Methylenebisphosphonic acid
[CAS# 1984-15-2]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Phosphides, metal phosphoric acid, metaphosphoric acid, hypophosphorous acid and pyrophosphate
• Name: Methylenebisphosphonic acid
• Synonyms: Methylenediphosphonic acid
• Molecular Formula: CH₆O₆P₂
• Molecular Weight: 176.00
• CAS Registry Number: 1984-15-2
• EC Number: 217-851-0
• SMILES: C(P(=O)(O)O)P(=O)(O)O

Properties

• Density: 2.1±0.1 g/cm³, Calc.^*
• Melting point: 197-199 ºC (Expl.)
• Index of Refraction: 1.550, Calc.^*
• Boiling Point: 583.2±60.0 ºC (760 mmHg), Calc.^*
• Flash Point: 306.5±32.9 ºC, Calc.^*

Safety Data

• Hazard Symbols: GHS05 Danger
• Hazard Statements: H314
• Precautionary Statements: P260-P264-P280-P301+P330+P331-P302+P361+P354-P304+P340-P305+P354+P338-P316-P321-P363-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Serious eye damage	Eye Dam.	1	H318
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	4	H312
Skin corrosion	Skin Corr.	1C	H314
Specific target organ toxicity - single exposure	STOT SE	3	H335
Substances or mixtures corrosive to metals	Met. Corr.	1	H290

• Transport Information: UN 3261

Discovory and Applicatios

Methylenebisphosphonic acid is an organophosphorus compound that consists of two phosphonic acid groups linked by a methylene bridge. This compound belongs to the family of bisphosphonates, which are known for their wide range of applications in both industrial and pharmaceutical fields. Methylenebisphosphonic acid is of particular interest due to its chemical structure, which allows it to interact effectively with metal ions and its potential to inhibit the deposition of scale-forming minerals.

The discovery of methylenebisphosphonic acid is part of a broader study of phosphonates and bisphosphonates, which began gaining attention in the mid-20th century. The development of bisphosphonates was driven by the need for more effective agents to manage mineral scale formation in various industrial processes, particularly in the oil and gas industry. The compound's structure, with two phosphonic acid groups connected by a methylene bridge, offers unique properties that make it effective as a scale inhibitor and dispersant in aqueous systems. Its ability to form stable complexes with calcium and other metal ions is central to its effectiveness.

The synthesis of methylenebisphosphonic acid typically involves the reaction of phosphorous acid or a phosphorus halide with an alcohol or another suitable precursor. One common method includes the use of a phosphonylation reaction to introduce the two phosphonic acid groups onto a methylene bridge. The reaction is often carried out under controlled conditions to ensure high purity and yield of the final product. Techniques such as chromatography and crystallization are frequently employed to isolate the desired compound from the reaction mixture.

Methylenebisphosphonic acid has several notable applications. One of its primary uses is as a scale inhibitor in water treatment processes. The compound can prevent the formation of mineral scales, such as calcium carbonate or calcium sulfate, in pipes, boilers, and cooling towers. This property is valuable in industries like power generation, oil and gas, and water treatment, where scale formation can lead to costly maintenance and efficiency losses. Methylenebisphosphonic acid is also used in detergents and cleaners to disperse mineral deposits and prevent the buildup of scale on surfaces.

Another significant application of methylenebisphosphonic acid is in the pharmaceutical field, particularly in the development of bisphosphonate drugs. Bisphosphonates, including methylenebisphosphonic acid derivatives, are used to treat bone diseases such as osteoporosis and Paget’s disease. These drugs work by inhibiting bone resorption, which helps to increase bone density and prevent fractures. The compound’s ability to interact with calcium, which is a key component of bone tissue, makes it an ideal candidate for further modification into therapeutic agents.

In conclusion, methylenebisphosphonic acid is a versatile compound with significant applications in both industrial and pharmaceutical fields. Its unique chemical structure, which enables it to act as a scale inhibitor and a precursor for bisphosphonate drugs, underscores its importance in various industries. Ongoing research into its properties and potential applications continues to enhance its value in multiple sectors.