 98% and 88%. After the compound is continuously evaluated for 100h, the catalytic stability of the compound is proved to be better.

Carbodiimides comprising thiocarbamide acid ester groups

Thiocarbamides comprising at least one carbodiimide group and at least one thiocarbamic ester group of the formula