2809-21-4

Basic information

• Product Name: 1-Hydroxyethylidene-1,1-diphosphonic acid
• Synonyms: (1-hydroxyethylene)diphosphonicacid;(1-hydroxyethylidene)bis-phosphonicaci;(1-hydroxyethylidene)di-phosphonicaci;(hydroxyethylidene)diphosphonicacid;1,1,1-ethanetrioldiphosphonate;1000sl;1-hydroxy-1,1-diphosphonoethane;1-Hydroxyethanediphosphonica
• CAS NO: 2809-21-4
• Molecular Formula: C₂H₈O₇P₂
• Molecular Weight: 206.03
• EINECS: 220-552-8
• Product Categories: Industrial/Fine Chemicals;INORGANIC & ORGANIC CHEMICALS;Analytical Chemistry;Ligands for Pharmaceutical Research;Radiopharmaceutical Chemistry (Chelating Reagents);Phosphonate antiscalant;organophosphorus compound;Water treatment
• Mol File: 2809-21-4.mol
• Article Data: 33

Chemical Properties

• Melting Point: 198~199℃
• Boiling Point: 578.8 °C at 760 mmHg
• Flash Point: 303.8 °C
• Appearance: white/Powder
• Density: 1.45 (60% aq.)
• Vapor Pressure: 8.34E-16mmHg at 25°C
• Storage Temp.: Sealed in dry,Room Temperature
• PKA: 1.35, 2.87, 7.03, 11.3(at 25℃)
• Water Solubility: Soluble in water.
• Stability: Stable. Incompatible with strong oxidizing agents.
• Merck: 14,3863
• BRN: 1789291
• CAS DataBase Reference: 1-Hydroxyethylidene-1,1-diphosphonic acid(CAS DataBase Reference)
• NIST Chemistry Reference: 1-Hydroxyethylidene-1,1-diphosphonic acid(2809-21-4)
• EPA Substance Registry System: 1-Hydroxyethylidene-1,1-diphosphonic acid(2809-21-4)

Safety Data

• Hazard Codes: Xi,Xn
• Statements: 37/38-41-22
• Safety Statements: 26-39
• RIDADR: UN 3265
• WGK Germany: 2
• RTECS: SZ8562100
• F: 10
• TSCA: Yes
• HazardClass: 8
• PackingGroup: II
• Hazardous Substances Data: 2809-21-4(Hazardous Substances Data)

Usage

Synthesis

In industry, glacial acetic acid and phosphoryl trichloride are usually used, and then the acylation product and phosphorous trichloride hydrolyzate are condensed. Add the metered amount of water and glacial acetic acid into the reaction kettle and stir evenly. Phosphorus trichloride was added dropwise under cooling, and the reaction temperature was controlled at 40-80°C. The reaction by-product hydrogen chloride gas is condensed and sent to the absorption tower to recover hydrochloric acid. The overflowed acetyl chloride and acetic acid were condensed and returned to the reactor. After dropping phosphorus trichloride, the temperature was raised to 100-130°C, and refluxed for 4-5h. After the reaction, hydrolyzed with steam to evaporate the residual acetic acid and low boilers to obtain 1-Hydroxyethylidene-1,1-diphosphonic acid.

Chemical Properties

light beige powder

Originator

Etidron,Gentili,Italy,1977

Uses

Different sources of media describe the Uses of 2809-21-4 differently. You can refer to the following data:
1. 1-Hydroxyethylidenebis(phosphonic acid) acts as human protein tyrosine phosphatase inhibitor. It is also useful for photographic applications. It finds application to strengthen bone, osteoporosis treatment and to treat Paget's disease of bone. In addition, it is used in corrosion inhibition in circulating cool water systems, oil fields and low-pressure boilers with electric power, the chemical industry, metallurgy and fertilizers. It is also utilized for formulating reverse osmosis and thermal desalination anti-scaling agents. Furthermore, it is used in detergents, water treatment, cosmetics and pharmaceuticals.
2. Etidronate (Didronel) is a human protein tyrosine phosphatase inhibitor with IC50 of 0.2 μM.

Definition

ChEBI: A 1,1-bis(phosphonic acid) that is (ethane-1,1-diyl)bis(phosphonic acid) having a hydroxy substituent at the 1-position. It inhibits the formation, growth, and dissolution of hydroxyapatite crystals by chemisorption to calcium phosphate surfaces.

Manufacturing Process

Phosphorous acid was premixed with acetic acid to form a 50 wt % solution of phosphorous acid dissolved in acetic acid. The acids were mixed on a molar basis of 1.36:1, acetic acid to phosphorous acid, and this corresponded on a mol percentage basis to 57.6% acetic acid and 42.4% phosphorous acid. Acetic anhydride was continuously metered into a stream of the phosphorous acid-acetic acid mixture to form the reaction solution. The acetic anhydride was metered into the acid mixture at a mol ratio of 1.33 mols of acetic anhydride per mol of phosphorous acid. The metering rates were 18.5 lb/hr of the phosphorous acid/acetic acid premixed solution and 15.1 lb/hr acetic anhydride. The reaction solution was continuously passed through a heat exchanger where it was heated to 190°F then it was continuously fed into a two stage back-mix reaction zone where due to the heat of reaction the temperature rose to 275°F. The average residence in the reaction zone was 27 min. The reaction zone consisted of two back-mix reactors each having a capacity of 7.5 pounds of the reaction solution. A stream of reaction solution was continuously with drawn from the second reactor and continuously mixed with a stream of water which was being metered at a rate of 2 lb/hr. This amount of water corresponded to 18% excess over the theoretical amount necessary to hydrolyze all of the acetyl-containing compounds in the reaction solution to free acids. The hydrolyzed solution was continuously passed through a heat exchanger and cooled to room temperature after which the solution was continuously passed to a crystallizer where, with agitation, the ethane-1-hydroxy-1,1-diphosphonic acid crystallized. The slurry was then filtered and the crystals were recovered and dried. Analysis of the product showed a conversion rate of phosphorous acid to ethane-1-hydroxy-1,1- diphosphonic acid of 86%. Sodium hydroxide may be used to give the disodium salt.

Brand name

Didronel (Millot Laboratories, France); Didronel (Procter & Gamble).

Flammability and Explosibility

Notclassified

InChI:InChI=1/C2H8O7P2/c1-2(3,10(4,5)6)11(7,8)9/h3H,1H3,(H2,4,5,6)(H2,7,8,9)/p-4

Synthetic route

(1-hydroxyethylidene)bisphosphonic acid tetramethyl ester (15207-88-2) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
With hydrogenchloride	100%

acetyl chloride (75-36-5) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
Stage #1: acetyl chloride With tris(trimethylsilyl) phosphite at 25℃; Stage #2: In methanol at 25℃; for 1h;	98%
With phosphonic Acid at 120℃;
Stage #1: acetyl chloride With tris(trimethylsilyl) phosphite Cooling with liquid nitrogen; Stage #2: With methanol for 4h;

acetic acid (64-19-7) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
With (1-acetyloxyethylidene)-1,1-bisphosphonic acid In water at 75 - 110℃; for 5h;	97%
With phosphonic Acid; phosphorus trichloride In chlorobenzene at 100℃; for 3h; Inert atmosphere;	87%
With P4O6 heating, other monocarboxylic acids;

phosphorus(III) oxide (12440-00-5) + acetic acid (64-19-7) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
With water at 150℃; under 15001.5 Torr; Concentration; Temperature; Pressure;	97%

C17H48O7P2Si5 → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
With methanol for 1h;	90%

1-acetoxy-4-methylbenzene (140-39-6) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
With hydrogenchloride; P4O6; boron trifluoride 1.) 20 deg C to 25 deg C, 20 h, 2.) 10 h;	68%

1-pentyl acetate (628-63-7) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
With phosphonic Acid; phosphorus trichloride In sulfolane; water 1.) 40 deg C to 60 deg C, 1 h 30 min, 2.) 108 deg C to 113 deg C, 6 h;	39%

acetamide (60-35-5) + ethyl 2-oxocyclohexane carboxylate (1655-07-8) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + 2-amino-2-phosphonocyclohexanecarboxylic acid (102402-46-0) + ammonium 1-aminoethane-1,1-diphosphonate (124589-58-8) + α-amino cyclohexylphosphonic acid (67398-11-2)

Conditions	Yield
Stage #1: acetamide With acetyl chloride In acetic acid for 0.25h; Cooling with ice; Stage #2: ethyl 2-oxocyclohexane carboxylate In acetic acid at 20℃; Cooling with ice; Further stages;	A 4 %Spectr. B 30% C 21 %Spectr. D 18%

1-pentyl acetate (628-63-7) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + (Pentyloxy-phosphono-methyl)-phosphonic acid (104392-46-3)

Conditions	Yield
With hydrogenchloride; P4O6; boron trifluoride 1.) 50 deg C, 4 h, 2.) 6 h;	A 22% B 13%

acetamide (60-35-5) + methyl 2-oxocyclopentane-1-carboxylate (10472-24-9) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + ammonium 1-aminoethane-1,1-diphosphonate (124589-58-8) + α-amino cyclopentylphosphonic acid (67550-64-5) + 2-Amino-2-phosphono-cyclopentanecarboxylic acid (81746-49-8)

Conditions	Yield
Stage #1: acetamide With acetyl chloride In acetic acid for 0.25h; Cooling with ice; Stage #2: methyl 2-oxocyclopentane-1-carboxylate With phosphorus trichloride In acetic acid at 20℃; Cooling with ice; Further stages;	A 4% B 20% C 3 %Spectr. D 64 %Spectr.

(1-Hydroxyethylidene)-1,1-bisphosphonic acid tetraethyl ester (20427-93-4) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
Stage #1: (1-Hydroxyethylidene)-1,1-bisphosphonic acid tetraethyl ester With trimethylsilyl bromide at 0℃; for 1h; Stage #2: With methanol at 0℃;

tetrakis(O-trimethylsilyl)hydroxyethylidenediphosphonic acid (1392687-52-3) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
With ethanol for 0.5h;

formaldehyd (50-00-0) + acetic acid (64-19-7) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + hydroxymethylphosphonic acid (2617-47-2)

Conditions	Yield
Stage #1: formaldehyd; acetic acid at 115℃; for 2h; Stage #2: With phosphorus trichloride at 20℃; for 6h; Reflux; Stage #3: With water for 2.5h; Reflux;

C2H4Cl4O3P2 → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
With water for 2.5h; Reflux;

(1-acetoxyethane-1,1-diyl)bis(phosphonic acid) (7316-54-3) → 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4)

Conditions	Yield
With ethanol at 20 - 125℃; for 1h; Temperature;

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + 2',3'-isopropylidene adenosine (362-75-4) → 2',3'-O-isopropylidenadenosine salt of (1-hydroxyethane-1,1-diyl)bis(phosphonic) acid

Conditions	Yield
In water	99%

ruthenium trichloride hydrate + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + 1,4-diaminobutane (110-60-1) → [NH3(CH2)4NH3][Ru2(1-hydroxyethylidenephosphonateH0.5)2]*2H2O

Conditions	Yield
In water hydrothermal treatment of a mixt. of RuCl3*xH2O, diphosphonic-compound and H2O, adjusted by NH2(CH2)4NH2 to pH - 2.85 at 140°C for 6 days; elem. anal.;	98%

triethanolamine (102-71-6) + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + cobalt(II) nitrate → Co(2+)*HN(C2H4OH)3(1+)*5H(1+)*2CH3C(OH)(PO3)2(4-)*7H2O = [HN(C2H4OH)3][Co(H2O)2H5(CH3C(OH)(PO3)2)2]*5H2O

Conditions	Yield
With glacial acetic acid In water several d; decantation, washing (aq. HOAc), filtration, drying in air at room temp.; elem. anal.;	98%
In water slow evapn., filtration, drying in air at room temp.; elem. anal.;	93%

triethanolamine (102-71-6) + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + nickel(II) nitrate → Ni(2+)*HN(C2H4OH)3(1+)*5H(1+)*2CH3C(OH)(PO3)2(4-)*7H2O = [HN(C2H4OH)3][Ni(H2O)2H5(CH3C(OH)(PO3)2)2]*5H2O

Conditions	Yield
In water slow evapn., filtration, drying in air at room temp.; elem. anal.;	97%
With glacial acetic acid In water several d; decantation, washing (aq. HOAc), filtration, drying in air at room temp.; elem. anal.;	97%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + C52H76N4O8 (134868-25-0) → C52H76N4O8*4C2H8O7P2

Conditions	Yield
In water for 12h;	97%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + C68H108N4O8 → C68H108N4O8*4C2H8O7P2

Conditions	Yield
In water for 12h;	97%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) → barium dihydrogen 1-hydroxyethane-1,1-diphosphonate dihydrate

Conditions	Yield
With barium(II) chloride In potassium hydroxide for 120h;	96%

zinc(II) nitrate (10196-18-6) + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) → Zn2(PO3)2C(OH)CH3*5H2O

Conditions	Yield
With sodium hydroxide In water components mixing (molar ratio Zn:org. acid=1:2), aq. NaOH addn. (molar ratio NaOH:org. acid=3.5-4.5), mixt. stirring continuously for 14 d, pptn.; ppt. thoroughly pressing free from mother liquor, washing (alcohol), drying at room temp.; elem. anal.; thermogravimetric anal.;	96%

terbium(III) chloride hexahydrate + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + ethane-1-hydroxy-1,1-diphosphonic acid tetrasodium salt (2666-14-0, 3794-83-0, 7414-83-7, 13529-88-9, 13710-39-9, 17721-68-5, 29329-71-3, 32573-98-1) → [Tb(etidronic acid(-3H))(H2O)]*3H2O

Conditions	Yield
With GeO2 In water High Pressure; stirred at ambient temp., heated at 150°C; washed (H2O), filtered, air-dried at room temp.; elem. anal.;	96%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + C56H84N4O8 (683207-66-1) → C56H84N4O8*4C2H8O7P2

Conditions	Yield
In water for 12h;	96%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + 4,6,10,12,16,18,22,24-octahydroxy-5,11,17,19-tetrakis(dimethylaminomethyl)-2,8,14,20-tetramethylpentacyclo[19.3.1.13,7.19,13.115,19]octacosa-1(25),3,5,7(28),9,11,13(27),15,17,19(26),21,23-dodecaene (134887-74-4) → C44H60N4O8*4C2H8O7P2

Conditions	Yield
In water for 12h;	96%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + N,N-dimethyl-formamide (68-12-2, 33513-42-7) + calcium hydroxide → (dimethylammonium)2[Ca(1-hydroxyethylidene-1,1-diphosphonic acid-2H)2]

Conditions	Yield
In ethanol; water at 160℃; for 72h; pH=3.01; High pressure;	93.7%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + polyhexamethyleneguanidinium hydrochloride → polyhexamethyleneguanidinium 1-hydroxyethylidenediphosphonate, product from metacide and xydiphone (feed ratio 1:5.0)

Conditions	Yield
In various solvent(s)	92%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + erbium(III) chloride hexahydrate + water (7732-18-5) → [Er8(H2O)4(etidronic acid(-4H))6]n

Conditions	Yield
at 150 - 230℃; for 72h; pH=1-2;	92%

yttrium(III) chloride hexahydrate + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + ethane-1-hydroxy-1,1-diphosphonic acid tetrasodium salt (2666-14-0, 3794-83-0, 7414-83-7, 13529-88-9, 13710-39-9, 17721-68-5, 29329-71-3, 32573-98-1) → [Y(etidronic acid(-3H))(H2O)]*3H2O

Conditions	Yield
With GeO2 In water High Pressure; stirred for 0.5 h at ambient temp., heated at 150°C for 3 d; washed (H2O), filtered, air-dried at room temp.; elem. anal.;	91%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + polyhexamethyleneguanidinium hydrochloride → polyhexamethyleneguanidinium 1-hydroxyethylidenediphosphonate, product from metacide and xydiphone (feed ratio 1:4.0)

Conditions	Yield
In various solvent(s)	89%

cobalt(II) chloride hexahydrate + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + 1,4-diaminobutane (110-60-1) → [NH3(CH2)4NH3]Co2(hedpH)2*2H2O

Conditions	Yield
In water High Pressure; mixt. CoCl2*6H2O, 50% hedpH4, and H2O adjusted with 1,4-butylenediamine to pH 4.83 was treated hydrothermally at 140°C for 45 h; elem. anal.;	89%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + urea (57-13-6) → C2H8O7P2*2CH4N2O

Conditions	Yield
In water at 90℃; for 2h;	89%

1,6-Hexanediamine (124-09-4) + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + guanidine hydrogen carbonate (124-46-9, 20734-13-8, 100224-74-6, 593-85-1) → C141H305N63*21C2H8O7P2

Conditions	Yield
Stage #1: 1,6-Hexanediamine; guanidine hydrogen carbonate In 1,3,5-trimethyl-benzene at 165℃; for 8h; Stage #2: 1-hydroxyethylene-(1,1-diphosphonic acid)	88%

ytterbium(III) chloride hexahydrate + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + ethane-1-hydroxy-1,1-diphosphonic acid tetrasodium salt (2666-14-0, 3794-83-0, 7414-83-7, 13529-88-9, 13710-39-9, 17721-68-5, 29329-71-3, 32573-98-1) → [Yb(etidronic acid(-3H))]*H2O

Conditions	Yield
In water High Pressure; stirred at ambient temp. for 0.5 h, heated at 150°C for 3 d; washed (H2O), filtered, air-dried at room temp.; elem. anal.;	88%

Allyl glycidyl ether (106-92-3) + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) → C8H14O9P2(4-)*4Na(1+)

Conditions	Yield
With sodium hydroxide In water at 80 - 95℃;	88%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + ammonium molybdate tetrahydrate + ammonia (7664-41-7) → hexaammonium bis(1-oxyethylidenediphosphonate)dioxomolybdenum tetrahydrate

Conditions	Yield
In water at 20℃; for 48h; pH=8 - 9;	88%

manganese(II) chloride tetrahydrate + 1,5-diaminopentane (462-94-2) + 1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) → [NH3(CH2)5NH3][Mn2(hedpH)2]*2H2O

Conditions	Yield
With NaF In water mixt. MnCl2*4H2O, hedpH4, NaF, and water was adjusted to pH 4 with 1,5-diaminopentane and kept in autoclave at 110°C for 2 d; react. mixt. was cooled to room temp.; elem. anal.;	87%

1-hydroxyethylene-(1,1-diphosphonic acid) (2809-21-4) + 1,1,1,3,3,3-hexamethyl-disilazane (999-97-3) → tetrakis(O-trimethylsilyl)hydroxyethylidenediphosphonic acid (1392687-52-3)

Conditions	Yield
at 25 - 140℃;	87%

Upstream product

• 75-36-5 acetyl chloride 
• 20427-93-4 (1-Hydroxyethylidene)-1,1-bisphosphonic acid tetraethyl ester 
• 7316-54-3 (1-acetyloxyethylidene)-1,1-bisphosphonic acid 
• 12440-00-5 phosphorus(III) oxide 
• 64-19-7 acetic acid 
• 50-00-0 formaldehyd 
• 1392687-52-3 tetrakis(O-trimethylsilyl)hydroxyethylidenediphosphonic acid 
• 60-35-5 acetamide 
• 1655-07-8 ethyl 2-oxocyclohexane carboxylate 
• 10472-24-9 methyl 2-oxocyclopentane-1-carboxylate 
• 15207-88-2 (1-hydroxyethylidene)bisphosphonic acid tetramethyl ester 
• 140-39-6 1-acetoxy-4-methylbenzene 
• 628-63-7 1-pentyl acetate 

Downstream Products

• 2666-14-0 etidronate disodium 
• 42220-47-3 tris(2-hydroxyethanaminium) (1-hydroxyethylidene)diphosphonate 

Relevant articles and documents

Synthesis of 1-hydroxymethylene-1,1-bis(phosphonic acids) from acid anhydrides: Preparation of a new cyclic 1-acyloxymethylene-1,1-bis(phosphonic acid)

In continuing with our work to find new pathways to bis(phosphonate) structures we report on their synthesis from tris(trimethylsilyl) phosphite and acid anhydride. This new synthesis allows a direct access to a 1-hydroxymethylene-1,1-bis(phosphonic acid) functionalised by a carboxylic function on the side chain. Moreover, we describe the formation of an original cyclic bis(phosphonate) obtained from phthalic anhydride. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Strategies for the preparation of (1-acetyloxyethylidene)-1,1-bisphosphonic acid derivatives

The novel strategies for the synthesis of acetylated etidronic acid derivatives were investigated. (1-Acetyloxyethylidene)-1,1-bisphosphonic acid and its P,P′-dimethyl, trimethyl and tetramethyl esters were prepared in high 81-100% yields.

Method for preparing hydroxyalkylene diphosphonic acid from yellow phosphorus

The invention relates to the technical field of scale inhibitors, in particular to a preparation method of hydroxyalkylene diphosphonic acid. The preparation method comprises the following steps: insufficiently burning yellow phosphorus in oxygen to obtain phosphorus trioxide, and then making the phosphorus trioxide react with fatty acid and water to obtain hydroxyalkylene diphosphonic acid. The method has the advantages of fewer raw materials and simple steps, thereby saving the reaction time and lowering the energy consumption. A large amount of hydrogen chloride gas is not generated in thereaction process, and a hydroxyalkylene diphosphonic acid product with high yield and good quality can be obtained.

"water soluble" palladium nanoparticle engineering for C-C coupling, reduction and cyclization catalysis

The use of Pd nanoparticles (Pd-NPs) to realize several important organic reactions allows efficient catalysis with low metal loading (1000 ppm), hence providing a greener catalytic system. However, to be truly green Pd-NPs need to be synthesized in a sustainable manner and be able to react in aqueous media in order to avoid the use of organic solvents. Here we describe an original and eco-friendly synthesis of Pd-NPs (using benign reactants and simple conditions) perfectly stable in water. Remarkably, this synthesis allows for control over their size and morphology by simply tuning the pH of the stabilizer. We then evaluate the catalytic efficiency of these Pd-NPs on six different model reactions (Suzuki Miyaura, Sonogashira, Heck, nitrophenol reduction and pentynoic cycloisomerization) in aqueous media. We show that the stabilizer structure influences the activity owing to its ability to promote the mass transfer of the organic substrates towards the NP surface in the aqueous environment. Finally, catalytic evaluations show that our nano-catalysts prepared in an eco-friendly manner are among the best catalysts described so far in the literature in each case, with high turnover frequencies reached with a low loading of palladium.

Copolymers having gem-bisphosphonate groupings

A copolymer includes a main hydrocarbon chain and side groups including carboxylic groups and polyoxyalkylate groups. The copolymer further includes gem-bisphosphonate groups. A composition, such as n admixture for suspensions of mineral particles, includes the copolymer. The copolymer can be used for fluidifying suspensions of mineral particles and maintaining the fluidity of such suspensions. The copolymer can also be used for reducing the sensitivity of hydraulic compositions to clays and alkaline sulfates.

1-hydroxyethylidene-1,1-diphosphonic acid and ethyl acetate coproduction process

The invention discloses a 1-hydroxyethylidene-1,1-diphosphonic acid and ethyl acetate coproduction process. The coproduction process is completed by taking phosphorus trichloride, glacial acetic acid, deionized water and ethyl alcohol according to steps as shown in the specification. By replacement of deionized water with ethyl alcohol as an esterlysis agent, a great quantity of acetic acid can be generated after alcoholysis of esters into HEDP (1-hydroxyethylidene-1,1-diphosphonic acid), ethyl acetate is quickly generated by ethyl acetate and acetic acid under acceleration of strong organic acid HEDP. Due to simultaneity and mutual promotion of two reactions, reaction rate is increased while waste recycling is realized, economic benefits are increased, wastewater quantity is decreased, and indexes of prepared HEDP coproduced ethyl acetate products accord with indexes of industrial products.

Hydroxyethylidene diphosphonic acid production process for the concentration of the low-concentration acetic acid

The invention provides a low-concentration acetic acid concentrating process for a hydroxyl ethylidene diphosphonic acid production process. The process provided by the invention has the advantages that the process is a continuous concentrating process and the concentration of finally-collected acetic acid is higher than 99%. The process is characterized by being implemented by a mixing kettle, a reactor, a gas-liquid separator and more than three hydrolysis reactors. According to the process, a process flow is shown in a drawing, a liquid intermediate product, i.e. hydroxyl ethylidene diphosphonic acetate, obtained through the gas-liquid separator is sequentially and cyclically filled in the hydrolysis reactors of one to n, the sequential hydrolysis and discharging are carried out, and an obtained acetic acid solution sequentially enters a next hydrolysis reactor and participates in hydrolysis, so that the continuous increase of the concentration and the comprehensive utilization of heat energy are realized.

A high-purity arsenic of the process for the preparation of hydroxy ethylidene diphosphonic acid

The invention relates to a preparation process for high-purity low-arsenic hydroxyethylidene diphosphonic acid. The preparation process comprises the following steps: with phosphorus trichloride, acetic acid and ammonium thioacetate as raw materials, controlling process conditions at first, reacting acetic acid with phosphorus trichloride in a reaction vessel to produce hydroxyethylidene diphosphonic acid and adding ammonium thioacetate in the process of the reaction; and then subjecting an obtained material to concentration and air flushing to remove impurities, adding ammonium thioacetate and carrying out arsenic removal and centrifugation so as to obtain the high-purity low-arsenic hydroxyethylidene diphosphonic acid. According to the invention, scientific technology is employed for product purification, no other substance like a crystal nucleus and a crystallization promoter is added, so no new impurity is introduced. Hydroxyethylidene diphosphonic acid in the high-purity low-arsenic hydroxyethylidene diphosphonic acid prepared in the invention is more than 95%, and arsenic content in the high-purity low-arsenic hydroxyethylidene diphosphonic acid is less than 2 ppm; the preparation process overcomes problems in packaging, transporting and on-site application of liquid hydroxyethylidene diphosphonic acid and broadens the application fields of the high-purity low-arsenic hydroxyethylidene diphosphonic acid.

METHOD FOR THE SYNTHESIS OF ETHANE-1-HYDROXY-1,1-DIPHOSPHONIC ACID

The present invention is related toa method for the synthesis of ethane-1-hydroxy-1,1-diphosphonic acid or its salt which includes the steps of reacting tetraphosphorus hexaoxideand acetic acid under controlled reaction conditions; hydrolyzing the formed ethane-1-hydroxy-1,1-diphosphonic acid condensates to form ethane-1-hydroxy-1,1-diphosphonic acid; further processing the ethane-1-hydroxy-1,1-diphosphonic acid solution. The process according to the method of the present invention is highly controllable and further is characterized by a high selectivity.

Microwave-assisted efficient synthesis of bisphosphonate libraries: A useful procedure for the preparation of bisphosphonates containing nitrogen and sulfur

Microwave-assisted rapid and efficient procedure for the synthesis of bisphosphonate and their libraries is described in solvent-free medium. Bisphosphonates having nitrogen and sulfur are synthesized following this new procedure. This procedure is simple and can be useful for the generation of compound libraries of a class of bone-resorptive inhibitors such as N- and N-, S- containing bisphosphonates.