Hydrochloric acid exposure

Remijn B, Koster P, Houthuijs D, Boleij J, Willems H, Brunekreef B, Biersteker K, van Loveren C. Zinc chloride, zinc oxide, hydrochloric acid exposure and dental erosion in a zinc galvanizing plant in the Netherlands. Ann Occup Hyg 1982 25 299-307. 

Hydrogen chloride in air can also be a phytotoxicant (88). Tomatoes, sugar beets, and fmit trees of the Pmnus family are sensitive to HCl in air. Exposure of concentrated hydrochloric acid to the skin can cause chemical bums or dermatitis. Whereas the irritation is noticed readily, the acid can be water flushed from the exposed area. Copious use of miming water is the only recommended safety procedure for any external exposure. Ingestion is seldom a problem because hydrochloric acid is a normal constituent of the stomach juices. If significant quantities are accidentally swallowed, it can be neutrali2ed by antacids. 

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). 

After dilution with 200 ml. of benzene, the solution is transferred to a 2-1. separatory funnel containing 800 ml. of ice water and shaken thoroughly. The aqueous layer is separated, acidified to pH 3-4 with 2-3 ml. of concentrated hydrochloric acid, and extracted with three 100-ml. portions of benzene. All the organic layers are then combined and dried over anhydrous sodium sulfate. Filtration and concentration of the solution with a rotary evaporator, followed by exposure to high vacuum for 2-3 hours, affords 17.3-19.3 g. of the crude product (Note 3). Low-boiling impurities are removed by vacuum distillation (Note 4), the residual oil (14-15 g.) is transferred to a 50-ml. flask equipped with a short-path distillation apparatus, and vacuum distillation is continued. A forerun is taken until no rise in boiling point is observed, and then 7.2-8.6 g. (23-27%) of dimethyl nitrosuccinate is collected as a colorless oil, b.p. 85° (0.07 mm.), 1.4441 (Note 5). 

Reactions with aqueous solutions. Uniform dissolution or corrosion of metals in acid, alkaline or neutral solutions (e.g. dissolution of zinc in hydrochloric acid or in caustic soda solution general corrosion of zinc in water or during atmospheric exposure). Reactions with non-aqueous solution (e.g. dissolution of copper in a solution of ammonium acetate and bromine in alcohol). 

Exposure to hydrochloric acid vapor instead of application of 5<7b methanolic hydrochloric acid leads to approximately comparable results. 

Decontamination Complete cleansing of the skin with soap and water at the earliest opportunity. If washing is impossible, use the M258A1, M258, or M291 skin decontamination kit. Symptoms may appear as late as 36 h after contact exposure, even if the skin is washed within an hour. In fact, a delay in onset of several hours is typical. Use this time to prepare for the possibility of a widespread outbreak 6-24 h after the attack. Decontaminate bulk quantities of BZ with caustic alcohol solutions. If BZ or other belladonnoids are used as free bases, decontamination will require a solvent, such as 25% ethanol, 0.1 N hydrochloric acid, or 5% acetic acid. 

Concentrated hydrochloric acid is highly corrosive. Hydrochloric acid is primarily a concern in its aerosol form. Acid aerosols have been implicated in causing and exacerbating a variety of respiratory ailments. Dermal exposure and ingestion of highly concentrated hydrochloric acid can result in corrosivity. There is currently no evidence to suggest that this chemical is carcinogenic. 

The isoindolobenzazepine 380 obtained readily from prechilenine (139), 13-hydroxyoxyberberine (134), or oxybisberberine (130) (223), was recently isolated and named as chilenine (225). On reduction with zinc in hydrochloric acid-acetic acid 380 gave chilenamine (458) along with the hydroxylated product 459 (Scheme 94). Reduction of 380 followed by methylation and elimination of methanol gave pictonamine (460). On treatment with sodium hydroxide in aqueous methanol, 380 was converted to the isoindole 461, exposure of which to trifluoroacetic acid promoted cyclization and decarboxylation to afford the isoindoloisoquinoline neuvanine (462) (226). Its structure was revised (227) from the one originally proposed 463 (228). 

Clear liquid with a pungent odor similar to hydrochloric acid. Readily breaks down during storage often stabilized with water or calcium carbonate. Turns dark and forms resins on prolonged exposure to light. 

Having pyrazinylacetylenes in hand, one could convert the alkynyne functionality into the corresponding ketone via hydration [33], Thus, the coupling of iodide 36 and acetylene 37 produced pyrazinylalkyne 38. Subsequent exposure of 38 to aqueous sodium sulfide and aqueous hydrochloric acid in methanol led to ketone 39. Such a maneuver provides additional opportunities for further manipulation of the alkynes derived from the Sonogashira coupling reactions. 

Typically, acid soils are titrated with a sodium or calcium hydroxide [NaOH or Ca(OH)2] solution and basic soils with hydrochloric acid (HC1), and pH changes are most commonly followed using a pH meter. Carbonates in basic soils release C02 during treatment with HC1, thus making the titration more difficult. For this reason, carbonates are often determined by other methods. It is important to keep in mind that basic solutions react with carbon dioxide in air and form insoluble carbonates. This means that either the basic titrant is standardized each day before use or the solution is protected from exposure to carbon dioxide in air. Specific descriptions of titrant preparation, primary standards, and the use of indicators and pH meters in titrations can be found in Harris [1] and in Skoog et al. [2],... 

For aqueous HF of high concentrations (> 10%) or for elevated temperatures (above room temperature, RT), HF is in its most dangerous phase, the vapor phase. The liquid solution generates considerable amounts of HF vapor. HF has a stinging smell not unlike hydrochloric acid, and its smell is detectable at levels above 0.04 ppm. The permissible exposure limits in industrial countries vary from 0.5 to 2 mg nT3 (0.62-2.50 ppm). At 30 ppm, HF is immediately dangerous to life and health. An exposure to 50 ppm for 30 min can be lethal. It is self-evident that... 

Enteric bacterial pathogens must maneuver through a lengthy stretch of hazardous terrain before they reach their intended target or infection site within a host. Initially, they must tolerate salivary enzymes having various hydrolytic activities in the mouth, followed by exposure to shedded epithelial cells in the esophagus that may prevent local bacterial adherence (Pearson and Brownlee, 2005). In the stomach, bacteria must endure another severe environment created by the secretion of digestive enzymes and hydrochloric acid (up to 0.1 M concentration and a pH as low as 1.0). Once bacteria reach the intestines, they then encoimter mechanical. 

Various membrane materials are to be compared for corrosion resistance in hydrochloric acid. Membrane samples are ultrasonically cleaned with Freon for 5 minutes and dried at 200°C for 2 hours followed by similar steps of ultrasonic cleaning with demineralized water and drying. The conditioned membrane samples are then immersed in 35% HG solution, making sure that no air bubbles are trapped in pores. The acid exposure at the test temperature (e.g. 25°C) continues for a given period (e.g. one week). The tested samples are ultrasonically washed with demineralized water for 5 minutes and dried at 200°C for 2 hours. The weights of the cleaned membrane samples before and after the acid exposure are compared to assess the relative corrosion resistance of various membrane materials. 

No effeets were reported in rabbits when 100 mg of dichlorobenzidine (free base) was plaeed in the conjunctival sac of the eye (Gerarde and Gerarde 1974). It should be noted that the authors did not report the duration of exposure or the vehicle used. However, 0.1 mL of 3,3 -dichlorobenzidine dihydrochloride in a 20% com oil suspension produced eiythema, pus, and comeal opaeity, giving a 76% score in the Draize test within an hour when placed in the conjunctival sac of the eye of the rabbit (Gerarde and Gerarde 1974). This response is very likely associated with the release of hydrochloric acid following the salt s contact with the moist surface of the eye. 

The hydrochloric acid salt of 3,3 -dichlorobenzidine readily photolyses in water exposed to natural sunlight, but may not readily biodegrade in soil and aeelimated sludges. It has a strong tendency to partition to soils and sediments, a property which reduces the potential for human exposure (Boyd et al. 1984 Chung and Boyd 1987 Sikka et al. 1978). Once partitioned to soil, the compound apparently binds further with humie substances to form humie-like materials that presumably would be non-hazardous (Sikka et al. 1978). However, in a recent paper, Nyman et al. (1997) stated that dehalogenation of 3,3 -dichlorobenzidine to form benzidine (also a toxie substance) occurs in sediment/water mixtures under anaerobic conditions. 

Exposure of the skin to a high concentration of the gas or to a concentrated solution of the liquid (hydrochloric acid) will cause burns repeated or prolonged exposure to dilute solutions may cause dermatitis. Erosion of exposed teeth may also occur from repeated or prolonged exposure. Although ingestion is unlikely, hydrochloric acid causes severe burns of the mouth, esophagus, and stomach with consequent pain, nausea, and vomiting. ... 

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