Sulfuric acid exposure

Anonymous "Evaluation of Sulfur Acid Exposures from LDV (Light Duty Vehicles) Emissions", EPA, April 3, 1975. 

ASTM Standard C 1161-02C bend bars were scribed, weighed and randomly positioned within three small sample cups for sulfuric acid exposure. The simulated conditions were 60% H2SO4, 30% H2O and 10% air at 900°C. These sample cups were then loaded into the quartz... 

Figure 2. High temperature, high pressure, liquid sulfuric acid exposure apparatus.

Automotive workers (sulfuric acid exposure from batteries)... 

Sodium silicate mortars are available as either two component systems, which consist of the liquid sodium solution and the filler powder containing settling agents and selected aggregates, or they may be a one part system in powder form to be mixed with water when used. There are some differences in the chemical resistance between the two types. The differences in the chemical resistance of the two types of mortars are shown in Table 7.7. Sodium silicate mortars are useful in the pH range of 0-6, except where sulfuric acid exposures exist in the vapor phase, wet-dry exposures, or in concentrations above 93%. 

In studying the effects of polyethylene glycol (PEG) for decontamination of skin exposures to phenol and related compounds in rats, Brown et al. [209] also compared PEG and water decontamination for 45 % sodium hydroxide and concentrated sulfuric acid exposures [209], While water decontamination was more efficacious than PEG, chemical skin injuries of various severities developed in all the animals exposed to sulfuric acid and in 12 of 90 animals exposed to 45 % sodium hydroxide, despite water rinsing [209],... 

DIPHOTERINE solution, sodium bicarbonate, and tap water after 95 % sulfuric acid exposure... 

The effects of solvent exposure on the viscoelastic properties of several vinyl ester resins (phenohc-novolac epoxy, propoxylated bisphenol-A fu-marate, urethane and bisphenol-A epoxy based) and various unsaturated polyester resins (terephthalic or isophthaUc acid with a standard glycol based) containing 10wt% glass fiber were studied [130]. The results of dynamic mechanical analysis showed that the influence of exposure time to the solvent as well as the influence of temperature depended on the styrene content and chemical composition of the studied resins, while the amount of cobalt octoate used for the synthesis as the accelerator had no influence on the viscoelastic properties of the prepared materials after solvent exposure. It was also found that not fully cured urethane vinyl ester and the terephthahc acid-based unsaturated polyester resins showed excellent resistance to sulfuric acid exposure. However, interactions between the tested resins and petroleum could possibly occur through intermolecular bonding between the non-polar chains of the cured resins and the solvent. 

The radioactive isotopes available for use as precursors for radioactive tracer manufacturing include barium [ C]-carbonate [1882-53-7], tritium gas, p2p] phosphoric acid or pP]-phosphoric acid [15364-02-0], p S]-sulfuric acid [13770-01 -9], and sodium [ I]-iodide [24359-64-6]. It is from these chemical forms that the corresponding radioactive tracer chemicals are synthesized. [ C]-Carbon dioxide, [ C]-benzene, and [ C]-methyl iodide require vacuum-line handling in weU-ventilated fume hoods. Tritium gas, pH]-methyl iodide, sodium borotritide, and [ I]-iodine, which are the most difficult forms of these isotopes to contain, must be handled in specialized closed systems. Sodium p S]-sulfate and sodium [ I]-iodide must be handled similarly in closed systems to avoid the Uberation of volatile p S]-sulfur oxides and [ I]-iodine. Adequate shielding must be provided when handling P P]-phosphoric acid to minimize exposure to external radiation. 

Pan and cascade burners are generally more limited ia flexibiHty and are useful only where low sulfur dioxide concentrations are desired. Gases from sulfur burners also contain small amounts of sulfur trioxide, hence the moisture content of the air used can be important ia achieving a corrosion-free operation. Continuous operation at temperatures above the condensation poiat of the product gases is advisable where exposure to steel (qv) surfaces is iavolved. Pressure atomiziag-spray burners, which are particularly suitable when high capacities are needed, are offered by the designers of sulfuric acid plants. 

Health, Safety, and Environmental Factors. Sulfur dioxide has only a moderate acute toxicity (183). The lowest pubHshed human lethal concentration is 1000 ppm for 10 months. The lowest pubHshed human toxic concentration by inhalation is 3 ppm for 5 days or 12 ppm for 1 hour. The lowest pubHshed human lethal concentration is 3000 ppm for 5 months. In solution (as sulfurous acid), the lowest pubHshed toxic dose is 500 flg/kg causing gastrointestinal disturbances. Considerable data is available by other modes of exposure and to other species NIOSH standards are a time-weighted average of 2 ppm and a short-term exposure limit of 5 ppm (183). 

S. M. Horvath and co-workers. Effects of Sulfuric Acid Mist Exposure on Pulmonary Function, EPA-600/S1-81-044, issued as PB81-208977 by NTIS, Washington, D.C., June 1981. 

Safety. Chlorosulfuric acid is a strong acid and the principal ha2ard is severe chemical bums when the acid comes into contact with body tissue. The vapor is also ha2ardous and extremely irritating to the skin, eyes, nose, and respiratory tract. Exposure limits for chlorosulfuric acid have not been estabhshed by OSHA or ACGIH. However, chlorosulfuric acid fumes react readily with moisture in the air to form hydrochloric and sulfuric acid mists, which do have estabhshed limits. The OSHA 8-h TWA limits and ACGIH TLV—TWA limits are sulfuric acid = 1 mg/m hydrochloric acid = 5 ppm or 7 mg/m (ceiling limit). 

A similar procedure may be used for the preparation of /)-cyanobenzaldiacetate from -tolunitrile. Information submitted by Rorig and Nicholson, of G. D. Searle and Company, indicates that the critical step in this preparation is to maintain the reaction temperature below 10° throughout the process. Exposure of -cyanobenzaldiacetate to excess chromic, acetic, and sulfuric acids causes a reduction in yield. During the oxidation care should be taken to prevent chromium trioxide from adhering to the walls of the flask above the reaction mixture and then dropping in large amounts into the solution. 

Clean metallic aluminum is extremely reactive. Even exposure to air at ordinary temperatures is sufficient to promote immediate oxidation. This reactivity is self-inhibiting, however, which determines the general corrosion behavior of aluminum and its alloys due to the formation of a thin, inert, adherent oxide film. In view of the great importance of the surface film, it can be thickened by anodizing in a bath of 15% sulfuric acid (H2SO4) solution or by cladding with a thin layer of an aluminum alloy containing 1 % zinc. 

Although it is far more common to synthesize these substrates using the Feist-Benary reaction (Section 4.1), the Paal-Knorr reaction can also be used to prepare 2,3-disubstituted furans. In a recent example, Castagnoli converted 1,4-ketoaldehyde 40 into furan 41 in 97% yield upon exposure to hot sulfuric acid. ... 

Both 2,5-dialkyl-3-furoates and 2,5-dialkyl-3-phosphonofurans can be produced using the Paal-Knorr reaction. Methyl 2,5-diisopropyl-3-furoate (62) is available upon treatment of dione 61 with sulfuric acid. Phosphonodiones 63 can be efficiently converted into 2-substituted-3-diethylphosphono-5-methylfurans 64 by exposure to Amberlyst in refluxing toluene. ... 

The key step in this sequence, achieved by exposure of 46 lo a mixture of sulfuric acid and acetic anhydride, involves opening of the cyclopropane ring by migration of a sigma bond from the quaternary center to one terminus of the former cyclo-l>ropane. This complex rearrangement, rather reminiscent of the i enone-phenol reaction, serves to both build the proper carbon. keleton and to provide ring C in the proper oxidation state. 

Scheme 21 presents the successful sequence of reactions that solved the remaining two problems and led to the completion of the synthesis of cobyric acid. Exposure of 96 to concentrated sulfuric acid for one hour brings about a clean conversion of the nitrile grouping to the corresponding primary amide grouping. The stability of die corrin nucleus under these rather severe conditions is noteworthy. This new substance, intermediate 97, is identified as cobyrinic acid abcdeg hexamethylester f amide and it is produced along with a very similar substance which is epimeric to 97 at C-13. The action of sulfuric acid on 96 produces a diastereomeric... 

In this context, the esterification of 4-(l-pyrenyl)butyric acid with an alcohol to the corresponding ester was investigated [171]. Without the presence of sulfuric acid no reaction to the ester was foimd in the micro reactor. On activating the surface by a sulfuric acid/hydrogen peroxide mixture, however, a yield of 9% was achieved after 40 min at 50 °C. On making the surface hydrophobic by exposure to octadecyltrichlorosilane, no product formation was observed. Using silica gel in a laboratory-scale batch experiment resulted in conversion, but substantially lower than in the case of the micro reactor. The yield was no higher than 15% (40 min ... 

P 21] Solutions of 10 M 4-(l-pyrenyl)butyric acid in ethanol and 10 M sulfuric acid in ethanol were contacted in a micro-mixing tee/micro channel flow configuration at room temperature and at 50 °C [91]. Pressure-driven feed was used. The glass surface of the micro channels was either tuned hydrophobic (by exposure to octadecyltrichlorosilane) or hydrophilic (by wetting with a sulfuric acid/hydrogen peroxide mixture). 

The development of improved control instrumentation [e.g., of cathode location (placements), etc.] and many years of proven AP applications in the field have made AP the preferred method of controlling corrosion of uncoated steel equipment handling hot, concentrated sulfuric acid, stainless steel in even hotter exposures, and even steel in nitric acid. 

---