化工社化工社 化学情報印刷レポート · 研究参考用
Silica
無定型石英(シリカゲル) · 二酸化ケイ素 · 含水二酸化ケイ素 · 非晶質シリカ (シリカゲル、沈降シリカ) · シリカゲル PS DRYING AGENT WITH INDICATOR · シリカゲル RUBIN COBALT FREE,WITH MOISTURE INDICATOR,DRYING AGENT · シリカゲル.白色 5-20MESH 中粒 · シリカゲル.白色 6MESH UP 大粒
識別子と物理属性
| CAS No. | 112926-00-8 |
|---|---|
| 分子式 | O2Si |
| 平均分子量 | 60.084 g/mol |
| 単同位体質量 | 59.96675577 g/mol |
| SMILES | O=[Si]=O |
| InChIKey | VYPSYNLAJGMNEJ-UHFFFAOYSA-N |
| PubChem CID | 24261 |
| ChEMBL | CHEMBL2108563 |
| ChEBI | CHEBI:30563 |
| EC No. | 231-545-4 |
| DTXSID | DTXSID1029677 |
| 現地名 | シリカゲル |
化学・物理的性質
| 極性表面積 | 34.1 |
|---|---|
| 水素結合供与体数 | 0 |
| 水素結合受容体数 | 2 |
| 回転可能結合数 | 0 |
| 重原子数 | 3 |
| 形式電荷 | 0 |
| 複雑度 | 18.3 |
| 物質分類 | Mineral Dusts -> Other Mineral DustsMajor ion |
| 医薬品 | Pharmaceuticals -> Used in Switzerland |
| 化粧品 | Cosmetics ingredient -> Anticaking/AbsorbentsBaseBulking/ViscosityColorantConditioning/EmollientEmulsifierMoisturizing/HumectantOpacifying AgentOther (Specify)Preservative/StabilizerSolventCosmetic ingredients (Silica) -> CIR (Cosmetic Ingredient Review)AbrasiveViscosity controlling |
| SpringerMaterials Properties | electron density of states |
| 香料 | Fragrance Ingredient (Silica) -> IFRA transparency List |
| 農薬 | RepellantsActive substance -> EU Pesticides database: Approved |
| 臭い | Odorless無臭 |
| 味 | Tasteless |
| 食品添加物 | ANTICAKING AGENT OR FREE-FLOW AGENT, ANTIOXIDANT, COLOR OR COLORING ADJUNCT, DRYING AGENT, EMULSIFIER OR EMULSIFIER SALT, FLAVORING AGENT OR ADJUVANT, FORMULATION AID, HUMECTANT, LUBRICANT OR RELEASE AGENT, -> FDA Substance added to food |
| 密度 | 2.2 (NIOSH, 2024) - Denser than waterwill sink2.2 @ 25 °C2.6Colorless crystals or white powderodorless and tastelessdensity: 2.2-2.6soluble in molten alkai when finely divided and amorphous /Silicon dioxide/Density = 2.20 g/cmRefractive index = 1.459Surface tension = 5.200 @ 298 K (calc)Thermal conductivity = 1.37 W/m-deg K at 298 deg KHeat of Formation = -903.2 kJ/mol at 298 deg KHeat Capacity = 37.94 J/mol-deg K at 298 deg KDielectric Constant = 3.8 /Corning 7940 fused silica/Density = 2.648 /alpha-Quartz/ /from table/ |
| Color/Form | Amorphous powderTransparent to gray powder (Note: Amorphous silica is the non-crystalline form of O2Si). ... solidSilica gel is a coherent, rigid, continuous three-dimensional network of spherical particles of colloidal microporous silica.Transparent crystals |
| 溶解度 | Insoluble (NIOSH, 2024)The solubility of the various phases of silicas is very complex and depends upon several factors. Solubility increases with temperature and pH and is affected by the presence of trace metals. Particle size influences the rate of solubility. /Silica/Silica is rather poorly soluble in water although solubility is higher for the amorphous than for the crystalline morphologies. ... The external amorphous layer in quartz is more soluble than the crystalline underlying core.AMORPHOUS IS SOL IN ALKALIES, ESP WHEN FINELY DIVIDEDPractically insoluble in water or acids. Dissolves readily in HF, forming silicon tetrafluoride.水に不溶 |
| 融点 | 1610°C |
| 沸点 | 2230℃ |
| 引火点 | 23°C |
| 貯蔵条件 | 2-8°C |
| 外観・状態 | 粉末または顆粒 |
| 比重 | 0.88g/ml |
| 色 | 青い |
| pH | ~6.8 (10% in aq. suspension) |
| Merck | 14,8493 |
| 化粧品成分の機能 | 不透明剤吸収性研磨剤粘度制御固結防止増量剤 |
| CAS データベース | 112926-00-8 |
| EPAの化学物質情報 | Silica gel, pptd., cryst.-free (112926-00-8) |
化学的特性
white to off-white powder
安全性と法規制
| GHS 分類 | Not ClassifiedAggregated GHS information provided per 9127 reports by companies from 60 notifications to the ECHA C&L Inventory.This chemical does not meet GHS hazard criteria for 35% (889 of 2540) of reports.WarningH315 (56.3%): Causes skin irritation [Warning Skin corrosion/irritation]P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement) |
|---|---|
| 規制情報 | Chemical: SilicaChemical: Cristobalite (SiO2)Chemical: Silica, vitreousChemical: Calcined diatomiteRegulation (EC) No 257/2010Commission Regulation (EC) No 2229/2004 |
| その他の安全情報 | IMAP assessments - Cristobalite (SiO2): Environment tier I assessmentIMAP assessments - Calcined diatomite: Environment tier I assessmentIMAP assessments - Silica, vitreous: Human health tier I assessmentIMAP assessments - Silica: Environment tier I assessment |
| 火災危険 | Not combustible. |
| 健康有害性 | Excerpt from NIOSH Pocket Guide for Silica, amorphous: |
| 有害性の概要 | Silica is another name for the chemical compound composed of silicon and oxygen with the chemical formula SiO2, or silicon dioxide. There are many forms of silica. All silica forms are identical in chemical composition, but have different atom arrangements. Silica compounds can be divided into two groups, crystalline (or c-silica) and amorphous silica (a-silica or non-crystalline silica). c-Silica compounds have structures with repeating patterns of silicon and oxygen. a-Silica chemical structures are more randomly linked when compared to c-silica. All forms of silica are odorless solids composed of silicon and oxygen atoms. Silica particles become suspended in air and form non-explosive dusts. Silica may combine with other metallic elements and oxides to form silicates.Silica, amorphous (7631-86-9) is not classifiable as to carcinogenicity to humans. [IARC] Documentation and TLV withdrawn in 2006 because of insufficient data[ACGIH] The main problem in assessing the risk of exposure to diatomaceous earth is its varying degree of contamination with crystalline silica. While the natural version usually contains about 1%, up to 60% may be present in flux-calcined amorphous silica. [Rom, p. 527] |
| FDA 要件 | The food additive silicon dioxide may be safely used in food in accordance with /specified/ conditions.Silicon dioxide may be safely used as a component of articles intended for use in packaging, transporting, or holding food in accordance with prescribed conditions.The food additive silicon dioxide may be safely used in animal feed in accordance with /specified/ conditions. |
| 反応性グループ | Siloxanes |
| Special Reports | USEPA/Office of Pesticide ProgramsReregistration Eligibility Decision Document - Silicon Dioxide and Silica Gel. September 1991. The RED summarizes the risk assessment conclusions and outlines any risk reduction measures necessary for the pesticide to continue to be registered in the U.S.[Available from, as of December 2, 2003: http://www.epa.gov/pesticides/reregistration/status.htm] |
| EPA Safer Chemical | Chemical: Silica |
| FIFRA 要件 | Tolerance exemptions for minimal risk active and inert ingredients. Unless specifically excluded, residues resulting from the use of the following substances as either an inert or an active ingredient in a pesticide chemical formulation, including antimicrobial pesticide chemicals, are exempted from the requirement of a tolerance under FFDCA section 408, if such use is in accordance with good agricultural or manufacturing practices. Silica, amorphous, fumed (crystalline-free)silica, amorphous, precipitated and gelsilica gelsilica gel, precipitated, crystalline-free, silica, hydrateand silica, vitreous are included on this list.Residues of silicon dioxide, fumed, amorphous, are exempted from the requirement of a tolerance when used as a flow control, anticaking, and carrier agent in accordance with good agricultural practices as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops or to raw agricultural commodities after harvest.Silicon dioxide, fumed, amorphous exempted from the requirement of a tolerance when used as a flow control, anticaking, and carrier agent in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops only.As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996. Pesticides for which EPA had not issued Registration Standards prior to the effective date of FIFRA, as amended in 1988, were divided into three lists based upon their potential for human exposure and other factors, with List B containing pesticides of greater concern and List D pesticides of less concern. Silicon dioxide is found on List D. Case No: 4081Pesticide type: Insecticide,fungicide, antimicribialCase Status: RED Approved 09/91OPP has made a decision that some/all uses of the pesticide are eligible for reregistration, as reflected in a Reregistration Eligibility Decision (RED) document .Active ingredient (AI): silicon dioxideAI Status: OPP has completed a Reregistration Eligibility Decision (RED) document for the case/AI..The U. S. Environmental Protection Agency (EPA) conducted a review of the scientific data base and other relevant information supporting the reregistration of silicon dioxide and silica gel and has determined that the data base is sufficient to conduct a reasonable risk assessment. In addition, the Agency has conducted a tolerance reassessment for silicon dioxide and silica gel and its conclusions are discussed in Section IIC. The data available to the EPA support the conclusion that the currently registered uses of silicon dioxide and silica gel will not result in unreasonable public health risks or effects to the environment. No further generic data are required. Accordingly, the EPA has determined that all products containing silicon dioxide and silica gel as the active ingredients are eligible for reregistration and will be reregistered when appropriate labeling and/or product specific data are submitted and/or cited. Before reregistering each product, the EPA is requiring product specific data to be submitted within eight months of the issuance of this document. After reviewing these data and the revised labels, the EPA will determine whether to reregister a product based on whether or not the conditions of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Section 3(c)(5) have been met. End use products containing silicon dioxide and silica gel in combination with other active ingredients will not be reregistered until those other active ingredients are determined to be eligible for reregistration. |
| OSHA Standards | The PEL for amorphous silica is expressed by a formula that reduces the amount of dust to which a worker can be exposed as the percentage of amorphous silica in the dust rises. The term SiO2 refers to the percentage of amorphous silica in the sample. When the amorphous silica content is at or below 5.33% the total dust (Particulates Not Otherwise Regulated) PEL of 15 mg/m3 should be used. |
| Reactivity Profile | SILICA, AMORPHOUS is a non-combustible solid. Generally unreactive chemically. Incompatible with fluorine, oxygen difluoride, chlorine trifluoride. Soluble in molten alkalis and reacts with most metallic oxides at high temperature. |
| 消火 | In case of fire in the surroundings, use appropriate extinguishing media. |
| 応急処置措置 | Fresh air, rest.Rinse and then wash skin with water and soap.Rinse with plenty of water (remove contact lenses if easily possible).Rinse mouth. |
| 応急処置 | Excerpt from NIOSH Pocket Guide for Silica, amorphous:(General first aid procedures) |
| 安全保管 | Separated from strong oxidants. |
| 暴露管理・個人防護 | 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].0.3 [mg/m3], respir. fraction (diatomaceous earth calcined, silica fume, and fused)[German Research Foundation (DFG)] |
| 保管条件 | Avoid dusty atmosphere. /Cab-O-Sil*/PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practical to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/ |
| 清掃方法 | PRECAUTIONS FOR "CARCINOGENS": A high-efficiency particulate arrestor (HEPA) or charcoal filters can be used to minimize amt of carcinogen in exhausted air ventilated safety cabinets, lab hoods, glove boxes or animal rooms ... Filter housing that is designed so that used filters can be transferred into plastic bag without contaminating maintenance staff is avail commercially. Filters should be placed in plastic bags immediately after removal ... The plastic bag should be sealed immediately ... The sealed bag should be labelled properly ... Waste liquids ... should be placed or collected in proper containers for disposal. The lid should be secured & the bottles properly labelled. Once filled, bottles should be placed in plastic bag, so that outer surface ... is not contaminated ... The plastic bag should also be sealed & labelled. ... Broken glassware ... should be decontaminated by solvent extraction, by chemical destruction, or in specially designed incinerators. /Chemical Carcinogens/ |
| 処分方法 | SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure 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 qualitypotential migration in soil or watereffects on animal, aquatic, and plant lifeand conformance with environmental and public health regulations.PRECAUTIONS FOR "CARCINOGENS": There is no universal method of disposal that has been proved satisfactory for all carcinogenic compounds & specific methods of chem destruction ... published have not been tested on all kinds of carcinogen-containing waste. ... summary of avail methods & recommendations ... /given/ must be treated as guide only. /Chemical Carcinogens/PRECAUTIONS FOR "CARCINOGENS": ... Incineration may be only feasible method for disposal of contaminated laboratory waste from biological expt. However, not all incinerators are suitable for this purpose. The most efficient type ... is probably the gas-fired type, in which a first-stage combustion with a less than stoichiometric air:fuel ratio is followed by a second stage with excess air. Some ... are designed to accept ... aqueous & organic-solvent solutions, otherwise it is necessary ... to absorb soln onto suitable combustible material, such as sawdust. Alternatively, chem destruction may be used, esp when small quantities ... are to be destroyed in laboratory. /Chemical Carcinogens/PRECAUTIONS FOR "CARCINOGENS": HEPA (high-efficiency particulate arrestor) filters ... can be disposed of by incineration. For spent charcoal filters, the adsorbed material can be stripped off at high temp & carcinogenic wastes generated by this treatment conducted to & burned in an incinerator. ... LIQUID WASTE: ... Disposal should be carried out by incineration at temp that ... ensure complete combustion. SOLID WASTE: Carcasses of lab animals, cage litter & misc solid wastes ... should be disposed of by incineration at temp high enough to ensure destruction of chem carcinogens or their metabolites. /Chemical Carcinogens/For more Disposal Methods (Complete) data for CRYSTALLINE SILICA (6 total), please visit the HSDB record page. |
| 漏出処分 | Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Wash away remainder with plenty of water. |
| Preventive Measures | Wetting processes to control dusts must be used wherever feasible. Dust-producing operations should be segregated.SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.PRECAUTIONS FOR "CARCINOGENS": Smoking, drinking, eating, storage of food or of food & beverage containers or utensils, & the application of cosmetics should be prohibited in any laboratory. All personnel should remove gloves, if worn, after completion of procedures in which carcinogens have been used. They should ... wash ... hands, preferably using dispensers of liq detergent, & rinse ... thoroughly. Consideration should be given to appropriate methods for cleaning the skin, depending on nature of the contaminant. No standard procedure can be recommended, but the use of organic solvents should be avoided. Safety pipettes should be used for all pipetting. /Chemical Carcinogens/PRECAUTIONS FOR "CARCINOGENS": In animal laboratory, personnel should remove their outdoor clothes & wear protective suits (preferably disposable, one-piece & close-fitting at ankles & wrists), gloves, hair covering & overshoes. ... Clothing should be changed daily but ... discarded immediately if obvious contamination occurs ... /also,/ workers should shower immediately. In chemical laboratory, gloves & gowns should always be worn ... however, gloves should not be assumed to provide full protection. Carefully fitted masks or respirators may be necessary when working with particulates or gases, & disposable plastic aprons might provide addnl protection. If gowns are of distinctive color, this is a reminder that they should not be worn outside of lab. /Chemical Carcinogens/PRECAUTIONS FOR "CARCINOGENS": ... Operations connected with synth & purification ... should be carried out under well-ventilated hood. Analytical procedures ... should be carried out with care & vapors evolved during ... procedures should be removed. ... Expert advice should be obtained before existing fume cupboards are used ... & when new fume cupboards are installed. It is desirable that there be means for decreasing the rate of air extraction, so that carcinogenic powders can be handled without ... powder being blown around the hood. Glove boxes should be kept under negative air pressure. Air changes should be adequate, so that concn of vapors of volatile carcinogens will not occur. /Chemical Carcinogens/PRECAUTIONS FOR "CARCINOGENS": Vertical laminar-flow biological safety cabinets may be used for containment of in vitro procedures ... provided that the exhaust air flow is sufficient to provide an inward air flow at the face opening of the cabinet, & contaminated air plenums that are under positive pressure are leak-tight. Horizontal laminar-flow hoods or safety cabinets, where filtered air is blown across the working area towards the operator, should never be used ... Each cabinet or fume cupboard to be used ... should be tested before work is begun (eg, with fume bomb) & label fixed to it, giving date of test & avg air-flow measured. This test should be repeated periodically & after any structural changes. /Chemical Carcinogens/ |
| Eye Prevention | Wear safety goggles or eye protection in combination with breathing protection. |
| Inhalation Risk | A harmful concentration of airborne particles can be reached quickly when dispersed. |
| 毒性学的情報 | CDC-ATSDR Toxicological Profile |
| 相互作用 | Another form of amorphous silica, precipitated amorphous silica, /may/ form layers around quartz particles, which may facilitate the toxic action of quartz.Ameliorating effects of /poly-2-vinylpyridine-N-oxide/ PVNO were observed for pulmonary damage from colloidal SiO213 lead chromate-based pigments were assayed for mutagenicity and toxicity using Salmonella typhimurium TA100 with and without S9, both in the presence and absence of the chelating agent, nitrilotriacetic acid (NTA). In general, the use of NTA to solubilize the compounds resulted in /enhanced/ mutagenicity and/or toxicity ... . Encapsulation of pigments with amorphous silica rendered these pigments non-mutagenic and non-toxic, indicating that the active moieties were biologically unavailable to the bacteria.Lazaroid (U-75412E) scavenges .OH radicals generated by crystalline silica-mediated reaction from H2O2 and inhibits lipid peroxidation in macrophages induced by these particles.Occupational studies have found that the major source of co-morbidity with silicosis is infection by Mycobacterium tuberculosis (TB). |
| 標的器官 | Cancer, Immunological (Immune System), Renal (Urinary System or Kidneys), Respiratory (From the Nose to the Lungs)Eyes, respiratory system |
| 生態毒性値 | LC50 Carp >10,000 mg/l/72 hr /Conditions of bioassay not specified/ |
| 食品調査値 | Amorphous silica (such as fumed silica) is incorporated in a variety of food productsas anti-caking agent at levels up to 2% by weight ... also as an anti-caking agent and as an excipient in pharmaceuticals. |
| 有害作用 | Fibrogenic - Inducing tissue injury and fibrosis (scarring). |
| 暴露経路 | Exposure mainly occurs via inhalation.inhalation, skin and/or eye contact |
| 毒性の概要 | The Panel concluded that synthetically-manufactured amorphous Silica ... safe in the present practices of use and concentration described in the safety assessment when formulated to be non-irritating.Safe for use in cosmetics, with qualificationsIDENTIFICATION: Quartz is a frequently occurring solid component of most natural mineral dusts. HUMAN EXPOSURE: Human exposures to quartz occur most often during occupational activities that involve the movement of earth, disturbance of silica containing products (masonry, concrete), or use or manufacture of silica containing products. Environmental exposure to ambient quartz dust can occur during natural, industrial and agricultural activities. Respirable quartz dust particles can be inhaled and deposited in the lung. There are many epidemiological studies of occupational cohorts exposed to respirable quartz dust. Silicosis, lung cancer and pulmonary tuberculosis are associated with occupational exposure to quartz dust. Statistically significant increases in deaths or cases of bronchitis, emphysema, chronic obstructive pulmonary disease, autoimmune related diseases (scleroderma, rheumatoid arthritis, systemic lupus erythematosus) and renal diseases have been reported. Silicosis is the critical effect for hazard identification and risk assessment. There are sufficient epidemiological data to allow the risk of silicosis to be quantitatively estimated, but not to permit accurate estimations of risks for other health effects. ANIMAL STUDIES: Quartz dust induces cellular inflammation in vivo. Short term experimental studies of rats have found that intratracheal instillation of quartz particles leads to the formation of discrete silicotic nodules in rats, mice and hamsters. Inhalation of aerosolized quartz particles impairs alveolar macrophage clearance functions and leads to progressive lesions and pneumonitis. Oxidative stress (formation of hydroxyl radicals, reactive oxygen species, or reactive nitrogen species) has been observed in rats after intratracheal instillation or inhalation of quartz. Many experimental in vitro studies have found the surface characteristics of the crystalline silica particle influence its fibrogenic activity and a number of features related to its cytotoxicity. Long term inhalation studies of rats and mice have shown that quartz particles produce cellular proliferation, nodule formation, suppressed immune functions and alveolar proteinosis. Experimental studies of rats reported the occurrence of adenocarcinomas and squamous cell carcinomas after the inhalation or intratracheal instillation of quartz. Pulmonary tumors were not observed in experiments with hamsters or mice. Quartz did not test positively in standard bacterial mutagenesis assays. In experimental studies of particles, results may vary depending on the test material, concentration administered and species tested. The experiments with quartz particles involved specimens from various sources, using various doses, particle sizes and species. Data on the reproductive and developmental effects of quartz in laboratory animals are not available. The adverse effects of quartz in aquatic organisms and terrestrial mammals have not been studied. |
| Signs and Symptoms | Cough.Redness.Redness. Pain.No acute symptoms expected.irritation eyes, pneumoconiosis |
| Ongoing Test Status | The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical. /Silica, crystalline - quartz/ [http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=14808-60-7] |
| Effluent Concentrations | Silica fume, generated unintentionally and emitted from electric arc furnaces may contaminate work environments in silicon, ferrosilicon and other silicon-containing alloy production.Fly ash from power stations and various manufacturing facilities (e.g., silicon, silicous carbide, silicon nitride, ferrosilicon industries) may contain significant amounts of amorphous and crystalline silicaAmorphous silica fibers were identified as smoke constituents in three of seven area samples located near burning sugar cane fields in HawaiiAmorphous silica fibers were observed in samples collected /near/rice farming operations in California |
| Medical Surveillance | Along with lengthy occupational silica exposure and respiratory symptoms, diagnosis of chronic silicosis is confirmed with a positive X ray. The radiology community has agreed on a grading convention developed by the International Labour Organization (ILO) for assessing the severity of silicosis lesions (International Labour Organization, 1980). The X-ray opacities can range from mild (up to 1.5 mm) to moderate (1.5 to 3.0 mm) to severe (3 to 10 mm). These opacities are different from the diffuse lung changes that occur with age and cigarette smoking, but over time differentiation may be difficult. Chronic silicosis in its simplest form can be detected by X ray in the absence of any physical symptoms or clinical abnormalities.PRECAUTIONS FOR "CARCINOGENS": Whenever medical surveillance is indicated, in particular when exposure to a carcinogen has occurred, ad hoc decisions should be taken concerning ... /cytogenetic and/or other/ tests that might become useful or mandatory. /Chemical Carcinogens/ |
| F | 3 |
| 職業暴露区分（OEB） | B |
| 職業暴露限界（OEL） | TWA: 6.0 mg/m3 |
| 水環境危害等級（WGK） | 2 |
| TSCA 収載状態 | Yes |
| RTECS 番号 | VV7315000 |
| 輸送番号（UN） | 1993 |
| 危険文句（R） | 20-37-42/43-49-36/37-48/20-51/53-68-50/53-41-22-60 |
| 危険表示 | Xi,T,N,Xn |
| hazard_note | Harmful/Irritant |
| 安全措置（S） | 22-24/25-45-36/37-53-26-36-61-60-39 |
用途
解説
組成式SiO2･nH2Oで表されるゲル状の固体．可溶性ケイ酸水溶液を鉱酸で分解し，ゾルを経由してゲル化させ，水洗してつくられる．四面体型SiO2が重合し，重合の切れ目にはOHが結合し，さらにそれが水和した構造をもっている．水分子の数は条件によって変わる。天然に存在するケイ酸の多くはシリカゲルとして産する。合成品は、水ガラス（ケイ酸ナトリウム）水溶液と、硫酸または塩酸との複分解によって得られるシリカゾルをゲル化させる。普通、無色の粒状物として市販され、比重は2.2～2.3。酸には強いが濃アルカリ溶液に徐々に溶ける。水蒸気、アンモニアガスなど多くの物質に対して吸着力が強い。森北出版「化学辞典（第2版）
用途
一般脱湿乾燥用、炭酸ガスの吸着除去剤、天然ゴム?合成ゴムの明色補強配合剤、食品添加物 (化学工業日報社)
天然物の起源
Silica gels are dispersions of colloidal silica obtained by a sol–gel process. The process consists in precipitating colloidal silica from an aqueous solution of sodium silicate by adding hydrochloric or sulfuric acid. The colloidal precipitate or gel consists mainly of hydrated silica (SiO2 .nH2 O). After filtration the precipitated silica is washed in order to remove residual salts and stabilized by adding ammonia or sodium hydroxide. The stabilized gel is then dried and later calcined to obtain an activated material, usually in the form of small beads.
使用
Silica gel was used on glass plates for preparative TLC and on aluminium sheets for analytical TLC. Silica gel was used in vacuum chromatography and TLC. Silica gel was used in column chromatography.
一般的な説明
Silica gel is a rigid 3D network of colloidal silica. It is exclusively used as a support material for the active titanium(III) centers in Ziegler-Natta catalysts. Silica gel allows a controlled fragmentation lresulting in the formation of uniform polymer particles with narrow particle size distribution and high bulk density. Silica gel is classified as below:a. Aquagel - pores are filled with waterb. Xerogel - by the process of evaporation, aqueous phase in the pores are removedc. Aerogel - solvent removed by supercritical extraction
製法・合成法
純化方法
Before use as a drying agent, silica gel is heated in an oven, then cooled in a desiccator. Conditions in the literature range from heating at 110o for 15hours to 250o for 2-3hours. Silica gel has been purified by washing with hot acid (in one case successively with aqua regia, conc HNO3, then conc HCl; in another case it was digested overnight with hot conc H2SO4), followed by exhaustive washing with distilled water (one week in a Soxhlet apparatus has also been used), and prolonged oven drying. Alternatively, silica gel has been extracted with acetone until all soluble material was removed, then dried in a current of air, washed with distilled water and oven dried. Silica gel has also been washed successively with water, M HCl, water, and acetone, then activated at 110o for 15hours. Silicon monoxide [10097 -28 -6] M 44.1, m > 1700o, d 4 2.18. Purify the monoxide by sublimation in a porcelain tube in a furnace at 1250o (4hours) in a high vacuum (10-4mm) in a stream of N2. It is obtained as brownish black scales. [Schenk in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 696 1963.]