Trimethoxysilane

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

Excerpt from ERG Guide 132 [Flammable Liquids - Corrosive]:

General First Aid:

· Wear positive pressure self-contained breathing apparatus (SCBA).

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

Use dry chemical, aqueous foam, or carbon dioxide. Use water spray to keep fire-exposed containers cool. Fight fire from protected location or maximum possible distance. Approach fire from upwind to avoid hazardous vapors and toxic decomposition products.

If material on fire or involved in fire: Use water in flooding quantities as fog ... Keep run-off water out of sewers and water sources. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible.

Wear special protective clothing and positive pressure self-contained breathing apparatus.

Suitable extinguishing media: For small (incipient) fires, use media such as "alcohol" foam, dry chemical, or carbon dioxide. For large fires, apply water from as far as possible. Use very large quantities (flooding) of water applied as a mist or spray; solid streams of water may be ineffective. Cool all affected containers with flooding quantities of water. ... Use water spray to cool unopened containers.

Special protective equipment for fire-fighters: Wear self contained breathing apparatus for fire fighting if necessary.

Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Moisture sensitive.

Store in a cool, dry, well-ventilated location. Separate from acids, oxidizing materials, and water. Outside or detached storage is preferred.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Releases may require isolation or evacuation. Eliminate all ignition sources. Use water spray to cool and disperse vapors and protect personnel. Control runoff and isolate discharged material for proper disposal.

Personal precautions: Wear respiratory protection. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Remove all sources of ignition. Evacuate personnel to safe areas. Beware of vapors accumulating to form explosive concentrations. Vapors can accumulate in low areas. Methods for cleaning up: Contain spillage, and then collect with non-combustible absorbent material, (e.g. sand, earth, diatomaceous earth, vermiculite) and place in container for disposal according to local / national regulations.

Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains.

Burn in a chemical incinerator equipped with an afterburner and scrubber but exert extra care in igniting as this material is highly flammable. Observe all federal, state, and local environmental regulations. Contact a licensed professional waste disposal service to dispose of this material.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

Caution: silanes are toxic. Avoid contact with skin and eyes. Use effective fume removal device. /Silanes/

If fire becomes uncontrollable or container is exposed to direct flame, consider evacuation of one-third (1/3) mile radius. If material leaking (not on fire), consider evacuation from downwind area based on amount of material spilled, location, and weather conditions.

If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard.

Personnel protection: Keep upwind. Avoid breathing vapors ... Avoid bodily contact with the material.

For more Preventive Measures (Complete) data for Trimethoxy silane (10 total), please visit the HSDB record page.

Excerpt from ERG Guide 132 [Flammable Liquids - Corrosive]:

Immediate precautionary measure

Small spill:

Small spill:

0.50 [ppm]

0.83 [ppm]

2.5 [ppm]

TERRESTRIAL FATE: The hydrolytic half-life of trimethoxysilane is 0.3 minutes at 2 degrees C, pH 7.0 and is estimated to be 3 min in air(1). This tendency to rapidly hydrolyze indicates that other processes effecting the fate of trimethoxysilane in moist or dry soil will not be important(SRC).

AQUATIC FATE: The hydrolytic half-life of trimethoxysilane in water is 0.3 minutes at 2 degrees C, pH 7.0 and 0.2 min at pH 9.0 and pH 4.0(1). This tendency to rapidly hydrolyze indicates that other processes effecting aquatic fate will not be important(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), trimethoxysilane, which has a vapor pressure of 76 mm Hg at 25 °C(2), is expected to exist solely as a gas in the ambient atmosphere. If not immediately hydrolyzed, vapor-phase trimethoxysilane is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 6.4 days(SRC), calculated from its rate constant of 2.5X10-12 cu cm/molecule-sec at 25 °C(SRC), that was derived using a structure estimation method(3). It is estimated that the hydrolysis half life of trimethoxysilane in air is 3 min(4), so hydrolysis will occur faster than any other fate process in air(SRC). Trimethoxysilane does not contain chromophores that absorb at wavelengths >290 nm(5) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc of trimethoxysilane can be estimated to be 220(SRC). According to a classification scheme(2), this estimated Koc value suggests that trimethoxysilane is expected to have moderate mobility in soil; however it is unlikely that it will persist in the environment due to the potential for hydrolysis in the presence of moisture or air. The hydrolytic half-life of trimethoxysilane in water is 0.3 minutes at 2 degrees C, pH 7.0 and therefore, leaching and adsorption to sediment in water will not be an important environmental fate process(SRC).

/SIGNS AND SYMPTOMS/ May be fatal if inhaled. May cause respiratory tract irritation. May be harmful if absorbed through skin. May cause skin irritation. Causes eye irritation.

/SIGNS AND SYMPTOMS/ Severe health hazard. May be fatal if absorbed through skin or inhaled. Corrosive to tissues when wet. Irritating to skin, eyes, and respiratory system.

/SIGNS AND SYMPTOMS/ Vapors ... may be absorbed into corneal tissues causing blindness.

/SIGNS AND SYMPTOMS/ Moderately toxic by inhalation. Mildly toxic by ingestion and skin contact.

For more Human Toxicity Excerpts (Complete) data for Trimethoxy silane (6 total), please visit the HSDB record page.

Trimethoxysilane's production and use as an organic coupling agent(1), adhesive and binding agent, surface activating agent(2), and as an intermediate in the industrial production of organosilanes such as trimethoxysilylpropyl methacrylate(3) may result in its release to the environment through various waste streams(SRC).

The hydrolytic half-life of trimethoxysilane in water is 0.3 minutes at 2 degrees C, pH 7.0(1); therefore, volatilization from water will not be an important environmental fate process(SRC). Trimethoxysilane is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 76 mm Hg(2); however, the rate of hydrolysis in air is estimated to be 0.05 hr (3 min) at 25 °C, pH 7(1).

The rate constant for the gas-phase reaction of trimethoxysilane with photochemically-produced hydroxyl radicals has been estimated as 2.5X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 6.4 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The hydrolytic half-life of trimethoxysilane in water is 0.3 minutes at 2 °C and pH 7.0, and 0.2 minutes at pH 9.0 and pH 4.0. The rate of hydrolysis in air from water vapor is estimated to be 10 times more rapid than in water; 0.05 hr (3 min) at 25 °C, pH 7(2). Trimethoxysilane does not contain chromophores that absorb at wavelengths >290 nm(3) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

Hydrolysis of trimethoxysilane produces 3 moles of methanol and 1 mole of silanetriol. The silane triol produced from hydrolysis can undergo condensation to siloxane oligmers depending on pH and concentration. At high concentrations the condensation can produce highly cross-linked, high molecular weight polymers, but if released slowly the condensation will not occur and will exist predominately as monomer. The polymers are an artifact of hydrolysis and not produced when used as a chemical intermediate in a closed system(1).

Occupational exposure to trimethoxysilane may occur through dermal contact or inhalation of this compound at workplaces where trimethoxysilane is produced or used. Due to the reactive nature of this compound, it is produced and used as site-limited intermediate in closed systems limiting the potential for exposure. Exposure to trimethoxysilane among the general population is not expected due to the rapid hydrolysis when exposed to water in the environment, but limited exposure may be present during the use of commercial products containing this compound(SRC). Final products generally contain less than 0.001 percent trimethoxysilane but may contain up to 0.2 percent(1).

Trimethoxysilane's production and use as an organic coupling agent, adhesive and binding agent, surface activating agent, and as an intermediate in the industrial production of organosilanes such as trimethoxysilylpropyl methacrylate may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 76 mm Hg at 25 °C indicates trimethoxysilane will exist solely in the vapor phase in the atmosphere. Vapor-phase trimethoxysilane will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 6.4 days, however, hydrolysis in air is estimated to occur faster with a half life of 0.05 hours (3 min). Trimethoxysilane does not contain chromophores that absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight. If released to soil, trimethoxysilane is expected to have moderate mobility based upon an estimated Koc of 220; however, it is unlikely to persist in the environment due to the potential for hydrolysis in the presence of moisture in air. Biodegradation, bioconcentration and volatilization are not important fate processes since hydrolysis occurs rapidly. If released into water, trimethoxysilane will hydrolyze rapidly and therefore is not expected to adsorb to suspended solids and sediments. The hydrolytic half-life of trimethoxysilane in water is 0.3 minutes at 2 degrees C, pH 7.0, and 0.2 min at pH 9.0 and pH 4.0. Occupational exposure to trimethoxysilane may occur through dermal contact or inhalation of this compound at workplaces where trimethoxysilane is produced or used. Due to the reactive nature of this compound, it is produced and used as a site-limited intermediate in closed systems, limiting the potential for exposure. Exposure to trimethoxysilane among the general population is not expected due to the rapid hydrolysis when exposed to moisture in the environment; limited exposure may occur during the use of commercial products containing this compound. Final products generally contain less than 0.001 percent trimethoxysilane but may contain up to 0.2 percent. (SRC)