Isocyanate Puns

Hey all. So I redid my headlights of my car 6 months ago, and did the taillights today. I didnt realise it but the paint had isocyanates in it!

Its a 1 part clear. I read the 2Ks have isocyanates but that the one parts were free of them. Looked on the website today and they reported that spraying it does (but that rolling or painting it doesnt).

Both times spraying were outdoors with no mask (first time just had a hospital style mask for overspray. 4 coats on the headlights and 2 coats on the taillights, so just half a rattle can. I read up on isocyanates and holy crap I knew they weren't good but people are saying they can do permanent damage after a single overexposure. I sort of plan on never using autobody or industrial paints again.

Should I be concerned with even this level of exposure once?

Hey hi I am smooth bren I attempted to do the following problem and got the following answers. Did I get it right? Many thank

2C2H3NO + H2O → C3H8N2O + CO2

mC₃H₈N₂O = 32 433 129 g or 32,443 kg

mCO₂ = 16 200 000 g or 16,200 kg

Can anyone with experience with isocyanates tell me what precipitates would form from MDI, due to aging, freezing, and water exposure? I use MDI as a reagent for creation of another chemical used as an additive and there is a lot of residual MDI in it. We are seeing “solids” in the final formulation (it seems more like a gel due to oligomerization). I suspect it’s due to water from the packaging it’s stored in but I was wondering what other precipitates may form and if there is any way to prevent their formation or redissolve them after their formation. Any help would be appreciated.

Hi guys,

I have to start a reaction soon using 3-(triethoxysilyl)propyl isocyanate and I am a bit worried/scared after reading the MSDS. Any advice on how to work as safely as possible?

Thank you!

Turned out you need a certificate in Denmark if you work frequently with epoxy, even with gram quantities like in my case. Anybody aware of an english course around Copenhagen? So far I only found courses in Jylland

Unprecedented cycloaddition reactions of two isomeric (hydrido)diborane(4) anions with a homologous heterocumulene series proceed via B–B or B–H bond activation. Our diborane starting materials exhibit sterically exposed BHB cores, allowing us to contribute experimental evidence to the body of theoretical work on this class of [B2H5]− anion analogs.

Abstract

The intriguing (μ‐hydrido)diboranes(4) with their prominent pristine representative [B2H5]− have mainly been studied theoretically. We now describe the behavior of the planarized tetraaryl (μ‐hydrido)diborane(4) anion [1H]− in cycloaddition reactions with the homologous series of heterocumulenes CO2, iPrNCO, and iPrNCNiPr. We show that a C=O bond of CO2 selectively activates the B−B bond of [1H]−, while the μ‐H ligand is left untouched ([2H]−). The carbodiimide iPrNCNiPr, in contrast, neglects the B−B bond and rather adds the B‐bonded H− ion to its central C atom to generate a formamidinate bridge across the B2 pair ([3]−). As a hybrid, the isocyanate iPrNCO combines the reactivity patterns of both its congeners and gives two products: one of them ([4H]−) is related to [2H]−, the other ([5]−) is an analog of [3]−. We finally propose a mechanistic scenario that rationalizes the individual reaction outcomes and combines them to a coherent picture of B–B vs. B–H bond activation.

https://ift.tt/3lyRbwp

The direct copolymerization of epoxides with p‐tosyl isocyanate was achieved in the presence of trialkylborane and polyurethanes could be obtained without the formation of cyclic isocyanurate, in high linear/cyclic and urethane/imidocarbonate selectivity. The reported method provides access to the modification of properties of other polymers, especially aliphatic polycarbonates generated under the same conditions.

Abstract

The direct copolymerization of p‐tosyl isocyanate (TSI) with epoxides, initiated by onium salts in the presence of trialkylborane, to produce polyurethanes is reported. The rate of copolymerization and the (regio)selectivity were investigated in relation to the trialkylborane and the initiator used. Under optimized conditions such copolymerizations have been successfully performed for a wide range of epoxides, including ethylene oxide, propylene oxide, 1‐octene oxide, cyclohexene oxide, and allyl glycidyl ether. These copolymerizations afford a new category of polyurethanes, clear of side products such as cyclic oxazolidinone, isocyanurate, and poly(isocyanate) linkages. The experimental conditions used in this work are compatible with those for the organocatalytic (co)polymerization of other oxygenated monomers and CO2, holding the potential for their terpolymerization with p‐tosyl isocyanate and the development of new materials with unprecedented properties.

https://ift.tt/35AGaV9

Posted this on another sub but heard you guys are the experts so... I’m looking for some advice with regards to isocyanates. Is there a difference between polyisocyanates and isocyanates from a hazard point of view? I’m painting a bike at home and was going to put a 2K clear coat over the top of it so bought a couple of aerosols from Holts. Spec list says they contain polyisocyanates. Upon doing some research about what type of PPE I need, I discovered what an absolute horror show isocyanates are!! Where I live, using 2K or isocyanates at home isn’t illegal but I really don’t want to mess around with these chemicals or jeopardise my health (or my kids health or my neighbours’ dogs’ health). I will not be using this spray without an air fed system and I can’t afford one so I’ll have to find another option but if polyisocayantes are somehow less hazardous and I can use a 3M mask or something I’ll do that. This spray is available on Amazon and just says ‘wear a mask’, nothing about the dangers of isos so I’m very glad I did research first.

Anyone have any advice? Thanks

The zinc‐catalyzed selective reduction of isocyanates via hydroboration is reported for the first time. Amide bond formation by the chemoselective reduction of isocyanates and hydrodeoxygenation of isocyanates to secondary methyl amine have been described.

Abstract

Herein, a remarkable conjugated bis‐guanidinate (CBG) supported zinc hydride, [{LZnH}2; L={(ArHN)(ArN)−C=N−C=(NAr)(NHAr); Ar=2,6‐Et2‐C6H3}] (I) catalyzed partial reduction of heteroallenes via hydroboration is reported. A large number of aryl and alkyl isocyanates, including electron‐donating and withdrawing groups, undergo reduction to obtain selectively N‐boryl formamide, bis(boryl) hemiaminal and N‐boryl methyl amine products. The compound I effectively catalyzes the chemoselective reduction of various isocyanates, in which the construction of the amide bond occurs. Isocyanates undergo a deoxygenation hydroboration reaction, in which the C=O bond cleaves, leading to N‐boryl methyl amines. Several functionalities such as nitro, cyano, halide, and alkene groups are well‐tolerated. Furthermore, a series of kinetic, control experiments and structurally characterized intermediates suggest that the zinc hydride species are responsible for all reduction steps and breaking the C=O bond.

https://ift.tt/33MQ84d

Hello Electricians

I'm not an electrician, I'm a scientist. I needed some electrical work done at my house: basically ensuring that it meets all the new regulations, as we've sold it.

I let the guys get on with it, but when I went into the garage - they were rewiring lights and checking the hot water cylinder in there - I saw two used ±3ml vials of Isocyanate lying in there with their stuff.

They were at lunch at the time and afterwards I forgot to ask them what they would use that for while doing those jobs. I could call their office, I suppose, but it seems like a weirdly specific question to ask.

Google hasn't assisted, so I thought I'd come to the experts. Any ideas, please? I'm in South Africa if that makes any difference.

Thanks in advance.

https://preview.redd.it/6cl4qwjrofj61.png?width=1200&format=png&auto=webp&s=444b9ae3edc1696571d0d519ded4022c1ac6557e

A Swiss health organization (Blue Cross) had IQOS polymer filters tested when heated to 100°C and found that it emits isocyanate.

Media

• English: swissinfo
• German: Nau
• German: Tagesanzeiger
• German: 20 minutes
• German: bluewin
• German: Blick
• French: RTN

Isocyanate

This chemical is extremely toxic in even very low concentrations and will cause severe health damage in prolonged exposure. 3 months will see you severely sick, a year will see you dead.

It is the same chemical that's responsible for the Bhopal disaster where 8000 died within weeks and the impact to date is about 16'000 dead and 558'000 injured. Among the ongoing effects are fatty degeneration of the liver, stillbirths, fetus deformations and many others.

IQOS

These "heat not burn" electronic cigarettes consist of a heater "blade" that's shoved into a stick of PG-soaked tobacco and then the whole thing is heated to 350°C. The heating element is approximately 2cm long, the tobacco stick about 5cm long and then comes the polymer filter (allegedly made from PLA).

Phillip Morris denies that isocyanate is emitted in use, but admits that the filter contains isocyanate.

The Blue Cross contests that the filters partially melt during use, bringing them to temperatures sufficient to release isocyanate, but admits they didn't test isocyanate emission during actual use.

Previous research (reported by the guardian) has shown that

The direct copolymerization of epoxides with p‐tosyl isocyanate was achieved in the presence of trialkylborane and polyurethanes could be obtained without the formation of cyclic isocyanurate, in high linear/cyclic and urethane/imidocarbonate selectivity. The reported method provides access to the modification of properties of other polymers, especially aliphatic polycarbonates generated under the same conditions.

Abstract

The direct copolymerization of p‐tosyl isocyanate (TSI) with epoxides, initiated by onium salts in the presence of trialkylborane, to produce polyurethanes is reported. The rate of copolymerization and the (regio)selectivity were investigated in relation to the trialkylborane and the initiator used. Under optimized conditions such copolymerizations have been successfully performed for a wide range of epoxides, including ethylene oxide, propylene oxide, 1‐octene oxide, cyclohexene oxide, and allyl glycidyl ether. These copolymerizations afford a new category of polyurethanes, clear of side products such as cyclic oxazolidinone, isocyanurate, and poly(isocyanate) linkages. The experimental conditions used in this work are compatible with those for the organocatalytic (co)polymerization of other oxygenated monomers and CO2, holding the potential for their terpolymerization with p‐tosyl isocyanate and the development of new materials with unprecedented properties.

https://ift.tt/35AGaV9