MOCA

E. S. Baker, paper presented at aimual MOCA Meeting, Atlanta, Ga., Apr. 1994. 

More recently, storage systems based on MDI have become available which pose less of a health hazard than MDI/MOCA systems. Both polyethers and polyesters are used, with glycols being the usual chain extenders. 

Both TDI/MOCA and MDI/diol prepolymer systems are of importance for harder grades of printer s rollers and the wear-resisting applications such as pipes, pumps and impellers used in the mining and quarrying industries. 

Hlilse,/. hull, husk, pod, shell case cartridge case (MocA.) socket, collar, sleeve, etc. vial capsule spool, bobbin, hulsenartig, a. like a hull, socket, etc. (see HUlse) leguminous. 

At Moca, a lounge on Frederick Douglass Boulevard at 119th Street, the house drinks were perfect. I wish several didn t exist, including the French Kiss martini, which was its own best reason for never opening your mouth. 

Methylene bis (2-chloraniline) (MOCA) Methyl ethyl ketone (MEK), see 2-Butanone ST... 

Typical chain extenders that are used are MOCA (4,4-methylene bis orthochloro- aniline), butane diol or trimethylolpropane. 

Formation of the Initial Cyclitol. The first steps of FOR production are the same as in the biosynthesis of STR in short, the first step in FOR biosynthesis is postulated to be the formation of a myo-inositol monophosphate (D-myo-inositol-3-phosphate or L-myo-inositol-1-phosphate) via the cellular l-myo-inositol-1-phosphate synthase as in the STR pathway (Ca pathway see Section 2.2.1.2). As in the itr-Att-clusters, no gene for this enzyme has been found in the/or-cluster. As a second step in FOR biosynthesis the dephosphorylation of D-myo-inositol-3-phosphate via an inositolmonophosphate phosphatase has to follow. A putative gene product with this activity is that of the ForA protein (cf. Tables 2.17 and 2.18). The cyclitol is postulated to be first converted via two enzymes, a cluster-encoded myo-inositol 3-dehydrogenase (ForG member of the GFO/IDH/MocA oxidoreductase family) and the L-glutamine icy//o-3-inosose 3-aminotransferase (ketocyclitol aminotransferase I ForS), to icy//o-inosamine (3-deoxy-3-amino- cy/to-mositol). 

Synonyms Methylene bis(chloroaniline) DACPM MBOCA MOCA... 

Toxicology. 4,4 -Methylene bis(2-chloroani-line), or MOCA, is carcinogenic in experimental animals. 

MOCA causes low to moderate acute toxicity in animals, with marked species... 

In chronic studies rats fed 1000 ppm MOCA in a standard diet for 2 years developed lung tumors there were 2 5 adenomatoses and 48 adenocarcinomas in 88 rats. Accompanying liver changes included hepatocytomegaly, necrosis, bile duct proliferation, and fibrosis. In 88 control animals, there were two lung adenomatoses. MOCA in a low-protein diet caused lung tumors in rats of both sexes, liver tumors in males, and malignant mammary tumors in females. 

Repeated subcutaneous injection of MOCA in 34 rats (total dose 25g/kg for 620 days) resulted in nine liver cell carcinomas and seven lung carcinomas 13 of 50 control animals developed tumors, but no malignant tumors of the liver or the lungs were observed. ... 

MOCA was fed to male and female mice for 18 months at a dose of either 1 or 2 g/kg in female mice, but not in males, a statistically significant incidence of hepatoma was observed. In addition, a higher incidence of hemangiosarcomas and hemangiomas was observed in treated animals compared with controls. Urinary bladder tumors (primarily papillary transitional cell carcinomas) occurred in dogs given 100 mg of MOCA by capsule for up to 9.0 years. ... 

There was no evidence that MOCA was tumorigenic in a study of 31 active workers exposed from 6 months to 16 years. Quantitative analysis of the workers urine confirmed exposure to the chemical. In addition, the records were reviewed for 178 employees who at one time had worked with MOCA but who thereafter had had no further exposure for at least 10 years. The general health of exposed workers with respect to illness, absenteeism, and medical history was similar to that of the total plant population. Two deaths in this group due to malignancy had been diagnosed before any work with or exposure to MOCA. For the plant population in general, there were 115 cancer deaths/100,000 over a 15-year period... 

In another report three noninvasive papillary tumors of the bladder were identified in a screening of 540 MOCA workers two tumors occurred in men with completely normal urine screening who were under 30, had never smoked, and had no previous occupational exposure to known bladder carcinogens. ... 

Exposure to MOCA was believed to be the cause of urinary frequency and mild hematuria in two of six exposed workers however, a variety of other materials including toluene diisocyanate, polyester resins, polyether resins, and isocyanate-containing resins also were present. ... 

The lARC has determined that there is inadequate evidence for carcinogenicity to humans and sufficient evidence for carcinogenicity to animals. However, on the basis of animal experiments it was concluded that MOCA probably is carcinogenic to humans, and exposure by all routes should be monitored carefully ... 

MOCA is genotoxic in a wide variety of assays. It also forms adducts with DNA both in vivo and in vitro ... 

Stula EE, Barnes JR, Sherman H Urinary bladder tumors in dogs from 4,4 -methylene-bis (2-chloroaniline) (MOCA). J Environ Pathol Toxicol 1 31-50, 1977... 

Linch AL, O Conner GB, Barnes JR, et al Methylene-bis-orfl5o-chloroaniline (MOCA) Evaluation of hazards and exposure control. Am Ind Hyg Assoc J 32 802-819, 1971... 

Figure 6.55 Log-log plot of relative carcinogenic potencies for a group of chemicals against mutagenic potency as determined by the Ames test. The potency is the amount of chemical giving tumors in 50% of the animals or 100 mutant colonies (revertants) of Salmonella bacteria. Aflatoxin B, is the most potent and benzidine the least potent. Abbreviations Moca, 4,4,-methylene-b/s-(2-chloroaniline) mms, methylmethane sulfonate. Source From Ref. 16.

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